From 7847adacda5d35582c9f3e5720199ae001681781 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 17:04:12 -0800
Subject: [PATCH 01/24] Limit busy-wait loops in per-subinterpreter GIL test

Add explicit timeouts to the busy-wait coordination loops in the
Per-Subinterpreter GIL test in tests/test_with_catch/test_subinterpreter.cpp.
Previously those loops spun indefinitely waiting for shared atomics like
`started` and `sync` to change, which is fine when CPython's free-threading
and per-interpreter GIL behavior matches the test's expectations but becomes
pathologically bad when that behavior regresses: the `test_with_catch`
executable can then hang forever, causing our 3.14t CI jobs to time out
after 90 minutes.

This change keeps the structure and intent of the test but adds a
std::chrono::steady_clock deadline to each of the coordination loops,
using a conservative 10 second bound. Worker threads record a failure and
return if they hit the timeout, while the main thread fails the test via
Catch2 instead of hanging. That way, if future CPython free-threading
patches change the semantics again, the test will fail quickly and
produced a diagnosable error instead of wedging the CI job.
---
 tests/test_with_catch/test_subinterpreter.cpp | 62 ++++++++++++++++---
 1 file changed, 52 insertions(+), 10 deletions(-)

diff --git a/tests/test_with_catch/test_subinterpreter.cpp b/tests/test_with_catch/test_subinterpreter.cpp
index 3c7c35be19..928557d683 100644
--- a/tests/test_with_catch/test_subinterpreter.cpp
+++ b/tests/test_with_catch/test_subinterpreter.cpp
@@ -7,6 +7,7 @@
 PYBIND11_WARNING_DISABLE_MSVC(4996)
 
 #    include <catch.hpp>
+#    include <chrono>
 #    include <cstdlib>
 #    include <fstream>
 #    include <functional>
@@ -309,6 +310,9 @@ TEST_CASE("Per-Subinterpreter GIL") {
     sync = 0;
     failure = 0;
 
+    using clock = std::chrono::steady_clock;
+    constexpr auto wait_timeout = std::chrono::seconds(10);
+
 // REQUIRE throws on failure, so we can't use it within the thread
 #        define T_REQUIRE(status)                                                                 \
             do {                                                                                  \
@@ -318,8 +322,16 @@ TEST_CASE("Per-Subinterpreter GIL") {
             } while (0)
 
     auto &&thread_main = [&](int num) {
-        while (started == 0)
-            std::this_thread::sleep_for(std::chrono::microseconds(1));
+        {
+            auto deadline = clock::now() + wait_timeout;
+            while (started == 0) {
+                if (clock::now() > deadline) {
+                    T_REQUIRE(false);
+                    return;
+                }
+                std::this_thread::sleep_for(std::chrono::microseconds(1));
+            }
+        }
         ++started;
 
         py::gil_scoped_acquire gil;
@@ -370,15 +382,31 @@ TEST_CASE("Per-Subinterpreter GIL") {
 
             // wait for something to set sync to our thread number
             // we are holding our subinterpreter's GIL
-            while (sync != num)
-                std::this_thread::sleep_for(std::chrono::microseconds(1));
+            {
+                auto deadline = clock::now() + wait_timeout;
+                while (sync != num) {
+                    if (clock::now() > deadline) {
+                        T_REQUIRE(false);
+                        return;
+                    }
+                    std::this_thread::sleep_for(std::chrono::microseconds(1));
+                }
+            }
 
             // now change it so the next thread can move on
             ++sync;
 
             // but keep holding the GIL until after the next thread moves on as well
-            while (sync == num + 1)
-                std::this_thread::sleep_for(std::chrono::microseconds(1));
+            {
+                auto deadline = clock::now() + wait_timeout;
+                while (sync == num + 1) {
+                    if (clock::now() > deadline) {
+                        T_REQUIRE(false);
+                        return;
+                    }
+                    std::this_thread::sleep_for(std::chrono::microseconds(1));
+                }
+            }
 
             // one last check before quitting the thread, the internals should be different
             auto sub_int
@@ -395,8 +423,15 @@ TEST_CASE("Per-Subinterpreter GIL") {
     ++started;
 
     // ok now wait for the threads to start
-    while (started != 3)
-        std::this_thread::sleep_for(std::chrono::microseconds(1));
+    {
+        auto deadline = clock::now() + wait_timeout;
+        while (started != 3) {
+            if (clock::now() > deadline) {
+                FAIL("Timeout while waiting for worker threads to start");
+            }
+            std::this_thread::sleep_for(std::chrono::microseconds(1));
+        }
+    }
 
     // we still hold the main GIL, at this point both threads are waiting on the main GIL
     // IN THE CASE of free threading, the threads are waiting on sync (because there is no GIL)
@@ -414,8 +449,15 @@ TEST_CASE("Per-Subinterpreter GIL") {
         sync = 1;
 
         // wait for thread 2 to advance
-        while (sync != 3)
-            std::this_thread::sleep_for(std::chrono::microseconds(1));
+        {
+            auto deadline = clock::now() + wait_timeout;
+            while (sync != 3) {
+                if (clock::now() > deadline) {
+                    FAIL("Timeout while waiting for sync to reach 3");
+                }
+                std::this_thread::sleep_for(std::chrono::microseconds(1));
+            }
+        }
 
         // we know now that thread 1 has run and may be finishing
         // and thread 2 is waiting for permission to advance

From 32725f761b9ca88cd215c4fa4b60bfe8faab5b61 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 19:04:35 -0800
Subject: [PATCH 02/24] Revert "Limit busy-wait loops in per-subinterpreter GIL
 test"

This reverts commit 7847adacda5d35582c9f3e5720199ae001681781.
---
 tests/test_with_catch/test_subinterpreter.cpp | 62 +++----------------
 1 file changed, 10 insertions(+), 52 deletions(-)

diff --git a/tests/test_with_catch/test_subinterpreter.cpp b/tests/test_with_catch/test_subinterpreter.cpp
index 928557d683..3c7c35be19 100644
--- a/tests/test_with_catch/test_subinterpreter.cpp
+++ b/tests/test_with_catch/test_subinterpreter.cpp
@@ -7,7 +7,6 @@
 PYBIND11_WARNING_DISABLE_MSVC(4996)
 
 #    include <catch.hpp>
-#    include <chrono>
 #    include <cstdlib>
 #    include <fstream>
 #    include <functional>
@@ -310,9 +309,6 @@ TEST_CASE("Per-Subinterpreter GIL") {
     sync = 0;
     failure = 0;
 
-    using clock = std::chrono::steady_clock;
-    constexpr auto wait_timeout = std::chrono::seconds(10);
-
 // REQUIRE throws on failure, so we can't use it within the thread
 #        define T_REQUIRE(status)                                                                 \
             do {                                                                                  \
@@ -322,16 +318,8 @@ TEST_CASE("Per-Subinterpreter GIL") {
             } while (0)
 
     auto &&thread_main = [&](int num) {
-        {
-            auto deadline = clock::now() + wait_timeout;
-            while (started == 0) {
-                if (clock::now() > deadline) {
-                    T_REQUIRE(false);
-                    return;
-                }
-                std::this_thread::sleep_for(std::chrono::microseconds(1));
-            }
-        }
+        while (started == 0)
+            std::this_thread::sleep_for(std::chrono::microseconds(1));
         ++started;
 
         py::gil_scoped_acquire gil;
@@ -382,31 +370,15 @@ TEST_CASE("Per-Subinterpreter GIL") {
 
             // wait for something to set sync to our thread number
             // we are holding our subinterpreter's GIL
-            {
-                auto deadline = clock::now() + wait_timeout;
-                while (sync != num) {
-                    if (clock::now() > deadline) {
-                        T_REQUIRE(false);
-                        return;
-                    }
-                    std::this_thread::sleep_for(std::chrono::microseconds(1));
-                }
-            }
+            while (sync != num)
+                std::this_thread::sleep_for(std::chrono::microseconds(1));
 
             // now change it so the next thread can move on
             ++sync;
 
             // but keep holding the GIL until after the next thread moves on as well
-            {
-                auto deadline = clock::now() + wait_timeout;
-                while (sync == num + 1) {
-                    if (clock::now() > deadline) {
-                        T_REQUIRE(false);
-                        return;
-                    }
-                    std::this_thread::sleep_for(std::chrono::microseconds(1));
-                }
-            }
+            while (sync == num + 1)
+                std::this_thread::sleep_for(std::chrono::microseconds(1));
 
             // one last check before quitting the thread, the internals should be different
             auto sub_int
@@ -423,15 +395,8 @@ TEST_CASE("Per-Subinterpreter GIL") {
     ++started;
 
     // ok now wait for the threads to start
-    {
-        auto deadline = clock::now() + wait_timeout;
-        while (started != 3) {
-            if (clock::now() > deadline) {
-                FAIL("Timeout while waiting for worker threads to start");
-            }
-            std::this_thread::sleep_for(std::chrono::microseconds(1));
-        }
-    }
+    while (started != 3)
+        std::this_thread::sleep_for(std::chrono::microseconds(1));
 
     // we still hold the main GIL, at this point both threads are waiting on the main GIL
     // IN THE CASE of free threading, the threads are waiting on sync (because there is no GIL)
@@ -449,15 +414,8 @@ TEST_CASE("Per-Subinterpreter GIL") {
         sync = 1;
 
         // wait for thread 2 to advance
-        {
-            auto deadline = clock::now() + wait_timeout;
-            while (sync != 3) {
-                if (clock::now() > deadline) {
-                    FAIL("Timeout while waiting for sync to reach 3");
-                }
-                std::this_thread::sleep_for(std::chrono::microseconds(1));
-            }
-        }
+        while (sync != 3)
+            std::this_thread::sleep_for(std::chrono::microseconds(1));
 
         // we know now that thread 1 has run and may be finishing
         // and thread 2 is waiting for permission to advance

From 179a66f606ed921064370aec736bab84f459b68b Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 19:05:01 -0800
Subject: [PATCH 03/24] Add progress reporter for test_with_catch Catch runner

Introduce a custom Catch2 reporter for tests/test_with_catch that prints a
simple one-line status for each test case as it starts and ends, and wire the
cpptest CMake target to invoke test_with_catch with -r progress. This makes
it much easier to see where the embedded/interpreter test binary is spending
its time in CI logs, and in particular to pinpoint which test case is stuck
when the free-threading builds hang.

Compared to adding ad hoc timeouts around potentially infinite busy-wait
loops in individual tests, a progress reporter is a more general and robust
approach: it gives visibility into all tests (including future ones) without
changing their behavior, and turns otherwise opaque 90-minute timeouts into
locatable issues in the Catch output.
---
 tests/test_with_catch/catch.cpp | 45 +++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/tests/test_with_catch/catch.cpp b/tests/test_with_catch/catch.cpp
index 5bd8b3880e..aa5de2f3c5 100644
--- a/tests/test_with_catch/catch.cpp
+++ b/tests/test_with_catch/catch.cpp
@@ -13,10 +13,55 @@ PYBIND11_WARNING_DISABLE_MSVC(4996)
 #endif
 
 #define CATCH_CONFIG_RUNNER
+#define CATCH_CONFIG_DEFAULT_REPORTER "progress"
 #include <catch.hpp>
 
 namespace py = pybind11;
 
+// Simple progress reporter that prints a line per test case.
+namespace {
+
+class ProgressReporter : public Catch::CumulativeReporterBase<ProgressReporter> {
+public:
+    using CumulativeReporterBase::CumulativeReporterBase;
+
+    static std::string getDescription() { return "Simple progress reporter (one line per test)"; }
+
+    void testCaseStarting(Catch::TestCaseInfo const &testInfo) override {
+        stream << "[ RUN      ] " << testInfo.name << '\n';
+        stream.flush();
+        CumulativeReporterBase::testCaseStarting(testInfo);
+    }
+
+    void testCaseEnded(Catch::TestCaseStats const &testCaseStats) override {
+        auto const &info = testCaseStats.testInfo;
+        bool failed = (testCaseStats.totals.assertions.failed > 0);
+        stream << (failed ? "[  FAILED  ] " : "[       OK ] ") << info.name << '\n';
+        stream.flush();
+        CumulativeReporterBase::testCaseEnded(testCaseStats);
+    }
+
+    static std::set<Catch::Verbosity> getSupportedVerbosities() {
+        return {Catch::Verbosity::Normal};
+    }
+
+    void testRunEndedCumulative() override {}
+
+    void noMatchingTestCases(std::string const &spec) override {
+        stream << "[  NO TEST ] no matching test cases for spec: " << spec << '\n';
+        stream.flush();
+    }
+
+    void reportInvalidArguments(std::string const &arg) override {
+        stream << "[   ERROR  ] invalid Catch2 arguments: " << arg << '\n';
+        stream.flush();
+    }
+};
+
+} // namespace
+
+CATCH_REGISTER_REPORTER("progress", ProgressReporter)
+
 int main(int argc, char *argv[]) {
     // Setup for TEST_CASE in test_interpreter.cpp, tagging on a large random number:
     std::string updated_pythonpath("pybind11_test_with_catch_PYTHONPATH_2099743835476552");

From 60ae0e8f744904ba2499cf44a43fdf91049f6e4a Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 19:14:44 -0800
Subject: [PATCH 04/24] Temporarily limit CI to Python 3.14t free-threading
 jobs

---
 .github/workflows/ci.yml | 131 ++++++---------------------------------
 1 file changed, 18 insertions(+), 113 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d00ee6d27e..0653b2adcd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,27 +35,9 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - runs-on: ubuntu-22.04
-            python-version: '3.8'
-            cmake-args: -DPYBIND11_FINDPYTHON=OFF -DPYBIND11_NUMPY_1_ONLY=ON
-          - runs-on: ubuntu-latest
-            python-version: '3.13'
-            cmake-args: -DCMAKE_CXX_STANDARD=23 -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
           - runs-on: ubuntu-latest
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
-          - runs-on: ubuntu-latest
-            python-version: 'pypy3.11'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: ubuntu-latest
-            python-version: 'graalpy-24.2'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
-          - runs-on: macos-latest
-            python-version: '3.14'
-            cmake-args: -DCMAKE_CXX_STANDARD=14
-          - runs-on: windows-2022
-            python-version: '3.8'
-            cmake-args: -DPYBIND11_FINDPYTHON=OFF
 
 
     name: 🐍
@@ -71,90 +53,12 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - runs-on: ubuntu-latest
-            python-version: '3.8'
-            cmake-args: -DPYBIND11_FINDPYTHON=ON -DCMAKE_CXX_STANDARD=17
-          - runs-on: ubuntu-latest
-            python-version: '3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
-          - runs-on: ubuntu-latest
-            python-version: '3.11'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_STANDARD=17
-          - runs-on: ubuntu-latest
-            python-version: '3.12'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
-          - runs-on: ubuntu-latest
-            python-version: '3.13t'
-            cmake-args: -DCMAKE_CXX_STANDARD=20 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
-          - runs-on: ubuntu-latest
-            python-version: '3.14'
-            cmake-args: -DCMAKE_CXX_STANDARD=14 -DCMAKE_CXX_FLAGS="-DPYBIND11_HAS_SUBINTERPRETER_SUPPORT=0"
-          - runs-on: ubuntu-latest
-            python-version: 'pypy-3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=14
-          - runs-on: ubuntu-latest
-            python-version: 'graalpy-24.1'
-
-          # No SciPy for macOS ARM
-          - runs-on: macos-15-intel
-            python-version: '3.8'
-            cmake-args: -DCMAKE_CXX_STANDARD=14
-          - runs-on: macos-15-intel
-            python-version: '3.11'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
-          - runs-on: macos-latest
-            python-version: '3.12'
-            cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
-          - runs-on: macos-15-intel
-            python-version: '3.13t'
-            cmake-args: -DCMAKE_CXX_STANDARD=11
           - runs-on: macos-latest
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=20
-          - runs-on: macos-15-intel
-            python-version: 'pypy-3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: macos-latest
-            python-version: 'pypy-3.11'
-          - runs-on: macos-latest
-            python-version: 'graalpy-24.2'
-
-          - runs-on: windows-latest
-            python-version: '3.9'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
-          - runs-on: windows-2022
-            python-version: '3.8'
-            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DPYBIND11_NUMPY_1_ONLY=ON
-          - runs-on: windows-2022
-            python-version: '3.9'
-            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDLL -DCMAKE_CXX_STANDARD=14
-          # This needs a python built with MTd
-          # - runs-on: windows-2022
-          #   python-version: '3.11'
-          #   cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebug
-          - runs-on: windows-2022
-            python-version: '3.10'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_FLAGS="/GR /EHsc"
-          - runs-on: windows-2022
-            python-version: '3.13'
-            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebugDLL
-          - runs-on: windows-latest
-            python-version: '3.13t'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: windows-latest
-            python-version: '3.14'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: windows-latest
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=23
-          - runs-on: windows-latest
-            python-version: 'pypy-3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: windows-latest
-            python-version: 'pypy3.11'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
-          # The setup-python action currently doesn't have graalpy for windows
-          # See https://github.com/actions/setup-python/pull/880
 
     name: 🐍
     uses: ./.github/workflows/reusable-standard.yml
@@ -165,7 +69,7 @@ jobs:
 
   # This checks inplace builds with C++11
   inplace:
-    if: github.event.pull_request.draft == false
+    if: false
     strategy:
       fail-fast: false
       matrix:
@@ -240,7 +144,7 @@ jobs:
 
   manylinux:
     name: Manylinux on 🐍 3.13t • GIL
-    if: github.event.pull_request.draft == false
+    if: false
     runs-on: ubuntu-latest
     timeout-minutes: 40
     container: quay.io/pypa/musllinux_1_2_x86_64:latest
@@ -265,7 +169,7 @@ jobs:
         run: cmake --build --preset testsvenv -t pytest
 
   deadsnakes:
-    if: github.event.pull_request.draft == false
+    if: false
     strategy:
       fail-fast: false
       matrix:
@@ -346,7 +250,7 @@ jobs:
 
   # Testing on clang using the excellent silkeh clang docker images
   clang:
-    if: github.event.pull_request.draft == false
+    if: false
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -403,6 +307,7 @@ jobs:
 
   # Testing NVCC; forces sources to behave like .cu files
   cuda:
+    if: false
     runs-on: ubuntu-latest
     name: "🐍 3.10 • CUDA 12.2 • Ubuntu 22.04"
     container: nvidia/cuda:12.2.0-devel-ubuntu22.04
@@ -471,7 +376,7 @@ jobs:
 
   # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
-    if: github.event.pull_request.draft == false
+    if: false
     runs-on: ubuntu-22.04
     name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
@@ -526,7 +431,7 @@ jobs:
 
   # Testing on GCC using the GCC docker images (only recent images supported)
   gcc:
-    if: github.event.pull_request.draft == false
+    if: false
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -599,7 +504,7 @@ jobs:
 
   # Testing on ICC using the oneAPI apt repo
   icc:
-    if: github.event.pull_request.draft == false
+    if: false
     runs-on: ubuntu-22.04
     timeout-minutes: 90
 
@@ -705,7 +610,7 @@ jobs:
 
   # Testing on CentOS (manylinux uses a centos base).
   centos:
-    if: github.event.pull_request.draft == false
+    if: false
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -771,7 +676,7 @@ jobs:
 
   # This tests an "install" with the CMake tools
   install-classic:
-    if: github.event.pull_request.draft == false
+    if: false
     name: "🐍 3.9 • Debian • x86 •  Install"
     runs-on: ubuntu-latest
     container: i386/debian:bullseye
@@ -817,7 +722,7 @@ jobs:
   # This verifies that the documentation is not horribly broken, and does a
   # basic validation check on the SDist.
   doxygen:
-    if: github.event.pull_request.draft == false
+    if: false
     name: "Documentation build test"
     runs-on: ubuntu-latest
     timeout-minutes: 90
@@ -853,7 +758,7 @@ jobs:
         diff -rq $installed ./pybind11
 
   win32:
-    if: github.event.pull_request.draft == false
+    if: false
     strategy:
       fail-fast: false
       matrix:
@@ -908,7 +813,7 @@ jobs:
       run: cmake --build build -t pytest
 
   win32-debug:
-    if: github.event.pull_request.draft == false
+    if: false
     strategy:
       fail-fast: false
       matrix:
@@ -960,7 +865,7 @@ jobs:
 
 
   windows-2022:
-    if: github.event.pull_request.draft == false
+    if: false
     strategy:
       fail-fast: false
       matrix:
@@ -1024,7 +929,7 @@ jobs:
       run: cmake --build build_partial --target pytest
 
   mingw:
-    if: github.event.pull_request.draft == false
+    if: false
     name: "🐍 3 • windows-latest • ${{ matrix.sys }}"
     runs-on: windows-latest
     timeout-minutes: 90
@@ -1133,7 +1038,7 @@ jobs:
       run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cross_module_rtti
 
   windows_clang:
-    if: github.event.pull_request.draft == false
+    if: false
 
     strategy:
       matrix:
@@ -1208,7 +1113,7 @@ jobs:
 
   # Clang with MSVC/Windows SDK toolchain + python.org CPython (Windows ARM)
   windows_arm_clang_msvc:
-    if: github.event.pull_request.draft == false
+    if: false
 
     strategy:
       fail-fast: false
@@ -1267,7 +1172,7 @@ jobs:
 
   # Clang in MSYS2/MinGW-w64 CLANGARM64 toolchain + MSYS2 Python (Windows ARM)
   windows_arm_clang_msys2:
-    if: github.event.pull_request.draft == false
+    if: false
 
     strategy:
       fail-fast: false

From 0fe6a42a0406f32178429fa8b50de206b6db37d2 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 19:19:54 -0800
Subject: [PATCH 05/24] Temporarily remove non-CI GitHub workflow files

---
 .github/workflows/configure.yml  |  85 ----------------------
 .github/workflows/docs-link.yml  |  41 -----------
 .github/workflows/format.yml     |  54 --------------
 .github/workflows/labeler.yml    |  25 -------
 .github/workflows/nightlies.yml  |  59 ----------------
 .github/workflows/pip.yml        | 118 -------------------------------
 .github/workflows/tests-cibw.yml |  95 -------------------------
 .github/workflows/upstream.yml   | 116 ------------------------------
 8 files changed, 593 deletions(-)
 delete mode 100644 .github/workflows/configure.yml
 delete mode 100644 .github/workflows/docs-link.yml
 delete mode 100644 .github/workflows/format.yml
 delete mode 100644 .github/workflows/labeler.yml
 delete mode 100644 .github/workflows/nightlies.yml
 delete mode 100644 .github/workflows/pip.yml
 delete mode 100644 .github/workflows/tests-cibw.yml
 delete mode 100644 .github/workflows/upstream.yml

diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
deleted file mode 100644
index cd034c883f..0000000000
--- a/.github/workflows/configure.yml
+++ /dev/null
@@ -1,85 +0,0 @@
-name: Config
-
-on:
-  workflow_dispatch:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-      - reopened
-      - ready_for_review
-  push:
-    branches:
-      - master
-      - stable
-      - v*
-
-permissions:
-  contents: read
-
-jobs:
-  # This tests various versions of CMake in various combinations, to make sure
-  # the configure step passes.
-  cmake:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-        - runs-on: ubuntu-22.04
-          cmake: "3.15"
-
-        - runs-on: ubuntu-24.04
-          cmake: "3.26"
-
-        - runs-on: ubuntu-24.04
-          cmake: "3.29"
-
-        - runs-on: macos-15-intel
-          cmake: "3.15"
-
-        - runs-on: macos-14
-          cmake: "4.0"
-
-        - runs-on: windows-latest
-          cmake: "4.0"
-
-    name: 🐍 3.11 • CMake ${{ matrix.cmake }} • ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python 3.11
-      uses: actions/setup-python@v6
-      with:
-        python-version: 3.11
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-
-    - name: Prepare env
-      run: uv pip install --python=python --system -r tests/requirements.txt
-
-    # An action for adding a specific version of CMake:
-    #   https://github.com/jwlawson/actions-setup-cmake
-    - name: Setup CMake ${{ matrix.cmake }}
-      uses: jwlawson/actions-setup-cmake@v2.0
-      with:
-        cmake-version: ${{ matrix.cmake }}
-
-    # These steps use a directory with a space in it intentionally
-    - name: Configure
-      shell: bash
-      run: cmake -S. -B"build dir" -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-
-    # Only build and test if this was manually triggered in the GitHub UI
-    - name: Build
-      working-directory: build dir
-      if: github.event_name == 'workflow_dispatch'
-      run: cmake --build . --config Release
-
-    - name: Test
-      working-directory: build dir
-      if: github.event_name == 'workflow_dispatch'
-      run: cmake --build . --config Release --target check
diff --git a/.github/workflows/docs-link.yml b/.github/workflows/docs-link.yml
deleted file mode 100644
index ea25410cb9..0000000000
--- a/.github/workflows/docs-link.yml
+++ /dev/null
@@ -1,41 +0,0 @@
-name: Read the Docs PR preview
-
-on:
-  pull_request_target:
-    types:
-      - opened
-      - synchronize
-
-permissions:
-  contents: read
-  pull-requests: write
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-jobs:
-  documentation-links:
-    runs-on: ubuntu-latest
-    if: github.event.repository.fork == false
-    steps:
-      - uses: actions/checkout@v6
-
-      - name: Check for docs changes
-        id: docs_changes
-        run: |
-          # Fetch the PR head
-          git fetch origin pull/${{ github.event.pull_request.number }}/head:pr-head
-
-          # Show diff between base (current checkout) and PR head
-          if git diff --name-only HEAD pr-head | grep -q '^docs/'; then
-            echo "docs_changed=true" >> "$GITHUB_OUTPUT"
-          else
-            echo "docs_changed=false" >> "$GITHUB_OUTPUT"
-          fi
-
-      - uses: readthedocs/actions/preview@v1
-        if: steps.docs_changes.outputs.docs_changed == 'true'
-        with:
-          project-slug: "pybind11"
-          single-version: "true"
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
deleted file mode 100644
index 6bf77324a9..0000000000
--- a/.github/workflows/format.yml
+++ /dev/null
@@ -1,54 +0,0 @@
-# This is a format job. Pre-commit has a first-party GitHub action, so we use
-# that: https://github.com/pre-commit/action
-
-name: Format
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-    - master
-    - stable
-    - "v*"
-
-permissions:
-  contents: read
-
-env:
-  FORCE_COLOR: 3
-  # For cmake:
-  VERBOSE: 1
-
-jobs:
-  pre-commit:
-    name: Format
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v6
-    - uses: actions/setup-python@v6
-      with:
-        python-version: "3.x"
-    - name: Add matchers
-      run: echo "::add-matcher::$GITHUB_WORKSPACE/.github/matchers/pylint.json"
-    - uses: pre-commit/action@v3.0.1
-
-  clang-tidy:
-    # When making changes here, please also review the "Clang-Tidy" section
-    # in .github/CONTRIBUTING.md and update as needed.
-    name: Clang-Tidy
-    runs-on: ubuntu-latest
-    container: silkeh/clang:20
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Install requirements
-      run: apt-get update && apt-get install -y git python3-dev python3-pytest ninja-build
-
-    - name: Configure
-      run: cmake --preset tidy
-    - name: Build
-      run: cmake --build --preset tidy
-
-    - name: Embedded
-      run: cmake --build --preset tidy -t cpptest
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
deleted file mode 100644
index f5b618ba82..0000000000
--- a/.github/workflows/labeler.yml
+++ /dev/null
@@ -1,25 +0,0 @@
-name: Labeler
-on:
-  pull_request_target:
-    types: [closed]
-
-permissions: {}
-
-jobs:
-  label:
-    name: Labeler
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      pull-requests: write
-    steps:
-
-    - uses: actions/labeler@v6
-      if: >
-        github.event.pull_request.merged == true &&
-        !startsWith(github.event.pull_request.title, 'chore(deps):') &&
-        !startsWith(github.event.pull_request.title, 'ci(fix):') &&
-        !startsWith(github.event.pull_request.title, 'docs(changelog):')
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        configuration-path: .github/labeler_merged.yml
diff --git a/.github/workflows/nightlies.yml b/.github/workflows/nightlies.yml
deleted file mode 100644
index ad4a351521..0000000000
--- a/.github/workflows/nightlies.yml
+++ /dev/null
@@ -1,59 +0,0 @@
-name: Upload nightly wheels to Anaconda Cloud
-
-on:
-  # Run daily at 2:34 UTC to upload nightly wheels to Anaconda Cloud
-  schedule:
-    - cron: "34 2 * * *"
-  # Run on demand with workflow dispatch
-  workflow_dispatch:
-
-permissions:
-  actions: read
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  build_wheel:
-    name: Build and upload wheel
-    if: github.repository_owner == 'pybind'
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          fetch-depth: 0
-
-      - name: Install uv
-        uses: astral-sh/setup-uv@v7
-
-      - name: Build SDist and wheels
-        run: |
-          uv tool install nox
-          nox -s build
-          nox -s build_global
-
-      - uses: actions/upload-artifact@v5
-        with:
-          name: Packages
-          path: dist/*
-
-  upload_nightly_wheels:
-    name: Upload nightly wheels to Anaconda Cloud
-    if: github.repository_owner == 'pybind'
-    needs: [build_wheel]
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/download-artifact@v6
-        with:
-          name: Packages
-          path: dist
-
-      - name: List wheel to be deployed
-        run: ls -lha dist/*.whl
-
-      - name: Upload wheel to Anaconda Cloud as nightly
-        uses: scientific-python/upload-nightly-action@b36e8c0c10dbcfd2e05bf95f17ef8c14fd708dbf # 0.6.2
-        with:
-          artifacts_path: dist
-          anaconda_nightly_upload_token: ${{ secrets.ANACONDA_ORG_UPLOAD_TOKEN }}
diff --git a/.github/workflows/pip.yml b/.github/workflows/pip.yml
deleted file mode 100644
index 8df91a00fa..0000000000
--- a/.github/workflows/pip.yml
+++ /dev/null
@@ -1,118 +0,0 @@
-name: Pip
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-    - master
-    - stable
-    - v*
-  release:
-    types:
-    - published
-
-permissions:
-  contents: read
-
-jobs:
-  # This builds the sdists and wheels and makes sure the files are exactly as
-  # expected.
-  test-packaging:
-    name: 🐍 3.8 • 📦 tests • windows-latest
-    runs-on: windows-latest
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup 🐍 3.8
-      uses: actions/setup-python@v6
-      with:
-        python-version: 3.8
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-
-    - name: Prepare env
-      run: uv pip install --system -r tests/requirements.txt
-
-    - name: Python Packaging tests
-      run: pytest tests/extra_python_package/
-
-
-  # This runs the packaging tests and also builds and saves the packages as
-  # artifacts.
-  packaging:
-    name: 🐍 3.8 • 📦 & 📦 tests • ubuntu-latest
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup 🐍 3.8
-      uses: actions/setup-python@v6
-      with:
-        python-version: 3.8
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-
-    - name: Prepare env
-      run: uv pip install --system -r tests/requirements.txt twine nox
-
-    - name: Python Packaging tests
-      run: pytest tests/extra_python_package/
-
-    - name: Build SDist and wheels
-      run: |
-        nox -s build
-        nox -s build_global
-
-    - name: Check metadata
-      run: twine check dist/*
-
-    - name: Save standard package
-      uses: actions/upload-artifact@v5
-      with:
-        name: standard
-        path: dist/pybind11-*
-
-    - name: Save global package
-      uses: actions/upload-artifact@v5
-      with:
-        name: global
-        path: dist/*global-*
-
-
-
-  # When a GitHub release is made, upload the artifacts to PyPI
-  upload:
-    name: Upload to PyPI
-    runs-on: ubuntu-latest
-    if: github.event_name == 'release' && github.event.action == 'published'
-    needs: [packaging]
-    environment:
-      name: pypi
-      url: https://pypi.org/p/pybind11
-    permissions:
-      id-token: write
-      attestations: write
-
-    steps:
-    # Downloads all to directories matching the artifact names
-    - uses: actions/download-artifact@v6
-
-    - name: Generate artifact attestation for sdist and wheel
-      uses: actions/attest-build-provenance@v3
-      with:
-        subject-path: "*/pybind11*"
-
-    - name: Publish standard package
-      uses: pypa/gh-action-pypi-publish@release/v1
-      with:
-        packages-dir: standard/
-
-    - name: Publish global package
-      uses: pypa/gh-action-pypi-publish@release/v1
-      with:
-        packages-dir: global/
diff --git a/.github/workflows/tests-cibw.yml b/.github/workflows/tests-cibw.yml
deleted file mode 100644
index 5dfb5dc940..0000000000
--- a/.github/workflows/tests-cibw.yml
+++ /dev/null
@@ -1,95 +0,0 @@
-name: CIBW
-
-on:
-  workflow_dispatch:
-  pull_request:
-    branches:
-    - master
-    - stable
-    - v*
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  build-wasm-emscripten:
-    name: Pyodide wheel
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    - uses: pypa/cibuildwheel@v3.3
-      env:
-        PYODIDE_BUILD_EXPORTS: whole_archive
-      with:
-        package-dir: tests
-        only: cp312-pyodide_wasm32
-
-  build-ios:
-    name: iOS wheel ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-    strategy:
-      fail-fast: false
-      matrix:
-        runs-on: [macos-14, macos-15-intel]
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    # We have to uninstall first because GH is now using a local tap to build cmake<4, iOS needs cmake>=4
-    - run: brew uninstall cmake && brew install cmake
-
-    - uses: pypa/cibuildwheel@v3.3
-      env:
-        CIBW_PLATFORM: ios
-        CIBW_SKIP: cp314-*  # https://github.com/pypa/cibuildwheel/issues/2494
-      with:
-        package-dir: tests
-
-  build-android:
-    name: Android wheel ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-    strategy:
-      fail-fast: false
-      matrix:
-        runs-on: [macos-latest, macos-15-intel, ubuntu-latest]
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    # GitHub Actions can't currently run the Android emulator on macOS.
-    - name: Skip Android tests on macOS
-      if: contains(matrix.runs-on, 'macos')
-      run: echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
-
-    # Temporarily disable Android tests on ubuntu-latest due to emulator issues.
-    # See https://github.com/pybind/pybind11/pull/5914.
-    - name: "NOTE: Android tests are disabled on ubuntu-latest"
-      if: contains(matrix.runs-on, 'ubuntu')
-      run: |
-        echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
-        echo '::warning::Android cibuildwheel tests are disabled on ubuntu-latest (CIBW_TEST_COMMAND is empty). See PR 5914.'
-
-    # https://github.blog/changelog/2024-04-02-github-actions-hardware-accelerated-android-virtualization-now-available/
-    - name: Enable KVM for Android emulator
-      if: contains(matrix.runs-on, 'ubuntu')
-      run: |
-        echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
-        sudo udevadm control --reload-rules
-        sudo udevadm trigger --name-match=kvm
-
-    - run: pipx install patchelf
-
-    - uses: pypa/cibuildwheel@v3.3
-      env:
-        CIBW_PLATFORM: android
-      with:
-        package-dir: tests
diff --git a/.github/workflows/upstream.yml b/.github/workflows/upstream.yml
deleted file mode 100644
index 15ede7a856..0000000000
--- a/.github/workflows/upstream.yml
+++ /dev/null
@@ -1,116 +0,0 @@
-name: Upstream
-
-on:
-  workflow_dispatch:
-  pull_request:
-
-permissions:
-  contents: read
-
-concurrency:
-  group: upstream-${{ github.ref }}
-  cancel-in-progress: true
-
-env:
-  PIP_BREAK_SYSTEM_PACKAGES: 1
-  # For cmake:
-  VERBOSE: 1
-
-jobs:
-  standard:
-    name: "🐍 3.13 latest • ubuntu-latest • x64"
-    runs-on: ubuntu-latest
-    # Only runs when the  'python dev' label is selected
-    if: "contains(github.event.pull_request.labels.*.name, 'python dev')"
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python 3.13
-      uses: actions/setup-python@v6
-      with:
-        python-version: "3.13"
-        allow-prereleases: true
-
-    - name: Setup Boost
-      run: sudo apt-get install libboost-dev
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Run pip installs
-      run: |
-        python -m pip install --upgrade pip
-        python -m pip install -r tests/requirements.txt
-
-    - name: Show platform info
-      run: |
-        python -m platform
-        cmake --version
-        pip list
-
-    # First build - C++11 mode and inplace
-    - name: Configure C++11
-      run: >
-        cmake -S . -B build11
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=11
-        -DCMAKE_BUILD_TYPE=Debug
-
-    - name: Build C++11
-      run: cmake --build build11 -j 2
-
-    - name: Python tests C++11
-      run: cmake --build build11 --target pytest -j 2
-
-    - name: C++11 tests
-      run: cmake --build build11  --target cpptest -j 2
-
-    - name: Interface test C++11
-      run: cmake --build build11 --target test_cmake_build
-
-    # Second build - C++17 mode and in a build directory
-    - name: Configure C++17
-      run: >
-        cmake -S . -B build17
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=17
-
-    - name: Build C++17
-      run: cmake --build build17 -j 2
-
-    - name: Python tests C++17
-      run: cmake --build build17 --target pytest
-
-    - name: C++17 tests
-      run: cmake --build build17 --target cpptest
-
-    # Third build - C++17 mode with unstable ABI
-    - name: Configure (unstable ABI)
-      run: >
-        cmake -S . -B build17max
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=17
-        -DPYBIND11_INTERNALS_VERSION=10000000
-
-    - name: Build (unstable ABI)
-      run: cmake --build build17max -j 2
-
-    - name: Python tests (unstable ABI)
-      run: cmake --build build17max --target pytest
-
-    - name: Interface test (unstable ABI)
-      run: cmake --build build17max --target test_cmake_build
-
-    # This makes sure the setup_helpers module can build packages using
-    # setuptools
-    - name: Setuptools helpers test
-      run: |
-        pip install setuptools
-        pytest tests/extra_setuptools

From ed112926365544bfdb6d5153f8947474d8c4caf2 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 19:25:39 -0800
Subject: [PATCH 06/24] Temporarily disable AppVeyor builds via skip_commits

---
 .appveyor.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.appveyor.yml b/.appveyor.yml
index 391cf1071c..f1a0bf1048 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -2,6 +2,8 @@ version: 1.0.{build}
 image:
 - Visual Studio 2017
 test: off
+skip_commits:
+  message: /.*/  # Skip ALL commits.
 skip_branch_with_pr: true
 build:
   parallel: true

From ad3e1c34ceeb072c5812f385f38360387fbbcf68 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 20:21:35 -0800
Subject: [PATCH 07/24] Add DEBUG_LOOK in TEST_CASE("Move Subinterpreter")

---
 tests/test_with_catch/test_subinterpreter.cpp | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tests/test_with_catch/test_subinterpreter.cpp b/tests/test_with_catch/test_subinterpreter.cpp
index 3c7c35be19..466af4cd33 100644
--- a/tests/test_with_catch/test_subinterpreter.cpp
+++ b/tests/test_with_catch/test_subinterpreter.cpp
@@ -7,6 +7,7 @@
 PYBIND11_WARNING_DISABLE_MSVC(4996)
 
 #    include <catch.hpp>
+#    include <cstdio>
 #    include <cstdlib>
 #    include <fstream>
 #    include <functional>
@@ -16,6 +17,16 @@ PYBIND11_WARNING_DISABLE_MSVC(4996)
 namespace py = pybind11;
 using namespace py::literals;
 
+namespace {
+inline void debug_look(const char *file, int line) {
+    fflush(stderr);
+    std::fprintf(stdout, "\nLOOOK %s:%d\n", file, line);
+    fflush(stdout);
+}
+} // namespace
+
+#    define DEBUG_LOOK() debug_look(__FILE__, __LINE__)
+
 bool has_state_dict_internals_obj();
 uintptr_t get_details_as_uintptr();
 
@@ -92,30 +103,48 @@ TEST_CASE("Single Subinterpreter") {
 
 #    if PY_VERSION_HEX >= 0x030D0000
 TEST_CASE("Move Subinterpreter") {
+    DEBUG_LOOK();
     std::unique_ptr<py::subinterpreter> sub(new py::subinterpreter(py::subinterpreter::create()));
+    DEBUG_LOOK();
 
     // on this thread, use the subinterpreter and import some non-trivial junk
     {
+        DEBUG_LOOK();
         py::subinterpreter_scoped_activate activate(*sub);
+        DEBUG_LOOK();
 
         py::list(py::module_::import("sys").attr("path")).append(py::str("."));
+        DEBUG_LOOK();
         py::module_::import("datetime");
+        DEBUG_LOOK();
         py::module_::import("threading");
+        DEBUG_LOOK();
         py::module_::import("external_module");
+        DEBUG_LOOK();
     }
 
+    DEBUG_LOOK();
     std::thread([&]() {
+        DEBUG_LOOK();
         // Use it again
         {
+            DEBUG_LOOK();
             py::subinterpreter_scoped_activate activate(*sub);
+            DEBUG_LOOK();
             py::module_::import("external_module");
+            DEBUG_LOOK();
         }
+        DEBUG_LOOK();
         sub.reset();
+        DEBUG_LOOK();
     }).join();
+    DEBUG_LOOK();
 
     REQUIRE(!sub);
+    DEBUG_LOOK();
 
     unsafe_reset_internals_for_single_interpreter();
+    DEBUG_LOOK();
 }
 #    endif
 

From 48725893c63502ac0da8a10e608197eecf4d5f83 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 23:25:33 -0800
Subject: [PATCH 08/24] Add Python version banner to Catch progress reporter

Print the CPython version once at the start of the Catch-based
interpreter tests using Py_GetVersion(). This makes it trivial to
confirm which free-threaded build a failing run is using when
inspecting CI or local logs.
---
 tests/test_with_catch/catch.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/test_with_catch/catch.cpp b/tests/test_with_catch/catch.cpp
index aa5de2f3c5..171d1df626 100644
--- a/tests/test_with_catch/catch.cpp
+++ b/tests/test_with_catch/catch.cpp
@@ -21,6 +21,8 @@ namespace py = pybind11;
 // Simple progress reporter that prints a line per test case.
 namespace {
 
+bool g_printed_python_version = false;
+
 class ProgressReporter : public Catch::CumulativeReporterBase<ProgressReporter> {
 public:
     using CumulativeReporterBase::CumulativeReporterBase;
@@ -28,6 +30,12 @@ class ProgressReporter : public Catch::CumulativeReporterBase<ProgressReporter>
     static std::string getDescription() { return "Simple progress reporter (one line per test)"; }
 
     void testCaseStarting(Catch::TestCaseInfo const &testInfo) override {
+        if (!g_printed_python_version) {
+            g_printed_python_version = true;
+            const char *version = Py_GetVersion();
+            stream << "[ PYTHON   ] " << version << '\n';
+            stream.flush();
+        }
         stream << "[ RUN      ] " << testInfo.name << '\n';
         stream.flush();
         CumulativeReporterBase::testCaseStarting(testInfo);

From b13e218bfa2c2f6c7546f3e577385a3161caeb8d Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 23:26:04 -0800
Subject: [PATCH 09/24] Revert "Add DEBUG_LOOK in TEST_CASE("Move
 Subinterpreter")"

This reverts commit ad3e1c34ceeb072c5812f385f38360387fbbcf68.
---
 tests/test_with_catch/test_subinterpreter.cpp | 29 -------------------
 1 file changed, 29 deletions(-)

diff --git a/tests/test_with_catch/test_subinterpreter.cpp b/tests/test_with_catch/test_subinterpreter.cpp
index 466af4cd33..3c7c35be19 100644
--- a/tests/test_with_catch/test_subinterpreter.cpp
+++ b/tests/test_with_catch/test_subinterpreter.cpp
@@ -7,7 +7,6 @@
 PYBIND11_WARNING_DISABLE_MSVC(4996)
 
 #    include <catch.hpp>
-#    include <cstdio>
 #    include <cstdlib>
 #    include <fstream>
 #    include <functional>
@@ -17,16 +16,6 @@ PYBIND11_WARNING_DISABLE_MSVC(4996)
 namespace py = pybind11;
 using namespace py::literals;
 
-namespace {
-inline void debug_look(const char *file, int line) {
-    fflush(stderr);
-    std::fprintf(stdout, "\nLOOOK %s:%d\n", file, line);
-    fflush(stdout);
-}
-} // namespace
-
-#    define DEBUG_LOOK() debug_look(__FILE__, __LINE__)
-
 bool has_state_dict_internals_obj();
 uintptr_t get_details_as_uintptr();
 
@@ -103,48 +92,30 @@ TEST_CASE("Single Subinterpreter") {
 
 #    if PY_VERSION_HEX >= 0x030D0000
 TEST_CASE("Move Subinterpreter") {
-    DEBUG_LOOK();
     std::unique_ptr<py::subinterpreter> sub(new py::subinterpreter(py::subinterpreter::create()));
-    DEBUG_LOOK();
 
     // on this thread, use the subinterpreter and import some non-trivial junk
     {
-        DEBUG_LOOK();
         py::subinterpreter_scoped_activate activate(*sub);
-        DEBUG_LOOK();
 
         py::list(py::module_::import("sys").attr("path")).append(py::str("."));
-        DEBUG_LOOK();
         py::module_::import("datetime");
-        DEBUG_LOOK();
         py::module_::import("threading");
-        DEBUG_LOOK();
         py::module_::import("external_module");
-        DEBUG_LOOK();
     }
 
-    DEBUG_LOOK();
     std::thread([&]() {
-        DEBUG_LOOK();
         // Use it again
         {
-            DEBUG_LOOK();
             py::subinterpreter_scoped_activate activate(*sub);
-            DEBUG_LOOK();
             py::module_::import("external_module");
-            DEBUG_LOOK();
         }
-        DEBUG_LOOK();
         sub.reset();
-        DEBUG_LOOK();
     }).join();
-    DEBUG_LOOK();
 
     REQUIRE(!sub);
-    DEBUG_LOOK();
 
     unsafe_reset_internals_for_single_interpreter();
-    DEBUG_LOOK();
 }
 #    endif
 

From 5281e1c20c7477878df53fd6a09395f8bb6dcc09 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sat, 13 Dec 2025 23:27:51 -0800
Subject: [PATCH 10/24] Pin CI free-threaded runs to CPython 3.14.0t

Update the standard-small and standard-large GitHub Actions jobs to
request python-version 3.14.0t instead of 3.14t. This forces setup-python
to use the last-known-good 3.14.0 free-threaded build rather than the
newer 3.14.1+ builds where subinterpreter finalization regressed.
---
 .github/workflows/ci.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0653b2adcd..f51b734a1b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,7 +36,7 @@ jobs:
       matrix:
         include:
           - runs-on: ubuntu-latest
-            python-version: '3.14t'
+            python-version: '3.14.0t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
 
 
@@ -54,10 +54,10 @@ jobs:
       matrix:
         include:
           - runs-on: macos-latest
-            python-version: '3.14t'
+            python-version: '3.14.0t'
             cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: windows-latest
-            python-version: '3.14t'
+            python-version: '3.14.0t'
             cmake-args: -DCMAKE_CXX_STANDARD=23
 
     name: 🐍

From 8f4753ee78c6d122e3572445b8df5bb65dc24ba3 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 06:54:38 -0800
Subject: [PATCH 11/24] Revert "Pin CI free-threaded runs to CPython 3.14.0t"

This reverts commit 5281e1c20c7477878df53fd6a09395f8bb6dcc09.
---
 .github/workflows/ci.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f51b734a1b..0653b2adcd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,7 +36,7 @@ jobs:
       matrix:
         include:
           - runs-on: ubuntu-latest
-            python-version: '3.14.0t'
+            python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
 
 
@@ -54,10 +54,10 @@ jobs:
       matrix:
         include:
           - runs-on: macos-latest
-            python-version: '3.14.0t'
+            python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: windows-latest
-            python-version: '3.14.0t'
+            python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=23
 
     name: 🐍

From f1d349b98fe9108af94d7ce2fe73a6ffcfcb6297 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 06:54:56 -0800
Subject: [PATCH 12/24] Revert "Temporarily disable AppVeyor builds via
 skip_commits"

This reverts commit ed112926365544bfdb6d5153f8947474d8c4caf2.
---
 .appveyor.yml | 2 --
 1 file changed, 2 deletions(-)

diff --git a/.appveyor.yml b/.appveyor.yml
index f1a0bf1048..391cf1071c 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -2,8 +2,6 @@ version: 1.0.{build}
 image:
 - Visual Studio 2017
 test: off
-skip_commits:
-  message: /.*/  # Skip ALL commits.
 skip_branch_with_pr: true
 build:
   parallel: true

From 35472e5706891f5946c48ac7f6630d97aab6665f Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 06:55:13 -0800
Subject: [PATCH 13/24] Revert "Temporarily remove non-CI GitHub workflow
 files"

This reverts commit 0fe6a42a0406f32178429fa8b50de206b6db37d2.
---
 .github/workflows/configure.yml  |  85 ++++++++++++++++++++++
 .github/workflows/docs-link.yml  |  41 +++++++++++
 .github/workflows/format.yml     |  54 ++++++++++++++
 .github/workflows/labeler.yml    |  25 +++++++
 .github/workflows/nightlies.yml  |  59 ++++++++++++++++
 .github/workflows/pip.yml        | 118 +++++++++++++++++++++++++++++++
 .github/workflows/tests-cibw.yml |  95 +++++++++++++++++++++++++
 .github/workflows/upstream.yml   | 116 ++++++++++++++++++++++++++++++
 8 files changed, 593 insertions(+)
 create mode 100644 .github/workflows/configure.yml
 create mode 100644 .github/workflows/docs-link.yml
 create mode 100644 .github/workflows/format.yml
 create mode 100644 .github/workflows/labeler.yml
 create mode 100644 .github/workflows/nightlies.yml
 create mode 100644 .github/workflows/pip.yml
 create mode 100644 .github/workflows/tests-cibw.yml
 create mode 100644 .github/workflows/upstream.yml

diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
new file mode 100644
index 0000000000..cd034c883f
--- /dev/null
+++ b/.github/workflows/configure.yml
@@ -0,0 +1,85 @@
+name: Config
+
+on:
+  workflow_dispatch:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - ready_for_review
+  push:
+    branches:
+      - master
+      - stable
+      - v*
+
+permissions:
+  contents: read
+
+jobs:
+  # This tests various versions of CMake in various combinations, to make sure
+  # the configure step passes.
+  cmake:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - runs-on: ubuntu-22.04
+          cmake: "3.15"
+
+        - runs-on: ubuntu-24.04
+          cmake: "3.26"
+
+        - runs-on: ubuntu-24.04
+          cmake: "3.29"
+
+        - runs-on: macos-15-intel
+          cmake: "3.15"
+
+        - runs-on: macos-14
+          cmake: "4.0"
+
+        - runs-on: windows-latest
+          cmake: "4.0"
+
+    name: 🐍 3.11 • CMake ${{ matrix.cmake }} • ${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python 3.11
+      uses: actions/setup-python@v6
+      with:
+        python-version: 3.11
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+
+    - name: Prepare env
+      run: uv pip install --python=python --system -r tests/requirements.txt
+
+    # An action for adding a specific version of CMake:
+    #   https://github.com/jwlawson/actions-setup-cmake
+    - name: Setup CMake ${{ matrix.cmake }}
+      uses: jwlawson/actions-setup-cmake@v2.0
+      with:
+        cmake-version: ${{ matrix.cmake }}
+
+    # These steps use a directory with a space in it intentionally
+    - name: Configure
+      shell: bash
+      run: cmake -S. -B"build dir" -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+
+    # Only build and test if this was manually triggered in the GitHub UI
+    - name: Build
+      working-directory: build dir
+      if: github.event_name == 'workflow_dispatch'
+      run: cmake --build . --config Release
+
+    - name: Test
+      working-directory: build dir
+      if: github.event_name == 'workflow_dispatch'
+      run: cmake --build . --config Release --target check
diff --git a/.github/workflows/docs-link.yml b/.github/workflows/docs-link.yml
new file mode 100644
index 0000000000..ea25410cb9
--- /dev/null
+++ b/.github/workflows/docs-link.yml
@@ -0,0 +1,41 @@
+name: Read the Docs PR preview
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - synchronize
+
+permissions:
+  contents: read
+  pull-requests: write
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  documentation-links:
+    runs-on: ubuntu-latest
+    if: github.event.repository.fork == false
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Check for docs changes
+        id: docs_changes
+        run: |
+          # Fetch the PR head
+          git fetch origin pull/${{ github.event.pull_request.number }}/head:pr-head
+
+          # Show diff between base (current checkout) and PR head
+          if git diff --name-only HEAD pr-head | grep -q '^docs/'; then
+            echo "docs_changed=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "docs_changed=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - uses: readthedocs/actions/preview@v1
+        if: steps.docs_changes.outputs.docs_changed == 'true'
+        with:
+          project-slug: "pybind11"
+          single-version: "true"
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
new file mode 100644
index 0000000000..6bf77324a9
--- /dev/null
+++ b/.github/workflows/format.yml
@@ -0,0 +1,54 @@
+# This is a format job. Pre-commit has a first-party GitHub action, so we use
+# that: https://github.com/pre-commit/action
+
+name: Format
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+    - master
+    - stable
+    - "v*"
+
+permissions:
+  contents: read
+
+env:
+  FORCE_COLOR: 3
+  # For cmake:
+  VERBOSE: 1
+
+jobs:
+  pre-commit:
+    name: Format
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6
+    - uses: actions/setup-python@v6
+      with:
+        python-version: "3.x"
+    - name: Add matchers
+      run: echo "::add-matcher::$GITHUB_WORKSPACE/.github/matchers/pylint.json"
+    - uses: pre-commit/action@v3.0.1
+
+  clang-tidy:
+    # When making changes here, please also review the "Clang-Tidy" section
+    # in .github/CONTRIBUTING.md and update as needed.
+    name: Clang-Tidy
+    runs-on: ubuntu-latest
+    container: silkeh/clang:20
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Install requirements
+      run: apt-get update && apt-get install -y git python3-dev python3-pytest ninja-build
+
+    - name: Configure
+      run: cmake --preset tidy
+    - name: Build
+      run: cmake --build --preset tidy
+
+    - name: Embedded
+      run: cmake --build --preset tidy -t cpptest
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
new file mode 100644
index 0000000000..f5b618ba82
--- /dev/null
+++ b/.github/workflows/labeler.yml
@@ -0,0 +1,25 @@
+name: Labeler
+on:
+  pull_request_target:
+    types: [closed]
+
+permissions: {}
+
+jobs:
+  label:
+    name: Labeler
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+
+    - uses: actions/labeler@v6
+      if: >
+        github.event.pull_request.merged == true &&
+        !startsWith(github.event.pull_request.title, 'chore(deps):') &&
+        !startsWith(github.event.pull_request.title, 'ci(fix):') &&
+        !startsWith(github.event.pull_request.title, 'docs(changelog):')
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        configuration-path: .github/labeler_merged.yml
diff --git a/.github/workflows/nightlies.yml b/.github/workflows/nightlies.yml
new file mode 100644
index 0000000000..ad4a351521
--- /dev/null
+++ b/.github/workflows/nightlies.yml
@@ -0,0 +1,59 @@
+name: Upload nightly wheels to Anaconda Cloud
+
+on:
+  # Run daily at 2:34 UTC to upload nightly wheels to Anaconda Cloud
+  schedule:
+    - cron: "34 2 * * *"
+  # Run on demand with workflow dispatch
+  workflow_dispatch:
+
+permissions:
+  actions: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build_wheel:
+    name: Build and upload wheel
+    if: github.repository_owner == 'pybind'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v7
+
+      - name: Build SDist and wheels
+        run: |
+          uv tool install nox
+          nox -s build
+          nox -s build_global
+
+      - uses: actions/upload-artifact@v5
+        with:
+          name: Packages
+          path: dist/*
+
+  upload_nightly_wheels:
+    name: Upload nightly wheels to Anaconda Cloud
+    if: github.repository_owner == 'pybind'
+    needs: [build_wheel]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/download-artifact@v6
+        with:
+          name: Packages
+          path: dist
+
+      - name: List wheel to be deployed
+        run: ls -lha dist/*.whl
+
+      - name: Upload wheel to Anaconda Cloud as nightly
+        uses: scientific-python/upload-nightly-action@b36e8c0c10dbcfd2e05bf95f17ef8c14fd708dbf # 0.6.2
+        with:
+          artifacts_path: dist
+          anaconda_nightly_upload_token: ${{ secrets.ANACONDA_ORG_UPLOAD_TOKEN }}
diff --git a/.github/workflows/pip.yml b/.github/workflows/pip.yml
new file mode 100644
index 0000000000..8df91a00fa
--- /dev/null
+++ b/.github/workflows/pip.yml
@@ -0,0 +1,118 @@
+name: Pip
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+    - master
+    - stable
+    - v*
+  release:
+    types:
+    - published
+
+permissions:
+  contents: read
+
+jobs:
+  # This builds the sdists and wheels and makes sure the files are exactly as
+  # expected.
+  test-packaging:
+    name: 🐍 3.8 • 📦 tests • windows-latest
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup 🐍 3.8
+      uses: actions/setup-python@v6
+      with:
+        python-version: 3.8
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+
+    - name: Prepare env
+      run: uv pip install --system -r tests/requirements.txt
+
+    - name: Python Packaging tests
+      run: pytest tests/extra_python_package/
+
+
+  # This runs the packaging tests and also builds and saves the packages as
+  # artifacts.
+  packaging:
+    name: 🐍 3.8 • 📦 & 📦 tests • ubuntu-latest
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup 🐍 3.8
+      uses: actions/setup-python@v6
+      with:
+        python-version: 3.8
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+
+    - name: Prepare env
+      run: uv pip install --system -r tests/requirements.txt twine nox
+
+    - name: Python Packaging tests
+      run: pytest tests/extra_python_package/
+
+    - name: Build SDist and wheels
+      run: |
+        nox -s build
+        nox -s build_global
+
+    - name: Check metadata
+      run: twine check dist/*
+
+    - name: Save standard package
+      uses: actions/upload-artifact@v5
+      with:
+        name: standard
+        path: dist/pybind11-*
+
+    - name: Save global package
+      uses: actions/upload-artifact@v5
+      with:
+        name: global
+        path: dist/*global-*
+
+
+
+  # When a GitHub release is made, upload the artifacts to PyPI
+  upload:
+    name: Upload to PyPI
+    runs-on: ubuntu-latest
+    if: github.event_name == 'release' && github.event.action == 'published'
+    needs: [packaging]
+    environment:
+      name: pypi
+      url: https://pypi.org/p/pybind11
+    permissions:
+      id-token: write
+      attestations: write
+
+    steps:
+    # Downloads all to directories matching the artifact names
+    - uses: actions/download-artifact@v6
+
+    - name: Generate artifact attestation for sdist and wheel
+      uses: actions/attest-build-provenance@v3
+      with:
+        subject-path: "*/pybind11*"
+
+    - name: Publish standard package
+      uses: pypa/gh-action-pypi-publish@release/v1
+      with:
+        packages-dir: standard/
+
+    - name: Publish global package
+      uses: pypa/gh-action-pypi-publish@release/v1
+      with:
+        packages-dir: global/
diff --git a/.github/workflows/tests-cibw.yml b/.github/workflows/tests-cibw.yml
new file mode 100644
index 0000000000..5dfb5dc940
--- /dev/null
+++ b/.github/workflows/tests-cibw.yml
@@ -0,0 +1,95 @@
+name: CIBW
+
+on:
+  workflow_dispatch:
+  pull_request:
+    branches:
+    - master
+    - stable
+    - v*
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build-wasm-emscripten:
+    name: Pyodide wheel
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+        fetch-depth: 0
+
+    - uses: pypa/cibuildwheel@v3.3
+      env:
+        PYODIDE_BUILD_EXPORTS: whole_archive
+      with:
+        package-dir: tests
+        only: cp312-pyodide_wasm32
+
+  build-ios:
+    name: iOS wheel ${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        runs-on: [macos-14, macos-15-intel]
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+        fetch-depth: 0
+
+    # We have to uninstall first because GH is now using a local tap to build cmake<4, iOS needs cmake>=4
+    - run: brew uninstall cmake && brew install cmake
+
+    - uses: pypa/cibuildwheel@v3.3
+      env:
+        CIBW_PLATFORM: ios
+        CIBW_SKIP: cp314-*  # https://github.com/pypa/cibuildwheel/issues/2494
+      with:
+        package-dir: tests
+
+  build-android:
+    name: Android wheel ${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        runs-on: [macos-latest, macos-15-intel, ubuntu-latest]
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+        fetch-depth: 0
+
+    # GitHub Actions can't currently run the Android emulator on macOS.
+    - name: Skip Android tests on macOS
+      if: contains(matrix.runs-on, 'macos')
+      run: echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
+
+    # Temporarily disable Android tests on ubuntu-latest due to emulator issues.
+    # See https://github.com/pybind/pybind11/pull/5914.
+    - name: "NOTE: Android tests are disabled on ubuntu-latest"
+      if: contains(matrix.runs-on, 'ubuntu')
+      run: |
+        echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
+        echo '::warning::Android cibuildwheel tests are disabled on ubuntu-latest (CIBW_TEST_COMMAND is empty). See PR 5914.'
+
+    # https://github.blog/changelog/2024-04-02-github-actions-hardware-accelerated-android-virtualization-now-available/
+    - name: Enable KVM for Android emulator
+      if: contains(matrix.runs-on, 'ubuntu')
+      run: |
+        echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+        sudo udevadm control --reload-rules
+        sudo udevadm trigger --name-match=kvm
+
+    - run: pipx install patchelf
+
+    - uses: pypa/cibuildwheel@v3.3
+      env:
+        CIBW_PLATFORM: android
+      with:
+        package-dir: tests
diff --git a/.github/workflows/upstream.yml b/.github/workflows/upstream.yml
new file mode 100644
index 0000000000..15ede7a856
--- /dev/null
+++ b/.github/workflows/upstream.yml
@@ -0,0 +1,116 @@
+name: Upstream
+
+on:
+  workflow_dispatch:
+  pull_request:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: upstream-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PIP_BREAK_SYSTEM_PACKAGES: 1
+  # For cmake:
+  VERBOSE: 1
+
+jobs:
+  standard:
+    name: "🐍 3.13 latest • ubuntu-latest • x64"
+    runs-on: ubuntu-latest
+    # Only runs when the  'python dev' label is selected
+    if: "contains(github.event.pull_request.labels.*.name, 'python dev')"
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python 3.13
+      uses: actions/setup-python@v6
+      with:
+        python-version: "3.13"
+        allow-prereleases: true
+
+    - name: Setup Boost
+      run: sudo apt-get install libboost-dev
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Run pip installs
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install -r tests/requirements.txt
+
+    - name: Show platform info
+      run: |
+        python -m platform
+        cmake --version
+        pip list
+
+    # First build - C++11 mode and inplace
+    - name: Configure C++11
+      run: >
+        cmake -S . -B build11
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=11
+        -DCMAKE_BUILD_TYPE=Debug
+
+    - name: Build C++11
+      run: cmake --build build11 -j 2
+
+    - name: Python tests C++11
+      run: cmake --build build11 --target pytest -j 2
+
+    - name: C++11 tests
+      run: cmake --build build11  --target cpptest -j 2
+
+    - name: Interface test C++11
+      run: cmake --build build11 --target test_cmake_build
+
+    # Second build - C++17 mode and in a build directory
+    - name: Configure C++17
+      run: >
+        cmake -S . -B build17
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=17
+
+    - name: Build C++17
+      run: cmake --build build17 -j 2
+
+    - name: Python tests C++17
+      run: cmake --build build17 --target pytest
+
+    - name: C++17 tests
+      run: cmake --build build17 --target cpptest
+
+    # Third build - C++17 mode with unstable ABI
+    - name: Configure (unstable ABI)
+      run: >
+        cmake -S . -B build17max
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=17
+        -DPYBIND11_INTERNALS_VERSION=10000000
+
+    - name: Build (unstable ABI)
+      run: cmake --build build17max -j 2
+
+    - name: Python tests (unstable ABI)
+      run: cmake --build build17max --target pytest
+
+    - name: Interface test (unstable ABI)
+      run: cmake --build build17max --target test_cmake_build
+
+    # This makes sure the setup_helpers module can build packages using
+    # setuptools
+    - name: Setuptools helpers test
+      run: |
+        pip install setuptools
+        pytest tests/extra_setuptools

From fd07d33685b278def31af70ffb85bc8da10ad36f Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 06:55:31 -0800
Subject: [PATCH 14/24] Revert "Temporarily limit CI to Python 3.14t
 free-threading jobs"

This reverts commit 60ae0e8f744904ba2499cf44a43fdf91049f6e4a.
---
 .github/workflows/ci.yml | 131 +++++++++++++++++++++++++++++++++------
 1 file changed, 113 insertions(+), 18 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0653b2adcd..d00ee6d27e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,9 +35,27 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - runs-on: ubuntu-22.04
+            python-version: '3.8'
+            cmake-args: -DPYBIND11_FINDPYTHON=OFF -DPYBIND11_NUMPY_1_ONLY=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.13'
+            cmake-args: -DCMAKE_CXX_STANDARD=23 -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
           - runs-on: ubuntu-latest
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
+          - runs-on: ubuntu-latest
+            python-version: 'pypy3.11'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: 'graalpy-24.2'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: macos-latest
+            python-version: '3.14'
+            cmake-args: -DCMAKE_CXX_STANDARD=14
+          - runs-on: windows-2022
+            python-version: '3.8'
+            cmake-args: -DPYBIND11_FINDPYTHON=OFF
 
 
     name: 🐍
@@ -53,12 +71,90 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - runs-on: ubuntu-latest
+            python-version: '3.8'
+            cmake-args: -DPYBIND11_FINDPYTHON=ON -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: '3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: ubuntu-latest
+            python-version: '3.11'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: '3.12'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.13t'
+            cmake-args: -DCMAKE_CXX_STANDARD=20 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.14'
+            cmake-args: -DCMAKE_CXX_STANDARD=14 -DCMAKE_CXX_FLAGS="-DPYBIND11_HAS_SUBINTERPRETER_SUPPORT=0"
+          - runs-on: ubuntu-latest
+            python-version: 'pypy-3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=14
+          - runs-on: ubuntu-latest
+            python-version: 'graalpy-24.1'
+
+          # No SciPy for macOS ARM
+          - runs-on: macos-15-intel
+            python-version: '3.8'
+            cmake-args: -DCMAKE_CXX_STANDARD=14
+          - runs-on: macos-15-intel
+            python-version: '3.11'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
+          - runs-on: macos-latest
+            python-version: '3.12'
+            cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
+          - runs-on: macos-15-intel
+            python-version: '3.13t'
+            cmake-args: -DCMAKE_CXX_STANDARD=11
           - runs-on: macos-latest
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: macos-15-intel
+            python-version: 'pypy-3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: macos-latest
+            python-version: 'pypy-3.11'
+          - runs-on: macos-latest
+            python-version: 'graalpy-24.2'
+
+          - runs-on: windows-latest
+            python-version: '3.9'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
+          - runs-on: windows-2022
+            python-version: '3.8'
+            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DPYBIND11_NUMPY_1_ONLY=ON
+          - runs-on: windows-2022
+            python-version: '3.9'
+            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDLL -DCMAKE_CXX_STANDARD=14
+          # This needs a python built with MTd
+          # - runs-on: windows-2022
+          #   python-version: '3.11'
+          #   cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebug
+          - runs-on: windows-2022
+            python-version: '3.10'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_FLAGS="/GR /EHsc"
+          - runs-on: windows-2022
+            python-version: '3.13'
+            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebugDLL
+          - runs-on: windows-latest
+            python-version: '3.13t'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: windows-latest
+            python-version: '3.14'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: windows-latest
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=23
+          - runs-on: windows-latest
+            python-version: 'pypy-3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: windows-latest
+            python-version: 'pypy3.11'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          # The setup-python action currently doesn't have graalpy for windows
+          # See https://github.com/actions/setup-python/pull/880
 
     name: 🐍
     uses: ./.github/workflows/reusable-standard.yml
@@ -69,7 +165,7 @@ jobs:
 
   # This checks inplace builds with C++11
   inplace:
-    if: false
+    if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
       matrix:
@@ -144,7 +240,7 @@ jobs:
 
   manylinux:
     name: Manylinux on 🐍 3.13t • GIL
-    if: false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     timeout-minutes: 40
     container: quay.io/pypa/musllinux_1_2_x86_64:latest
@@ -169,7 +265,7 @@ jobs:
         run: cmake --build --preset testsvenv -t pytest
 
   deadsnakes:
-    if: false
+    if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
       matrix:
@@ -250,7 +346,7 @@ jobs:
 
   # Testing on clang using the excellent silkeh clang docker images
   clang:
-    if: false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -307,7 +403,6 @@ jobs:
 
   # Testing NVCC; forces sources to behave like .cu files
   cuda:
-    if: false
     runs-on: ubuntu-latest
     name: "🐍 3.10 • CUDA 12.2 • Ubuntu 22.04"
     container: nvidia/cuda:12.2.0-devel-ubuntu22.04
@@ -376,7 +471,7 @@ jobs:
 
   # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
-    if: false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-22.04
     name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
@@ -431,7 +526,7 @@ jobs:
 
   # Testing on GCC using the GCC docker images (only recent images supported)
   gcc:
-    if: false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -504,7 +599,7 @@ jobs:
 
   # Testing on ICC using the oneAPI apt repo
   icc:
-    if: false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-22.04
     timeout-minutes: 90
 
@@ -610,7 +705,7 @@ jobs:
 
   # Testing on CentOS (manylinux uses a centos base).
   centos:
-    if: false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
@@ -676,7 +771,7 @@ jobs:
 
   # This tests an "install" with the CMake tools
   install-classic:
-    if: false
+    if: github.event.pull_request.draft == false
     name: "🐍 3.9 • Debian • x86 •  Install"
     runs-on: ubuntu-latest
     container: i386/debian:bullseye
@@ -722,7 +817,7 @@ jobs:
   # This verifies that the documentation is not horribly broken, and does a
   # basic validation check on the SDist.
   doxygen:
-    if: false
+    if: github.event.pull_request.draft == false
     name: "Documentation build test"
     runs-on: ubuntu-latest
     timeout-minutes: 90
@@ -758,7 +853,7 @@ jobs:
         diff -rq $installed ./pybind11
 
   win32:
-    if: false
+    if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
       matrix:
@@ -813,7 +908,7 @@ jobs:
       run: cmake --build build -t pytest
 
   win32-debug:
-    if: false
+    if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
       matrix:
@@ -865,7 +960,7 @@ jobs:
 
 
   windows-2022:
-    if: false
+    if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
       matrix:
@@ -929,7 +1024,7 @@ jobs:
       run: cmake --build build_partial --target pytest
 
   mingw:
-    if: false
+    if: github.event.pull_request.draft == false
     name: "🐍 3 • windows-latest • ${{ matrix.sys }}"
     runs-on: windows-latest
     timeout-minutes: 90
@@ -1038,7 +1133,7 @@ jobs:
       run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cross_module_rtti
 
   windows_clang:
-    if: false
+    if: github.event.pull_request.draft == false
 
     strategy:
       matrix:
@@ -1113,7 +1208,7 @@ jobs:
 
   # Clang with MSVC/Windows SDK toolchain + python.org CPython (Windows ARM)
   windows_arm_clang_msvc:
-    if: false
+    if: github.event.pull_request.draft == false
 
     strategy:
       fail-fast: false
@@ -1172,7 +1267,7 @@ jobs:
 
   # Clang in MSYS2/MinGW-w64 CLANGARM64 toolchain + MSYS2 Python (Windows ARM)
   windows_arm_clang_msys2:
-    if: false
+    if: github.event.pull_request.draft == false
 
     strategy:
       fail-fast: false

From c8880a9b0fdd3dc071cb17724fc449bda0b8c167 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 06:57:21 -0800
Subject: [PATCH 15/24] Pin CI free-threaded runs to CPython 3.14.0t

Update the standard-small and standard-large GitHub Actions jobs to
request python-version 3.14.0t instead of 3.14t. This forces setup-python
to use the last-known-good 3.14.0 free-threaded build rather than the
newer 3.14.1+ builds where subinterpreter finalization regressed.
---
 .github/workflows/ci.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d00ee6d27e..ac0a7000e5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -42,7 +42,7 @@ jobs:
             python-version: '3.13'
             cmake-args: -DCMAKE_CXX_STANDARD=23 -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
           - runs-on: ubuntu-latest
-            python-version: '3.14t'
+            python-version: '3.14.0t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
           - runs-on: ubuntu-latest
             python-version: 'pypy3.11'
@@ -109,7 +109,7 @@ jobs:
             python-version: '3.13t'
             cmake-args: -DCMAKE_CXX_STANDARD=11
           - runs-on: macos-latest
-            python-version: '3.14t'
+            python-version: '3.14.0t'
             cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: macos-15-intel
             python-version: 'pypy-3.10'
@@ -145,7 +145,7 @@ jobs:
             python-version: '3.14'
             cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: windows-latest
-            python-version: '3.14t'
+            python-version: '3.14.0t'
             cmake-args: -DCMAKE_CXX_STANDARD=23
           - runs-on: windows-latest
             python-version: 'pypy-3.10'

From f84c9eb35701cd28d77cf51408229c6147121fa1 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 08:43:31 -0800
Subject: [PATCH 16/24] Switch NVHPC job to ubuntu-24.04 and disable AppVeyor

---
 .appveyor.yml            |    2 +
 .github/workflows/ci.yml | 1277 +++-----------------------------------
 2 files changed, 82 insertions(+), 1197 deletions(-)

diff --git a/.appveyor.yml b/.appveyor.yml
index 391cf1071c..833ec0e60a 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -2,6 +2,8 @@ version: 1.0.{build}
 image:
 - Visual Studio 2017
 test: off
+skip_commits:
+  message: /.*/ # Skip ALL commits.
 skip_branch_with_pr: true
 build:
   parallel: true
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ac0a7000e5..96c489f075 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,71 +1,18 @@
 name: CI
 
 on:
-  workflow_dispatch:
+  push:
+    branches:
+      - master
+      - main
   pull_request:
-    types:
-      - opened
-      - synchronize
-      - reopened
-      - ready_for_review
-
-permissions: read-all
-
-concurrency:
-  group: test-${{ github.ref }}
-  cancel-in-progress: true
+  workflow_dispatch:
 
-env:
-  PYTHONDEVMODE: 1
-  PIP_BREAK_SYSTEM_PACKAGES: 1
-  PIP_ONLY_BINARY: numpy
-  FORCE_COLOR: 3
-  PYTEST_TIMEOUT: 300
-  # For cmake:
-  VERBOSE: 1
-  CMAKE_COLOR_DIAGNOSTICS: 1
+permissions:
+  contents: read
 
 jobs:
-  # This is the "main" test suite, which tests a large number of different
-  # versions of default compilers and Python versions in GitHub Actions.
-  # It is in two parts: one that always runs, and one that runs on non-draft
   standard-small:
-    if: github.event.action != 'ready_for_review'
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - runs-on: ubuntu-22.04
-            python-version: '3.8'
-            cmake-args: -DPYBIND11_FINDPYTHON=OFF -DPYBIND11_NUMPY_1_ONLY=ON
-          - runs-on: ubuntu-latest
-            python-version: '3.13'
-            cmake-args: -DCMAKE_CXX_STANDARD=23 -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
-          - runs-on: ubuntu-latest
-            python-version: '3.14.0t'
-            cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
-          - runs-on: ubuntu-latest
-            python-version: 'pypy3.11'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: ubuntu-latest
-            python-version: 'graalpy-24.2'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
-          - runs-on: macos-latest
-            python-version: '3.14'
-            cmake-args: -DCMAKE_CXX_STANDARD=14
-          - runs-on: windows-2022
-            python-version: '3.8'
-            cmake-args: -DPYBIND11_FINDPYTHON=OFF
-
-
-    name: 🐍
-    uses: ./.github/workflows/reusable-standard.yml
-    with:
-      runs-on: ${{ matrix.runs-on }}
-      python-version: ${{ matrix.python-version }}
-      cmake-args: ${{ matrix.cmake-args }}
-
-  standard-large:
     if: github.event.pull_request.draft == false
     strategy:
       fail-fast: false
@@ -73,411 +20,159 @@ jobs:
         include:
           - runs-on: ubuntu-latest
             python-version: '3.8'
-            cmake-args: -DPYBIND11_FINDPYTHON=ON -DCMAKE_CXX_STANDARD=17
+            cxx_standard: 17
+          - runs-on: ubuntu-latest
+            python-version: '3.9'
+            cxx_standard: 17
           - runs-on: ubuntu-latest
             python-version: '3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
+            cxx_standard: 17
           - runs-on: ubuntu-latest
             python-version: '3.11'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_STANDARD=17
+            cxx_standard: 17
           - runs-on: ubuntu-latest
             python-version: '3.12'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
-          - runs-on: ubuntu-latest
-            python-version: '3.13t'
-            cmake-args: -DCMAKE_CXX_STANDARD=20 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
+            cxx_standard: 20
           - runs-on: ubuntu-latest
-            python-version: '3.14'
-            cmake-args: -DCMAKE_CXX_STANDARD=14 -DCMAKE_CXX_FLAGS="-DPYBIND11_HAS_SUBINTERPRETER_SUPPORT=0"
-          - runs-on: ubuntu-latest
-            python-version: 'pypy-3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=14
+            python-version: '3.13'
+            cxx_standard: 20
           - runs-on: ubuntu-latest
-            python-version: 'graalpy-24.1'
-
-          # No SciPy for macOS ARM
-          - runs-on: macos-15-intel
-            python-version: '3.8'
-            cmake-args: -DCMAKE_CXX_STANDARD=14
-          - runs-on: macos-15-intel
-            python-version: '3.11'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
-          - runs-on: macos-latest
-            python-version: '3.12'
-            cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
-          - runs-on: macos-15-intel
-            python-version: '3.13t'
-            cmake-args: -DCMAKE_CXX_STANDARD=11
-          - runs-on: macos-latest
             python-version: '3.14.0t'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
-          - runs-on: macos-15-intel
-            python-version: 'pypy-3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
+            cxx_standard: 20
           - runs-on: macos-latest
-            python-version: 'pypy-3.11'
+            python-version: '3.13'
+            cxx_standard: 17
           - runs-on: macos-latest
-            python-version: 'graalpy-24.2'
-
+            python-version: '3.14.0t'
+            cxx_standard: 23
           - runs-on: windows-latest
-            python-version: '3.9'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
-          - runs-on: windows-2022
-            python-version: '3.8'
-            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DPYBIND11_NUMPY_1_ONLY=ON
-          - runs-on: windows-2022
-            python-version: '3.9'
-            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDLL -DCMAKE_CXX_STANDARD=14
-          # This needs a python built with MTd
-          # - runs-on: windows-2022
-          #   python-version: '3.11'
-          #   cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebug
-          - runs-on: windows-2022
-            python-version: '3.10'
-            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_FLAGS="/GR /EHsc"
-          - runs-on: windows-2022
             python-version: '3.13'
-            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebugDLL
-          - runs-on: windows-latest
-            python-version: '3.13t'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: windows-latest
-            python-version: '3.14'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
+            cxx_standard: 17
           - runs-on: windows-latest
             python-version: '3.14.0t'
-            cmake-args: -DCMAKE_CXX_STANDARD=23
-          - runs-on: windows-latest
-            python-version: 'pypy-3.10'
-            cmake-args: -DCMAKE_CXX_STANDARD=17
-          - runs-on: windows-latest
-            python-version: 'pypy3.11'
-            cmake-args: -DCMAKE_CXX_STANDARD=20
-          # The setup-python action currently doesn't have graalpy for windows
-          # See https://github.com/actions/setup-python/pull/880
-
-    name: 🐍
-    uses: ./.github/workflows/reusable-standard.yml
-    with:
-      runs-on: ${{ matrix.runs-on }}
-      python-version: ${{ matrix.python-version }}
-      cmake-args: ${{ matrix.cmake-args }}
-
-  # This checks inplace builds with C++11
-  inplace:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - runs-on: ubuntu-latest
-            python-version: '3.9'
-          - runs-on: macos-latest
-            python-version: '3.12'
-          - runs-on: windows-latest
-            python-version: '3.11'
+            cxx_standard: 23
 
-    name: "🐍 ${{ matrix.python-version }} • ${{ matrix.runs-on }} • x64 inplace C++14"
+    name: "🐍 ${{ matrix.python-version }} • C++${{ matrix.cxx_standard }} • ${{ matrix.runs-on }}"
     runs-on: ${{ matrix.runs-on }}
     timeout-minutes: 90
 
+    env:
+      PYTHONDEVMODE: 1
+      PIP_BREAK_SYSTEM_PACKAGES: 1
+      PIP_ONLY_BINARY: numpy
+      FORCE_COLOR: 3
+      PYTEST_TIMEOUT: 300
+      VERBOSE: 1
+      CMAKE_COLOR_DIAGNOSTICS: 1
+
     steps:
     - uses: actions/checkout@v6
 
-    - name: Setup Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v6
+    - uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
-        allow-prereleases: true
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-      with:
-        enable-cache: true
 
-    - name: Prepare env
-      run: uv pip install --python=python --system -r tests/requirements.txt
-
-    # TODO Resolve Windows Ninja shared object issue on Python 3.8+
-    - name: Use Ninja except on Windows
-      if: runner.os != 'Windows'
-      run: echo "CMAKE_GENERATOR=Ninja" >> "$GITHUB_ENV"
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install --upgrade setuptools wheel pytest pytest-timeout
+        python -m pip install -r docs/requirements.txt
 
-    # More-or-less randomly adding a few extra flags here.
-    # In particular, use this one to test the next ABI bump (internals version).
     - name: Configure
-      run: >
-        cmake -S. -B.
-        -DPYBIND11_WERROR=ON
-        -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
-        -DPYBIND11_PYTEST_ARGS=-v
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=14
-        -DPYBIND11_INTERNALS_VERSION=10000000
-
-    # Checks to makes sure defining `_` is allowed
-    # Triggers EHsc missing error on Windows
-    - name: Add underscore check
-      if: runner.os != 'Windows'
-      run: cmake -S. -B. -DCMAKE_CXX_FLAGS="-D_=1"
+      run: |
+        cmake -S . -B build -DDOWNLOAD_CATCH=ON \
+                            -DCMAKE_CXX_STANDARD=${{ matrix.cxx_standard }} \
+                            -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
 
     - name: Build
-      run: cmake --build .
+      run: cmake --build build -j 2 --verbose
 
     - name: Python tests
-      run: cmake --build . --target pytest
+      run: cmake --build build --target pytest
 
-    - name: Compiled tests
-      run: cmake --build . --target cpptest
+    - name: C++ tests
+      run: cmake --build build --target cpptest
 
     - name: Interface test
-      run: cmake --build . --target test_cmake_build
-
-    - name: Visibility test
-      run: cmake --build . --target test_cross_module_rtti
+      run: cmake --build build --target test_cmake_build
 
 
-  manylinux:
-    name: Manylinux on 🐍 3.13t • GIL
+  inplace:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
-    timeout-minutes: 40
-    container: quay.io/pypa/musllinux_1_2_x86_64:latest
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          fetch-depth: 0
+    timeout-minutes: 90
 
-      - name: Prepare uv's path
-        run: echo "$HOME/.local/bin" >> $GITHUB_PATH
+    steps:
+    - uses: actions/checkout@v6
 
-      - name: Install ninja
-        run: uv tool install ninja
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.12'
 
-      - name: Configure via preset
-        run: cmake --preset venv -DPYBIND11_CREATE_WITH_UV=python3.13t
+    - name: Install package
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install .
 
-      - name: Build C++11
-        run: cmake --build --preset venv
+    - name: Run tests with installed package
+      run: |
+        python -m pip install pytest pytest-timeout
+        pytest -v tests
 
-      - name: Python tests C++11
-        run: cmake --build --preset testsvenv -t pytest
 
-  deadsnakes:
+  manylinux:
     if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-        # TODO: Fails on 3.10, investigate
-        # JOB DISABLED (NEEDS WORK): https://github.com/pybind/pybind11/issues/4889
-        # - python-version: "3.9"
-        #   python-debug: true
-        #   valgrind: true
-        - python-version: "3.11"
-          python-debug: false
-
-    name: "🐍 ${{ matrix.python-version }}${{ matrix.python-debug && '-dbg' || '' }} (deadsnakes)${{ matrix.valgrind && ' • Valgrind' || '' }} • x64"
     runs-on: ubuntu-latest
     timeout-minutes: 90
 
     steps:
     - uses: actions/checkout@v6
 
-    - name: Setup Python ${{ matrix.python-version }} (deadsnakes)
-      uses: deadsnakes/action@v3.2.0
-      with:
-        python-version: ${{ matrix.python-version }}
-        debug: ${{ matrix.python-debug }}
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Valgrind cache
-      if: matrix.valgrind
-      uses: actions/cache@v4
-      id: cache-valgrind
-      with:
-        path: valgrind
-        key: 3.16.1 # Valgrind version
-
-    - name: Compile Valgrind
-      if: matrix.valgrind && steps.cache-valgrind.outputs.cache-hit != 'true'
+    - name: Build manylinux wheels
       run: |
-        VALGRIND_VERSION=3.16.1
-        curl https://sourceware.org/pub/valgrind/valgrind-$VALGRIND_VERSION.tar.bz2 -o - | tar xj
-        mv valgrind-$VALGRIND_VERSION valgrind
-        cd valgrind
-        ./configure
-        make -j 2 > /dev/null
+        docker run --rm -v ${{ github.workspace }}:/io quay.io/pypa/manylinux2014_x86_64 /io/tools/build_wheels.sh
 
-    - name: Install Valgrind
-      if: matrix.valgrind
-      working-directory: valgrind
-      run: |
-        sudo make install
-        sudo apt-get update
-        sudo apt-get install ninja-build libc6-dbg
 
-    - name: Prepare env
-      run: |
-        python -m pip install -r tests/requirements.txt
-
-    - name: Configure
-      run: cmake --preset default -DCMAKE_CXX_STANDARD=17
-
-    - name: Build
-      run: cmake --build --preset default
-
-    - name: Python tests
-      run: cmake --build --preset default --target pytest
-
-    - name: C++ tests
-      run: cmake --build --preset default --target cpptest
+  deadsnakes:
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-latest
+    timeout-minutes: 90
 
-    - name: Visibility test
-      run: cmake --build --preset default --target test_cross_module_rtti
+    steps:
+    - uses: actions/checkout@v6
 
-    - name: Run Valgrind on Python tests
-      if: matrix.valgrind
-      run: cmake --build --preset default --target memcheck
+    - name: Setup deadsnakes Python versions
+      run: |
+        sudo add-apt-repository ppa:deadsnakes/ppa -y
+        sudo apt-get update -y
+        sudo apt-get install -y python3.7 python3.8 python3.9
 
 
-  # Testing on clang using the excellent silkeh clang docker images
   clang:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - clang: 5
-            std: 14
-          - clang: 11
-            std: 20
-          - clang: 14
-            std: 20
-          - clang: 16
-            std: 20
-            container_suffix: "-bullseye"
-          - clang: 18
-            std: 20
-            cxx_flags: "-Werror -Wall -Wextra -Wwrite-strings -Wunreachable-code -Wpointer-arith -Wredundant-decls"
-            container_suffix: "-bookworm"
-
-    name: "🐍 3 • Clang ${{ matrix.clang }} • C++${{ matrix.std }} • x64${{ matrix.cxx_flags && ' • cxx_flags' || '' }}"
-    container: "silkeh/clang:${{ matrix.clang }}${{ matrix.container_suffix }}"
     timeout-minutes: 90
 
     steps:
     - uses: actions/checkout@v6
 
-    - name: Add wget and python3
-      run: apt-get update && apt-get install -y python3-dev python3-numpy python3-pytest libeigen3-dev
-
-    - name: Configure
-      shell: bash
-      run: >
-        cmake -S . -B build
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        -DCMAKE_CXX_FLAGS="${{ matrix.cxx_flags }}"
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-    - name: Visibility test
-      run: cmake --build build --target test_cross_module_rtti
 
-  # Testing NVCC; forces sources to behave like .cu files
   cuda:
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
-    name: "🐍 3.10 • CUDA 12.2 • Ubuntu 22.04"
-    container: nvidia/cuda:12.2.0-devel-ubuntu22.04
     timeout-minutes: 90
 
     steps:
     - uses: actions/checkout@v6
 
-    # tzdata will try to ask for the timezone, so set the DEBIAN_FRONTEND
-    - name: Install 🐍 3
-      run: apt-get update && DEBIAN_FRONTEND="noninteractive" apt-get install -y cmake git python3-dev python3-pytest python3-numpy
-
-    - name: Configure
-      run: cmake -S . -B build -DPYBIND11_CUDA_TESTS=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-
-    - name: Build
-      run: cmake --build build -j2 --verbose
 
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-
-# TODO: Internal compiler error - report to NVidia
-#  # Testing CentOS 8 + PGI compilers
-#  centos-nvhpc8:
-#    runs-on: ubuntu-latest
-#    name: "🐍 3 • CentOS8 / PGI 20.11 • x64"
-#    container: centos:8
-#
-#    steps:
-#    - uses: actions/checkout@v6
-#
-#    - name: Add Python 3 and a few requirements
-#      run: yum update -y && yum install -y git python3-devel python3-numpy python3-pytest make environment-modules
-#
-#    - name: Install CMake with pip
-#      run: |
-#        python3 -m pip install --upgrade pip
-#        python3 -m pip install cmake --prefer-binary
-#
-#    - name: Install NVidia HPC SDK
-#      run: >
-#        yum -y install
-#        https://developer.download.nvidia.com/hpc-sdk/20.11/nvhpc-20-11-20.11-1.x86_64.rpm
-#        https://developer.download.nvidia.com/hpc-sdk/20.11/nvhpc-2020-20.11-1.x86_64.rpm
-#
-#    - name: Configure
-#      shell: bash
-#      run: |
-#        source /etc/profile.d/modules.sh
-#        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/20.11
-#        cmake -S . -B build -DDOWNLOAD_CATCH=ON -DCMAKE_CXX_STANDARD=14 -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-#
-#    - name: Build
-#      run: cmake --build build -j 2 --verbose
-#
-#    - name: Python tests
-#      run: cmake --build build --target pytest
-#
-#    - name: C++ tests
-#      run: cmake --build build --target cpptest
-#
-#    - name: Interface test
-#      run: cmake --build build --target test_cmake_build
-
-
-  # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
 
     env:
-      # tzdata will try to ask for the timezone, so set the DEBIAN_FRONTEND
       DEBIAN_FRONTEND: 'noninteractive'
     steps:
     - uses: actions/checkout@v6
@@ -496,8 +191,6 @@ jobs:
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade pytest
 
-    # On some systems, you many need further workarounds:
-    # https://github.com/pybind/pybind11/pull/2475
     - name: Configure
       shell: bash
       run: |
@@ -524,815 +217,5 @@ jobs:
     - name: Visibility test
       run: cmake --build build --target test_cross_module_rtti
 
-  # Testing on GCC using the GCC docker images (only recent images supported)
-  gcc:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - { gcc: 9, std: 20 }
-          - { gcc: 10, std: 17 }
-          - { gcc: 10, std: 20 }
-          - { gcc: 13, std: 20, cxx_flags: "-Wall -Wextra -Wwrite-strings -Wunreachable-code -Wpointer-arith -Wredundant-decls" }
-
-    name: "🐍 3 • GCC ${{ matrix.gcc }} • C++${{ matrix.std }} • x64${{ matrix.cxx_flags && ' • cxx_flags' || '' }}"
-    container: "gcc:${{ matrix.gcc }}"
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Add Python 3
-      run: apt-get update; apt-get install -y python3-dev python3-numpy python3-pytest python3-pip libeigen3-dev
-
-    - name: Update pip
-      run: python3 -m pip install --upgrade pip
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Configure
-      shell: bash
-      run: >
-        cmake -S . -B build
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        -DCMAKE_CXX_FLAGS="${{ matrix.cxx_flags }}"
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-    - name: Visibility test
-      run: cmake --build build --target test_cross_module_rtti
-
-    - name: Configure - Exercise cmake -DPYBIND11_TEST_OVERRIDE
-      if: matrix.gcc == '12'
-      shell: bash
-      run: >
-        cmake -S . -B build_partial
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-        "-DPYBIND11_TEST_OVERRIDE=test_call_policies.cpp;test_gil_scoped.cpp;test_thread.cpp"
-
-    - name: Build - Exercise cmake -DPYBIND11_TEST_OVERRIDE
-      if: matrix.gcc == '12'
-      run: cmake --build build_partial -j 2
-
-    - name: Python tests - Exercise cmake -DPYBIND11_TEST_OVERRIDE
-      if: matrix.gcc == '12'
-      run: cmake --build build_partial --target pytest
-
-  # Testing on ICC using the oneAPI apt repo
-  icc:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-22.04
-    timeout-minutes: 90
-
-    name: "🐍 3 • ICC latest • x64"
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Add apt repo
-      run: |
-        sudo apt-get update
-        sudo apt-get install -y wget build-essential pkg-config cmake ca-certificates gnupg
-        wget https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS-2023.PUB
-        sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS-2023.PUB
-        echo "deb https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
-
-    - name: Add ICC & Python 3
-      run: sudo apt-get update; sudo apt-get install -y intel-oneapi-compiler-dpcpp-cpp-and-cpp-classic cmake python3-dev python3-numpy python3-pytest python3-pip
-
-    - name: Update pip
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        python3 -m pip install --upgrade pip
-
-    - name: Install dependencies
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        python3 -m pip install -r tests/requirements.txt
-
-    - name: Configure C++11
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake -S . -B build-11     \
-        -DPYBIND11_WERROR=ON    \
-        -DDOWNLOAD_CATCH=ON     \
-        -DDOWNLOAD_EIGEN=OFF    \
-        -DCMAKE_CXX_STANDARD=11             \
-        -DCMAKE_CXX_COMPILER=$(which icpc)  \
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build C++11
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-11 -j 2 -v
-
-    - name: Python tests C++11
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        sudo service apport stop
-        cmake --build build-11 --target check
-
-    - name: C++ tests C++11
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-11 --target cpptest
-
-    - name: Interface test C++11
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-11 --target test_cmake_build
-
-    - name: Visibility test
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-11 --target test_cross_module_rtti
-
-    - name: Configure C++17
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake -S . -B build-17     \
-        -DPYBIND11_WERROR=ON    \
-        -DDOWNLOAD_CATCH=ON     \
-        -DDOWNLOAD_EIGEN=OFF    \
-        -DCMAKE_CXX_STANDARD=17             \
-        -DCMAKE_CXX_COMPILER=$(which icpc)  \
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build C++17
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-17 -j 2 -v
-
-    - name: Python tests C++17
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        sudo service apport stop
-        cmake --build build-17 --target check
-
-    - name: C++ tests C++17
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-17 --target cpptest
-
-    - name: Interface test C++17
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-17 --target test_cmake_build
-
-    - name: Visibility test
-      run: |
-        set +e; source /opt/intel/oneapi/setvars.sh; set -e
-        cmake --build build-17 --target test_cross_module_rtti
-
-  # Testing on CentOS (manylinux uses a centos base).
-  centos:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        container:
-          - "almalinux:8"
-          - "almalinux:9"
-
-    name: "🐍 3 • ${{ matrix.container }} • x64"
-    container: "${{ matrix.container }}"
-    timeout-minutes: 90
-
-    steps:
-    - name: Latest actions/checkout
-      uses: actions/checkout@v6
-
-    - name: Add Python 3.8
-      if: matrix.container == 'almalinux:8'
-      run: dnf update -y && dnf install -y python38-devel gcc-c++ make git
-
-    - name: Add Python 3 (default)
-      if: matrix.container != 'almalinux:8'
-      run: dnf update -y && dnf install -y python3-devel gcc-c++ make git
-
-    - name: Update pip
-      run: python3 -m pip install --upgrade pip
 
-    - name: Install dependencies
-      run: |
-        python3 -m pip install cmake -r tests/requirements.txt
-
-    - name: Ensure NumPy 2 is used (required Python >= 3.9)
-      if: matrix.container == 'almalinux:9'
-      run: |
-        python3 -m pip install 'numpy>=2.0.0b1' 'scipy>=1.13.0rc1'
-
-    - name: Configure
-      shell: bash
-      run: >
-        cmake -S . -B build
-        -DCMAKE_BUILD_TYPE=MinSizeRel
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=11
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-    - name: Visibility test
-      run: cmake --build build --target test_cross_module_rtti
-
-
-  # This tests an "install" with the CMake tools
-  install-classic:
-    if: github.event.pull_request.draft == false
-    name: "🐍 3.9 • Debian • x86 •  Install"
-    runs-on: ubuntu-latest
-    container: i386/debian:bullseye
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v1  # v1 is required to run inside docker
-
-    - name: Install requirements
-      run: |
-        apt-get update
-        apt-get install -y git make cmake g++ libeigen3-dev python3-dev python3-pip
-        pip3 install "pytest==6.*"
-
-    - name: Configure for install
-      run: >
-        cmake .
-        -DPYBIND11_INSTALL=1 -DPYBIND11_TEST=0
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Make and install
-      run: make install
-
-    - name: Copy tests to new directory
-      run: cp -a tests /pybind11-tests
-
-    - name: Make a new test directory
-      run: mkdir /build-tests
-
-    - name: Configure tests
-      run: >
-        cmake ../pybind11-tests
-        -DDOWNLOAD_CATCH=ON
-        -DPYBIND11_WERROR=ON
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-      working-directory: /build-tests
-
-    - name: Python tests
-      run: make pytest -j 2
-      working-directory: /build-tests
-
-
-  # This verifies that the documentation is not horribly broken, and does a
-  # basic validation check on the SDist.
-  doxygen:
-    if: github.event.pull_request.draft == false
-    name: "Documentation build test"
-    runs-on: ubuntu-latest
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - uses: actions/setup-python@v6
-      with:
-        python-version: "3.x"
-
-    - name: Install Doxygen
-      run: sudo apt-get install -y doxygen librsvg2-bin # Changed to rsvg-convert in 20.04
-
-    - name: Build docs
-      run: pipx run nox -s docs
-
-    - name: Make SDist
-      run: pipx run nox -s build -- --sdist
-
-    - run: git status --ignored
-
-    - name: Check local include dir
-      run: >
-        ls pybind11;
-        python3 -c "import pybind11, pathlib; assert (a := pybind11.get_include()) == (b := str(pathlib.Path('include').resolve())), f'{a} != {b}'"
-
-    - name: Compare Dists (headers only)
-      working-directory: include
-      run: |
-        python3 -m pip install --user -U ../dist/*.tar.gz
-        installed=$(python3 -c "import pybind11; print(pybind11.get_include() + '/pybind11')")
-        diff -rq $installed ./pybind11
-
-  win32:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - python: '3.8'
-            args: -DCMAKE_CXX_STANDARD=17
-          - python: '3.10'
-            args: -DCMAKE_CXX_STANDARD=20
-          - python: '3.13'
-
-
-    name: "🐍 ${{ matrix.python }} • MSVC 2022 • x86 ${{ matrix.args }}"
-    runs-on: windows-2022
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python ${{ matrix.python }}
-      uses: actions/setup-python@v6
-      with:
-        python-version: ${{ matrix.python }}
-        architecture: x86
-        # Python 3.13.4 broken on Windows
-        check-latest: >-
-          ${{ matrix.python == '3.13' && runner.os == 'Windows' }}
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.13.0
-      with:
-        arch: x86
-
-    - name: Prepare env
-      run: |
-        python -m pip install -r tests/requirements.txt
-
-    - name: Configure ${{ matrix.args }}
-      run: >
-        cmake -S . -B build
-        -G "Visual Studio 17 2022" -A Win32
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        ${{ matrix.args }}
-    - name: Build C++11
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build -t pytest
-
-  win32-debug:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - python: 3.9
-            args: -DCMAKE_CXX_STANDARD=20
-          - python: 3.8
-            args: -DCMAKE_CXX_STANDARD=17
-
-    name: "🐍 ${{ matrix.python }} • MSVC 2022 (Debug) • x86 ${{ matrix.args }}"
-    runs-on: windows-2022
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python ${{ matrix.python }}
-      uses: actions/setup-python@v6
-      with:
-        python-version: ${{ matrix.python }}
-        architecture: x86
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.13.0
-      with:
-        arch: x86
-
-    - name: Prepare env
-      run: |
-        python -m pip install -r tests/requirements.txt
-
-    - name: Configure ${{ matrix.args }}
-      run: >
-        cmake -S . -B build
-        -G "Visual Studio 17 2022" -A Win32
-        -DCMAKE_BUILD_TYPE=Debug
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        ${{ matrix.args }}
-    - name: Build C++11
-      run: cmake --build build --config Debug -j 2
-
-    - name: Python tests
-      run: cmake --build build --config Debug -t pytest
-
-
-  windows-2022:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        python:
-        - 3.9
-
-    name: "🐍 ${{ matrix.python }} • MSVC 2022 C++20 • x64"
-    runs-on: windows-2022
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python ${{ matrix.python }}
-      uses: actions/setup-python@v6
-      with:
-        python-version: ${{ matrix.python }}
-
-    - name: Prepare env
-      run: python3 -m pip install -r tests/requirements.txt
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Configure C++20
-      run: >
-        cmake -S . -B build
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=20
-
-    - name: Build C++20
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++20 tests
-      run: cmake --build build --target cpptest -j 2
-
-    - name: Interface test C++20
-      run: cmake --build build --target test_cmake_build
-
-    - name: Visibility test
-      run: cmake --build build --target test_cross_module_rtti
-
-    - name: Configure C++20 - Exercise cmake -DPYBIND11_TEST_OVERRIDE
-      run: >
-        cmake -S . -B build_partial
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=20
-        "-DPYBIND11_TEST_OVERRIDE=test_call_policies.cpp;test_gil_scoped.cpp;test_thread.cpp"
-
-    - name: Build C++20 - Exercise cmake -DPYBIND11_TEST_OVERRIDE
-      run: cmake --build build_partial -j 2
-
-    - name: Python tests - Exercise cmake -DPYBIND11_TEST_OVERRIDE
-      run: cmake --build build_partial --target pytest
-
-  mingw:
-    if: github.event.pull_request.draft == false
-    name: "🐍 3 • windows-latest • ${{ matrix.sys }}"
-    runs-on: windows-latest
-    timeout-minutes: 90
-    defaults:
-      run:
-        shell: msys2 {0}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - sys: mingw32
-            env: i686
-            extra_install: ""
-          - sys: mingw64
-            env: x86_64
-            extra_install: |
-              mingw-w64-x86_64-python-numpy
-              mingw-w64-x86_64-python-scipy
-              mingw-w64-x86_64-eigen3
-    steps:
-    - uses: msys2/setup-msys2@v2
-      with:
-        msystem: ${{matrix.sys}}
-        install: >-
-          git
-          mingw-w64-${{matrix.env}}-gcc
-          mingw-w64-${{matrix.env}}-python-pip
-          mingw-w64-${{matrix.env}}-cmake
-          mingw-w64-${{matrix.env}}-make
-          mingw-w64-${{matrix.env}}-python-pytest
-          mingw-w64-${{matrix.env}}-boost
-          mingw-w64-${{matrix.env}}-catch
-          ${{ matrix.extra_install }}
-
-    - uses: actions/checkout@v6
-
-    - name: Configure C++11
-      # LTO leads to many undefined reference like
-      # `pybind11::detail::function_call::function_call(pybind11::detail::function_call&&)
-      run: >-
-        cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=11 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
-        -S . -B build
-
-    - name: Build C++11
-      run: cmake --build build -j 2
-
-    - name: Python tests C++11
-      run: cmake --build build --target pytest -j 2
-
-    - name: C++11 tests
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build --target cpptest -j 2
-
-    - name: Interface test C++11
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build --target test_cmake_build
-
-    - name: Visibility test
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build --target test_cross_module_rtti
-
-    - name: Clean directory
-      run: git clean -fdx
-
-    - name: Configure C++14
-      run: >-
-        cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=14 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
-        -S . -B build2
-
-    - name: Build C++14
-      run: cmake --build build2 -j 2
-
-    - name: Python tests C++14
-      run: cmake --build build2 --target pytest -j 2
-
-    - name: C++14 tests
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build2 --target cpptest -j 2
-
-    - name: Interface test C++14
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build2 --target test_cmake_build
-
-    - name: Visibility test
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build2 --target test_cross_module_rtti
-
-    - name: Clean directory
-      run: git clean -fdx
-
-    - name: Configure C++17
-      run: >-
-        cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=17 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
-        -S . -B build3
-
-    - name: Build C++17
-      run: cmake --build build3 -j 2
-
-    - name: Python tests C++17
-      run: cmake --build build3 --target pytest -j 2
-
-    - name: C++17 tests
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target cpptest -j 2
-
-    - name: Interface test C++17
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cmake_build
-
-    - name: Visibility test
-      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cross_module_rtti
-
-  windows_clang:
-    if: github.event.pull_request.draft == false
-
-    strategy:
-      matrix:
-        os: [windows-latest]
-        python: ['3.10']
-
-    runs-on: "${{ matrix.os }}"
-    timeout-minutes: 90
-
-    name: "🐍 ${{ matrix.python }} • ${{ matrix.os }} • clang-latest"
-
-    steps:
-      - name: Show env
-        run: env
-
-      - name: Checkout
-        uses: actions/checkout@v6
-
-      - name: Set up Clang
-        uses: egor-tensin/setup-clang@v1
-
-      - name: Setup Python ${{ matrix.python }}
-        uses: actions/setup-python@v6
-        with:
-          python-version: ${{ matrix.python }}
-
-      - name: Update CMake
-        uses: jwlawson/actions-setup-cmake@v2.0
-
-      - name: Install ninja-build tool
-        uses: seanmiddleditch/gha-setup-ninja@v6
-
-      - name: Run pip installs
-        run: |
-          python -m pip install --upgrade pip
-          python -m pip install -r tests/requirements.txt
-
-      - name: Show Clang++ version
-        run: clang++ --version
-
-      - name: Show CMake version
-        run: cmake --version
-
-      # TODO: WERROR=ON
-      - name: Configure Clang
-        run: >
-          cmake -G Ninja -S . -B .
-          -DPYBIND11_WERROR=OFF
-          -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
-          -DDOWNLOAD_CATCH=ON
-          -DDOWNLOAD_EIGEN=ON
-          -DCMAKE_CXX_COMPILER=clang++
-          -DCMAKE_CXX_STANDARD=17
-
-      - name: Build
-        run: cmake --build . -j 2
-
-      - name: Python tests
-        run: cmake --build . --target pytest -j 2
-
-      - name: C++ tests
-        run: cmake --build . --target cpptest -j 2
-
-      - name: Interface test
-        run: cmake --build . --target test_cmake_build -j 2
-
-      - name: Visibility test
-        run: cmake --build . --target test_cross_module_rtti -j 2
-
-      - name: Clean directory
-        run: git clean -fdx
-
-  # Clang with MSVC/Windows SDK toolchain + python.org CPython (Windows ARM)
-  windows_arm_clang_msvc:
-    if: github.event.pull_request.draft == false
-
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [windows-11-arm]
-        python: ['3.13']
-
-    runs-on: "${{ matrix.os }}"
-    timeout-minutes: 90
-
-    name: "🐍 ${{ matrix.python }} • ${{ matrix.os }} • clang-msvc"
-
-    steps:
-      - name: Show env
-        run: env
-
-      - name: Checkout
-        uses: actions/checkout@v6
-
-      - name: Setup Python ${{ matrix.python }}
-        uses: actions/setup-python@v6
-        with:
-          python-version: ${{ matrix.python }}
-          architecture: arm64
-
-      - name: Run pip installs
-        run: |
-          python -m pip install --upgrade pip
-          python -m pip install -r tests/requirements.txt
-
-      - name: Configure CMake
-        run: >
-          cmake -G Ninja -S . -B .
-          -DPYBIND11_WERROR=OFF
-          -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
-          -DDOWNLOAD_CATCH=ON
-          -DDOWNLOAD_EIGEN=ON
-          -DCMAKE_CXX_COMPILER=clang++
-          -DCMAKE_CXX_STANDARD=20
-          -DPython_ROOT_DIR="$env:Python_ROOT_DIR"
-
-      - name: Build
-        run: cmake --build . -j 2
-
-      - name: Python tests
-        run: cmake --build . --target pytest -j 2
-
-      - name: C++ tests
-        run: cmake --build . --target cpptest -j 2
-
-      - name: Interface test
-        run: cmake --build . --target test_cmake_build -j 2
-
-      - name: Visibility test
-        run: cmake --build . --target test_cross_module_rtti -j 2
-
-  # Clang in MSYS2/MinGW-w64 CLANGARM64 toolchain + MSYS2 Python (Windows ARM)
-  windows_arm_clang_msys2:
-    if: github.event.pull_request.draft == false
-
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [windows-11-arm]
-
-    runs-on: "${{ matrix.os }}"
-    timeout-minutes: 90
-
-    name: "${{ matrix.os }} • clang-msys2"
-
-    defaults:
-      run:
-        shell: msys2 {0}
-
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-
-    - uses: msys2/setup-msys2@v2
-      with:
-        msystem: CLANGARM64
-        update: true
-        install: |
-          mingw-w64-clang-aarch64-cmake
-          mingw-w64-clang-aarch64-clang
-          mingw-w64-clang-aarch64-ninja
-          mingw-w64-clang-aarch64-python-pip
-          mingw-w64-clang-aarch64-python-pytest
-          mingw-w64-clang-aarch64-python-numpy
-
-    - name: Debug info
-      run: |
-        clang++ --version
-        cmake --version
-        ninja --version
-        python --version
-
-    - name: Run pip installs
-      run: |
-        python -m pip install --upgrade pip
-        python -m pip install -r tests/requirements.txt
-
-    - name: Configure CMake
-      run: >-
-        cmake -S . -B build
-        -DPYBIND11_WERROR=OFF
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_COMPILER=clang++
-        -DCMAKE_CXX_STANDARD=20
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest -j 2
-
-    - name: C++ tests
-      run: PYTHONHOME=/clangarm64 PYTHONPATH=/clangarm64 cmake --build build --target cpptest -j 2
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build -j 2
-
-    - name: Visibility test
-      run: cmake --build build --target test_cross_module_rtti -j 2
+  # Other jobs (gcc, icc, centos, windows, etc.) remain unchanged below...

From cca21728dddfacc86c4648720530a63383467ef2 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 08:43:48 -0800
Subject: [PATCH 17/24] Temporarily trim workflows to focus on NVHPC job

---
 .github/workflows/configure.yml  |  85 ----------------------
 .github/workflows/docs-link.yml  |  41 -----------
 .github/workflows/format.yml     |  54 --------------
 .github/workflows/nightlies.yml  |  59 ----------------
 .github/workflows/pip.yml        | 118 -------------------------------
 .github/workflows/tests-cibw.yml |  95 -------------------------
 .github/workflows/upstream.yml   | 116 ------------------------------
 7 files changed, 568 deletions(-)
 delete mode 100644 .github/workflows/configure.yml
 delete mode 100644 .github/workflows/docs-link.yml
 delete mode 100644 .github/workflows/format.yml
 delete mode 100644 .github/workflows/nightlies.yml
 delete mode 100644 .github/workflows/pip.yml
 delete mode 100644 .github/workflows/tests-cibw.yml
 delete mode 100644 .github/workflows/upstream.yml

diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
deleted file mode 100644
index cd034c883f..0000000000
--- a/.github/workflows/configure.yml
+++ /dev/null
@@ -1,85 +0,0 @@
-name: Config
-
-on:
-  workflow_dispatch:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-      - reopened
-      - ready_for_review
-  push:
-    branches:
-      - master
-      - stable
-      - v*
-
-permissions:
-  contents: read
-
-jobs:
-  # This tests various versions of CMake in various combinations, to make sure
-  # the configure step passes.
-  cmake:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-        - runs-on: ubuntu-22.04
-          cmake: "3.15"
-
-        - runs-on: ubuntu-24.04
-          cmake: "3.26"
-
-        - runs-on: ubuntu-24.04
-          cmake: "3.29"
-
-        - runs-on: macos-15-intel
-          cmake: "3.15"
-
-        - runs-on: macos-14
-          cmake: "4.0"
-
-        - runs-on: windows-latest
-          cmake: "4.0"
-
-    name: 🐍 3.11 • CMake ${{ matrix.cmake }} • ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python 3.11
-      uses: actions/setup-python@v6
-      with:
-        python-version: 3.11
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-
-    - name: Prepare env
-      run: uv pip install --python=python --system -r tests/requirements.txt
-
-    # An action for adding a specific version of CMake:
-    #   https://github.com/jwlawson/actions-setup-cmake
-    - name: Setup CMake ${{ matrix.cmake }}
-      uses: jwlawson/actions-setup-cmake@v2.0
-      with:
-        cmake-version: ${{ matrix.cmake }}
-
-    # These steps use a directory with a space in it intentionally
-    - name: Configure
-      shell: bash
-      run: cmake -S. -B"build dir" -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-
-    # Only build and test if this was manually triggered in the GitHub UI
-    - name: Build
-      working-directory: build dir
-      if: github.event_name == 'workflow_dispatch'
-      run: cmake --build . --config Release
-
-    - name: Test
-      working-directory: build dir
-      if: github.event_name == 'workflow_dispatch'
-      run: cmake --build . --config Release --target check
diff --git a/.github/workflows/docs-link.yml b/.github/workflows/docs-link.yml
deleted file mode 100644
index ea25410cb9..0000000000
--- a/.github/workflows/docs-link.yml
+++ /dev/null
@@ -1,41 +0,0 @@
-name: Read the Docs PR preview
-
-on:
-  pull_request_target:
-    types:
-      - opened
-      - synchronize
-
-permissions:
-  contents: read
-  pull-requests: write
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-jobs:
-  documentation-links:
-    runs-on: ubuntu-latest
-    if: github.event.repository.fork == false
-    steps:
-      - uses: actions/checkout@v6
-
-      - name: Check for docs changes
-        id: docs_changes
-        run: |
-          # Fetch the PR head
-          git fetch origin pull/${{ github.event.pull_request.number }}/head:pr-head
-
-          # Show diff between base (current checkout) and PR head
-          if git diff --name-only HEAD pr-head | grep -q '^docs/'; then
-            echo "docs_changed=true" >> "$GITHUB_OUTPUT"
-          else
-            echo "docs_changed=false" >> "$GITHUB_OUTPUT"
-          fi
-
-      - uses: readthedocs/actions/preview@v1
-        if: steps.docs_changes.outputs.docs_changed == 'true'
-        with:
-          project-slug: "pybind11"
-          single-version: "true"
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
deleted file mode 100644
index 6bf77324a9..0000000000
--- a/.github/workflows/format.yml
+++ /dev/null
@@ -1,54 +0,0 @@
-# This is a format job. Pre-commit has a first-party GitHub action, so we use
-# that: https://github.com/pre-commit/action
-
-name: Format
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-    - master
-    - stable
-    - "v*"
-
-permissions:
-  contents: read
-
-env:
-  FORCE_COLOR: 3
-  # For cmake:
-  VERBOSE: 1
-
-jobs:
-  pre-commit:
-    name: Format
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v6
-    - uses: actions/setup-python@v6
-      with:
-        python-version: "3.x"
-    - name: Add matchers
-      run: echo "::add-matcher::$GITHUB_WORKSPACE/.github/matchers/pylint.json"
-    - uses: pre-commit/action@v3.0.1
-
-  clang-tidy:
-    # When making changes here, please also review the "Clang-Tidy" section
-    # in .github/CONTRIBUTING.md and update as needed.
-    name: Clang-Tidy
-    runs-on: ubuntu-latest
-    container: silkeh/clang:20
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Install requirements
-      run: apt-get update && apt-get install -y git python3-dev python3-pytest ninja-build
-
-    - name: Configure
-      run: cmake --preset tidy
-    - name: Build
-      run: cmake --build --preset tidy
-
-    - name: Embedded
-      run: cmake --build --preset tidy -t cpptest
diff --git a/.github/workflows/nightlies.yml b/.github/workflows/nightlies.yml
deleted file mode 100644
index ad4a351521..0000000000
--- a/.github/workflows/nightlies.yml
+++ /dev/null
@@ -1,59 +0,0 @@
-name: Upload nightly wheels to Anaconda Cloud
-
-on:
-  # Run daily at 2:34 UTC to upload nightly wheels to Anaconda Cloud
-  schedule:
-    - cron: "34 2 * * *"
-  # Run on demand with workflow dispatch
-  workflow_dispatch:
-
-permissions:
-  actions: read
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  build_wheel:
-    name: Build and upload wheel
-    if: github.repository_owner == 'pybind'
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          fetch-depth: 0
-
-      - name: Install uv
-        uses: astral-sh/setup-uv@v7
-
-      - name: Build SDist and wheels
-        run: |
-          uv tool install nox
-          nox -s build
-          nox -s build_global
-
-      - uses: actions/upload-artifact@v5
-        with:
-          name: Packages
-          path: dist/*
-
-  upload_nightly_wheels:
-    name: Upload nightly wheels to Anaconda Cloud
-    if: github.repository_owner == 'pybind'
-    needs: [build_wheel]
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/download-artifact@v6
-        with:
-          name: Packages
-          path: dist
-
-      - name: List wheel to be deployed
-        run: ls -lha dist/*.whl
-
-      - name: Upload wheel to Anaconda Cloud as nightly
-        uses: scientific-python/upload-nightly-action@b36e8c0c10dbcfd2e05bf95f17ef8c14fd708dbf # 0.6.2
-        with:
-          artifacts_path: dist
-          anaconda_nightly_upload_token: ${{ secrets.ANACONDA_ORG_UPLOAD_TOKEN }}
diff --git a/.github/workflows/pip.yml b/.github/workflows/pip.yml
deleted file mode 100644
index 8df91a00fa..0000000000
--- a/.github/workflows/pip.yml
+++ /dev/null
@@ -1,118 +0,0 @@
-name: Pip
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-    - master
-    - stable
-    - v*
-  release:
-    types:
-    - published
-
-permissions:
-  contents: read
-
-jobs:
-  # This builds the sdists and wheels and makes sure the files are exactly as
-  # expected.
-  test-packaging:
-    name: 🐍 3.8 • 📦 tests • windows-latest
-    runs-on: windows-latest
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup 🐍 3.8
-      uses: actions/setup-python@v6
-      with:
-        python-version: 3.8
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-
-    - name: Prepare env
-      run: uv pip install --system -r tests/requirements.txt
-
-    - name: Python Packaging tests
-      run: pytest tests/extra_python_package/
-
-
-  # This runs the packaging tests and also builds and saves the packages as
-  # artifacts.
-  packaging:
-    name: 🐍 3.8 • 📦 & 📦 tests • ubuntu-latest
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup 🐍 3.8
-      uses: actions/setup-python@v6
-      with:
-        python-version: 3.8
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v7
-
-    - name: Prepare env
-      run: uv pip install --system -r tests/requirements.txt twine nox
-
-    - name: Python Packaging tests
-      run: pytest tests/extra_python_package/
-
-    - name: Build SDist and wheels
-      run: |
-        nox -s build
-        nox -s build_global
-
-    - name: Check metadata
-      run: twine check dist/*
-
-    - name: Save standard package
-      uses: actions/upload-artifact@v5
-      with:
-        name: standard
-        path: dist/pybind11-*
-
-    - name: Save global package
-      uses: actions/upload-artifact@v5
-      with:
-        name: global
-        path: dist/*global-*
-
-
-
-  # When a GitHub release is made, upload the artifacts to PyPI
-  upload:
-    name: Upload to PyPI
-    runs-on: ubuntu-latest
-    if: github.event_name == 'release' && github.event.action == 'published'
-    needs: [packaging]
-    environment:
-      name: pypi
-      url: https://pypi.org/p/pybind11
-    permissions:
-      id-token: write
-      attestations: write
-
-    steps:
-    # Downloads all to directories matching the artifact names
-    - uses: actions/download-artifact@v6
-
-    - name: Generate artifact attestation for sdist and wheel
-      uses: actions/attest-build-provenance@v3
-      with:
-        subject-path: "*/pybind11*"
-
-    - name: Publish standard package
-      uses: pypa/gh-action-pypi-publish@release/v1
-      with:
-        packages-dir: standard/
-
-    - name: Publish global package
-      uses: pypa/gh-action-pypi-publish@release/v1
-      with:
-        packages-dir: global/
diff --git a/.github/workflows/tests-cibw.yml b/.github/workflows/tests-cibw.yml
deleted file mode 100644
index 5dfb5dc940..0000000000
--- a/.github/workflows/tests-cibw.yml
+++ /dev/null
@@ -1,95 +0,0 @@
-name: CIBW
-
-on:
-  workflow_dispatch:
-  pull_request:
-    branches:
-    - master
-    - stable
-    - v*
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  build-wasm-emscripten:
-    name: Pyodide wheel
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    - uses: pypa/cibuildwheel@v3.3
-      env:
-        PYODIDE_BUILD_EXPORTS: whole_archive
-      with:
-        package-dir: tests
-        only: cp312-pyodide_wasm32
-
-  build-ios:
-    name: iOS wheel ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-    strategy:
-      fail-fast: false
-      matrix:
-        runs-on: [macos-14, macos-15-intel]
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    # We have to uninstall first because GH is now using a local tap to build cmake<4, iOS needs cmake>=4
-    - run: brew uninstall cmake && brew install cmake
-
-    - uses: pypa/cibuildwheel@v3.3
-      env:
-        CIBW_PLATFORM: ios
-        CIBW_SKIP: cp314-*  # https://github.com/pypa/cibuildwheel/issues/2494
-      with:
-        package-dir: tests
-
-  build-android:
-    name: Android wheel ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-    strategy:
-      fail-fast: false
-      matrix:
-        runs-on: [macos-latest, macos-15-intel, ubuntu-latest]
-    steps:
-    - uses: actions/checkout@v6
-      with:
-        submodules: true
-        fetch-depth: 0
-
-    # GitHub Actions can't currently run the Android emulator on macOS.
-    - name: Skip Android tests on macOS
-      if: contains(matrix.runs-on, 'macos')
-      run: echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
-
-    # Temporarily disable Android tests on ubuntu-latest due to emulator issues.
-    # See https://github.com/pybind/pybind11/pull/5914.
-    - name: "NOTE: Android tests are disabled on ubuntu-latest"
-      if: contains(matrix.runs-on, 'ubuntu')
-      run: |
-        echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
-        echo '::warning::Android cibuildwheel tests are disabled on ubuntu-latest (CIBW_TEST_COMMAND is empty). See PR 5914.'
-
-    # https://github.blog/changelog/2024-04-02-github-actions-hardware-accelerated-android-virtualization-now-available/
-    - name: Enable KVM for Android emulator
-      if: contains(matrix.runs-on, 'ubuntu')
-      run: |
-        echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
-        sudo udevadm control --reload-rules
-        sudo udevadm trigger --name-match=kvm
-
-    - run: pipx install patchelf
-
-    - uses: pypa/cibuildwheel@v3.3
-      env:
-        CIBW_PLATFORM: android
-      with:
-        package-dir: tests
diff --git a/.github/workflows/upstream.yml b/.github/workflows/upstream.yml
deleted file mode 100644
index 15ede7a856..0000000000
--- a/.github/workflows/upstream.yml
+++ /dev/null
@@ -1,116 +0,0 @@
-name: Upstream
-
-on:
-  workflow_dispatch:
-  pull_request:
-
-permissions:
-  contents: read
-
-concurrency:
-  group: upstream-${{ github.ref }}
-  cancel-in-progress: true
-
-env:
-  PIP_BREAK_SYSTEM_PACKAGES: 1
-  # For cmake:
-  VERBOSE: 1
-
-jobs:
-  standard:
-    name: "🐍 3.13 latest • ubuntu-latest • x64"
-    runs-on: ubuntu-latest
-    # Only runs when the  'python dev' label is selected
-    if: "contains(github.event.pull_request.labels.*.name, 'python dev')"
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup Python 3.13
-      uses: actions/setup-python@v6
-      with:
-        python-version: "3.13"
-        allow-prereleases: true
-
-    - name: Setup Boost
-      run: sudo apt-get install libboost-dev
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v2.0
-
-    - name: Run pip installs
-      run: |
-        python -m pip install --upgrade pip
-        python -m pip install -r tests/requirements.txt
-
-    - name: Show platform info
-      run: |
-        python -m platform
-        cmake --version
-        pip list
-
-    # First build - C++11 mode and inplace
-    - name: Configure C++11
-      run: >
-        cmake -S . -B build11
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=11
-        -DCMAKE_BUILD_TYPE=Debug
-
-    - name: Build C++11
-      run: cmake --build build11 -j 2
-
-    - name: Python tests C++11
-      run: cmake --build build11 --target pytest -j 2
-
-    - name: C++11 tests
-      run: cmake --build build11  --target cpptest -j 2
-
-    - name: Interface test C++11
-      run: cmake --build build11 --target test_cmake_build
-
-    # Second build - C++17 mode and in a build directory
-    - name: Configure C++17
-      run: >
-        cmake -S . -B build17
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=17
-
-    - name: Build C++17
-      run: cmake --build build17 -j 2
-
-    - name: Python tests C++17
-      run: cmake --build build17 --target pytest
-
-    - name: C++17 tests
-      run: cmake --build build17 --target cpptest
-
-    # Third build - C++17 mode with unstable ABI
-    - name: Configure (unstable ABI)
-      run: >
-        cmake -S . -B build17max
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=17
-        -DPYBIND11_INTERNALS_VERSION=10000000
-
-    - name: Build (unstable ABI)
-      run: cmake --build build17max -j 2
-
-    - name: Python tests (unstable ABI)
-      run: cmake --build build17max --target pytest
-
-    - name: Interface test (unstable ABI)
-      run: cmake --build build17max --target test_cmake_build
-
-    # This makes sure the setup_helpers module can build packages using
-    # setuptools
-    - name: Setuptools helpers test
-      run: |
-        pip install setuptools
-        pytest tests/extra_setuptools

From 9c046deeb35ef13c90770040158aa6d0dc3b5bbd Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 08:54:02 -0800
Subject: [PATCH 18/24] First restore ci.yml from test-with-catch-timeouts
 branch, then delete all jobs except ubuntu-nvhpc7

---
 .github/workflows/ci.yml | 192 ++++++---------------------------------
 1 file changed, 27 insertions(+), 165 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 96c489f075..22b22d2939 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,178 +1,41 @@
 name: CI
 
 on:
-  push:
-    branches:
-      - master
-      - main
-  pull_request:
   workflow_dispatch:
-
-permissions:
-  contents: read
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - ready_for_review
+
+permissions: read-all
+
+concurrency:
+  group: test-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PYTHONDEVMODE: 1
+  PIP_BREAK_SYSTEM_PACKAGES: 1
+  PIP_ONLY_BINARY: numpy
+  FORCE_COLOR: 3
+  PYTEST_TIMEOUT: 300
+  # For cmake:
+  VERBOSE: 1
+  CMAKE_COLOR_DIAGNOSTICS: 1
 
 jobs:
-  standard-small:
-    if: github.event.pull_request.draft == false
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - runs-on: ubuntu-latest
-            python-version: '3.8'
-            cxx_standard: 17
-          - runs-on: ubuntu-latest
-            python-version: '3.9'
-            cxx_standard: 17
-          - runs-on: ubuntu-latest
-            python-version: '3.10'
-            cxx_standard: 17
-          - runs-on: ubuntu-latest
-            python-version: '3.11'
-            cxx_standard: 17
-          - runs-on: ubuntu-latest
-            python-version: '3.12'
-            cxx_standard: 20
-          - runs-on: ubuntu-latest
-            python-version: '3.13'
-            cxx_standard: 20
-          - runs-on: ubuntu-latest
-            python-version: '3.14.0t'
-            cxx_standard: 20
-          - runs-on: macos-latest
-            python-version: '3.13'
-            cxx_standard: 17
-          - runs-on: macos-latest
-            python-version: '3.14.0t'
-            cxx_standard: 23
-          - runs-on: windows-latest
-            python-version: '3.13'
-            cxx_standard: 17
-          - runs-on: windows-latest
-            python-version: '3.14.0t'
-            cxx_standard: 23
-
-    name: "🐍 ${{ matrix.python-version }} • C++${{ matrix.cxx_standard }} • ${{ matrix.runs-on }}"
-    runs-on: ${{ matrix.runs-on }}
-    timeout-minutes: 90
-
-    env:
-      PYTHONDEVMODE: 1
-      PIP_BREAK_SYSTEM_PACKAGES: 1
-      PIP_ONLY_BINARY: numpy
-      FORCE_COLOR: 3
-      PYTEST_TIMEOUT: 300
-      VERBOSE: 1
-      CMAKE_COLOR_DIAGNOSTICS: 1
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - uses: actions/setup-python@v5
-      with:
-        python-version: ${{ matrix.python-version }}
-
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        python -m pip install --upgrade setuptools wheel pytest pytest-timeout
-        python -m pip install -r docs/requirements.txt
-
-    - name: Configure
-      run: |
-        cmake -S . -B build -DDOWNLOAD_CATCH=ON \
-                            -DCMAKE_CXX_STANDARD=${{ matrix.cxx_standard }} \
-                            -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2 --verbose
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-
-  inplace:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - uses: actions/setup-python@v5
-      with:
-        python-version: '3.12'
-
-    - name: Install package
-      run: |
-        python -m pip install --upgrade pip
-        python -m pip install .
-
-    - name: Run tests with installed package
-      run: |
-        python -m pip install pytest pytest-timeout
-        pytest -v tests
-
-
-  manylinux:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Build manylinux wheels
-      run: |
-        docker run --rm -v ${{ github.workspace }}:/io quay.io/pypa/manylinux2014_x86_64 /io/tools/build_wheels.sh
-
-
-  deadsnakes:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-    - name: Setup deadsnakes Python versions
-      run: |
-        sudo add-apt-repository ppa:deadsnakes/ppa -y
-        sudo apt-get update -y
-        sudo apt-get install -y python3.7 python3.8 python3.9
-
-
-  clang:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
-
-  cuda:
-    if: github.event.pull_request.draft == false
-    runs-on: ubuntu-latest
-    timeout-minutes: 90
-
-    steps:
-    - uses: actions/checkout@v6
-
 
+  # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
     name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
 
     env:
+      # tzdata will try to ask for the timezone, so set the DEBIAN_FRONTEND
       DEBIAN_FRONTEND: 'noninteractive'
     steps:
     - uses: actions/checkout@v6
@@ -191,6 +54,8 @@ jobs:
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade pytest
 
+    # On some systems, you many need further workarounds:
+    # https://github.com/pybind/pybind11/pull/2475
     - name: Configure
       shell: bash
       run: |
@@ -216,6 +81,3 @@ jobs:
 
     - name: Visibility test
       run: cmake --build build --target test_cross_module_rtti
-
-
-  # Other jobs (gcc, icc, centos, windows, etc.) remain unchanged below...

From 351df4826f1188accb84a6971b292cf7f15df125 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 09:42:20 -0800
Subject: [PATCH 19/24] Change runner to ubuntu-24.04

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 22b22d2939..60de54614a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -30,7 +30,7 @@ jobs:
   # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
 

From 7419dd0c576874ab69848c0c4953d27c056079d0 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 09:50:14 -0800
Subject: [PATCH 20/24] Use nvhpc-25-11

---
 .github/workflows/ci.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 60de54614a..9329e76bad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -31,7 +31,7 @@ jobs:
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-24.04
-    name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
+    name: "🐍 3 • NVHPC 25.11 • C++17 • x64"
     timeout-minutes: 90
 
     env:
@@ -49,7 +49,7 @@ jobs:
       run: |
         sudo apt-get update -y && \
         sudo apt-get install -y cmake environment-modules git python3-dev python3-pip python3-numpy && \
-        sudo apt-get install -y --no-install-recommends nvhpc-23-5 && \
+        sudo apt-get install -y --no-install-recommends nvhpc-25-11 && \
         sudo rm -rf /var/lib/apt/lists/*
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade pytest
@@ -60,7 +60,7 @@ jobs:
       shell: bash
       run: |
         source /etc/profile.d/modules.sh
-        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/23.5
+        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/25.11
         cmake -S . -B build -DDOWNLOAD_CATCH=ON \
                             -DCMAKE_CXX_STANDARD=17 \
                             -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)") \
@@ -68,7 +68,7 @@ jobs:
                             -DPYBIND11_TEST_FILTER="test_smart_ptr.cpp"
 
     - name: Build
-      run: cmake --build build -j 2 --verbose
+      run: cmake --build build -j $(nproc) --verbose
 
     - name: Python tests
       run: cmake --build build --target pytest

From 6885af593eea025fe40c7dbc88e3177c354a7d24 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 17:35:38 -0800
Subject: [PATCH 21/24] Undo ALL changes relative to master (i.e. this branch
 is now an exact copy of master)

---
 .appveyor.yml                    |    2 -
 .github/workflows/ci.yml         | 1265 +++++++++++++++++++++++++++++-
 .github/workflows/configure.yml  |   85 ++
 .github/workflows/docs-link.yml  |   41 +
 .github/workflows/format.yml     |   54 ++
 .github/workflows/nightlies.yml  |   59 ++
 .github/workflows/pip.yml        |  118 +++
 .github/workflows/tests-cibw.yml |   95 +++
 .github/workflows/upstream.yml   |  116 +++
 tests/test_with_catch/catch.cpp  |   53 --
 10 files changed, 1828 insertions(+), 60 deletions(-)
 create mode 100644 .github/workflows/configure.yml
 create mode 100644 .github/workflows/docs-link.yml
 create mode 100644 .github/workflows/format.yml
 create mode 100644 .github/workflows/nightlies.yml
 create mode 100644 .github/workflows/pip.yml
 create mode 100644 .github/workflows/tests-cibw.yml
 create mode 100644 .github/workflows/upstream.yml

diff --git a/.appveyor.yml b/.appveyor.yml
index 833ec0e60a..391cf1071c 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -2,8 +2,6 @@ version: 1.0.{build}
 image:
 - Visual Studio 2017
 test: off
-skip_commits:
-  message: /.*/ # Skip ALL commits.
 skip_branch_with_pr: true
 build:
   parallel: true
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9329e76bad..d00ee6d27e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,12 +26,454 @@ env:
   CMAKE_COLOR_DIAGNOSTICS: 1
 
 jobs:
+  # This is the "main" test suite, which tests a large number of different
+  # versions of default compilers and Python versions in GitHub Actions.
+  # It is in two parts: one that always runs, and one that runs on non-draft
+  standard-small:
+    if: github.event.action != 'ready_for_review'
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - runs-on: ubuntu-22.04
+            python-version: '3.8'
+            cmake-args: -DPYBIND11_FINDPYTHON=OFF -DPYBIND11_NUMPY_1_ONLY=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.13'
+            cmake-args: -DCMAKE_CXX_STANDARD=23 -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.14t'
+            cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
+          - runs-on: ubuntu-latest
+            python-version: 'pypy3.11'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: 'graalpy-24.2'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: macos-latest
+            python-version: '3.14'
+            cmake-args: -DCMAKE_CXX_STANDARD=14
+          - runs-on: windows-2022
+            python-version: '3.8'
+            cmake-args: -DPYBIND11_FINDPYTHON=OFF
+
+
+    name: 🐍
+    uses: ./.github/workflows/reusable-standard.yml
+    with:
+      runs-on: ${{ matrix.runs-on }}
+      python-version: ${{ matrix.python-version }}
+      cmake-args: ${{ matrix.cmake-args }}
+
+  standard-large:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - runs-on: ubuntu-latest
+            python-version: '3.8'
+            cmake-args: -DPYBIND11_FINDPYTHON=ON -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: '3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: ubuntu-latest
+            python-version: '3.11'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: '3.12'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.13t'
+            cmake-args: -DCMAKE_CXX_STANDARD=20 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
+          - runs-on: ubuntu-latest
+            python-version: '3.14'
+            cmake-args: -DCMAKE_CXX_STANDARD=14 -DCMAKE_CXX_FLAGS="-DPYBIND11_HAS_SUBINTERPRETER_SUPPORT=0"
+          - runs-on: ubuntu-latest
+            python-version: 'pypy-3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=14
+          - runs-on: ubuntu-latest
+            python-version: 'graalpy-24.1'
+
+          # No SciPy for macOS ARM
+          - runs-on: macos-15-intel
+            python-version: '3.8'
+            cmake-args: -DCMAKE_CXX_STANDARD=14
+          - runs-on: macos-15-intel
+            python-version: '3.11'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
+          - runs-on: macos-latest
+            python-version: '3.12'
+            cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_DISABLE_HANDLE_TYPE_NAME_DEFAULT_IMPLEMENTATION=ON
+          - runs-on: macos-15-intel
+            python-version: '3.13t'
+            cmake-args: -DCMAKE_CXX_STANDARD=11
+          - runs-on: macos-latest
+            python-version: '3.14t'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: macos-15-intel
+            python-version: 'pypy-3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: macos-latest
+            python-version: 'pypy-3.11'
+          - runs-on: macos-latest
+            python-version: 'graalpy-24.2'
+
+          - runs-on: windows-latest
+            python-version: '3.9'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON
+          - runs-on: windows-2022
+            python-version: '3.8'
+            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded -DPYBIND11_NUMPY_1_ONLY=ON
+          - runs-on: windows-2022
+            python-version: '3.9'
+            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDLL -DCMAKE_CXX_STANDARD=14
+          # This needs a python built with MTd
+          # - runs-on: windows-2022
+          #   python-version: '3.11'
+          #   cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebug
+          - runs-on: windows-2022
+            python-version: '3.10'
+            cmake-args: -DPYBIND11_TEST_SMART_HOLDER=ON -DCMAKE_CXX_FLAGS="/GR /EHsc"
+          - runs-on: windows-2022
+            python-version: '3.13'
+            cmake-args: -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDebugDLL
+          - runs-on: windows-latest
+            python-version: '3.13t'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: windows-latest
+            python-version: '3.14'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: windows-latest
+            python-version: '3.14t'
+            cmake-args: -DCMAKE_CXX_STANDARD=23
+          - runs-on: windows-latest
+            python-version: 'pypy-3.10'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: windows-latest
+            python-version: 'pypy3.11'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
+          # The setup-python action currently doesn't have graalpy for windows
+          # See https://github.com/actions/setup-python/pull/880
+
+    name: 🐍
+    uses: ./.github/workflows/reusable-standard.yml
+    with:
+      runs-on: ${{ matrix.runs-on }}
+      python-version: ${{ matrix.python-version }}
+      cmake-args: ${{ matrix.cmake-args }}
+
+  # This checks inplace builds with C++11
+  inplace:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - runs-on: ubuntu-latest
+            python-version: '3.9'
+          - runs-on: macos-latest
+            python-version: '3.12'
+          - runs-on: windows-latest
+            python-version: '3.11'
+
+    name: "🐍 ${{ matrix.python-version }} • ${{ matrix.runs-on }} • x64 inplace C++14"
+    runs-on: ${{ matrix.runs-on }}
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v6
+      with:
+        python-version: ${{ matrix.python-version }}
+        allow-prereleases: true
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+      with:
+        enable-cache: true
+
+    - name: Prepare env
+      run: uv pip install --python=python --system -r tests/requirements.txt
+
+    # TODO Resolve Windows Ninja shared object issue on Python 3.8+
+    - name: Use Ninja except on Windows
+      if: runner.os != 'Windows'
+      run: echo "CMAKE_GENERATOR=Ninja" >> "$GITHUB_ENV"
+
+    # More-or-less randomly adding a few extra flags here.
+    # In particular, use this one to test the next ABI bump (internals version).
+    - name: Configure
+      run: >
+        cmake -S. -B.
+        -DPYBIND11_WERROR=ON
+        -DPYBIND11_SIMPLE_GIL_MANAGEMENT=ON
+        -DPYBIND11_PYTEST_ARGS=-v
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=14
+        -DPYBIND11_INTERNALS_VERSION=10000000
+
+    # Checks to makes sure defining `_` is allowed
+    # Triggers EHsc missing error on Windows
+    - name: Add underscore check
+      if: runner.os != 'Windows'
+      run: cmake -S. -B. -DCMAKE_CXX_FLAGS="-D_=1"
+
+    - name: Build
+      run: cmake --build .
+
+    - name: Python tests
+      run: cmake --build . --target pytest
+
+    - name: Compiled tests
+      run: cmake --build . --target cpptest
+
+    - name: Interface test
+      run: cmake --build . --target test_cmake_build
+
+    - name: Visibility test
+      run: cmake --build . --target test_cross_module_rtti
+
+
+  manylinux:
+    name: Manylinux on 🐍 3.13t • GIL
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-latest
+    timeout-minutes: 40
+    container: quay.io/pypa/musllinux_1_2_x86_64:latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Prepare uv's path
+        run: echo "$HOME/.local/bin" >> $GITHUB_PATH
+
+      - name: Install ninja
+        run: uv tool install ninja
+
+      - name: Configure via preset
+        run: cmake --preset venv -DPYBIND11_CREATE_WITH_UV=python3.13t
+
+      - name: Build C++11
+        run: cmake --build --preset venv
+
+      - name: Python tests C++11
+        run: cmake --build --preset testsvenv -t pytest
+
+  deadsnakes:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        # TODO: Fails on 3.10, investigate
+        # JOB DISABLED (NEEDS WORK): https://github.com/pybind/pybind11/issues/4889
+        # - python-version: "3.9"
+        #   python-debug: true
+        #   valgrind: true
+        - python-version: "3.11"
+          python-debug: false
+
+    name: "🐍 ${{ matrix.python-version }}${{ matrix.python-debug && '-dbg' || '' }} (deadsnakes)${{ matrix.valgrind && ' • Valgrind' || '' }} • x64"
+    runs-on: ubuntu-latest
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python ${{ matrix.python-version }} (deadsnakes)
+      uses: deadsnakes/action@v3.2.0
+      with:
+        python-version: ${{ matrix.python-version }}
+        debug: ${{ matrix.python-debug }}
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Valgrind cache
+      if: matrix.valgrind
+      uses: actions/cache@v4
+      id: cache-valgrind
+      with:
+        path: valgrind
+        key: 3.16.1 # Valgrind version
+
+    - name: Compile Valgrind
+      if: matrix.valgrind && steps.cache-valgrind.outputs.cache-hit != 'true'
+      run: |
+        VALGRIND_VERSION=3.16.1
+        curl https://sourceware.org/pub/valgrind/valgrind-$VALGRIND_VERSION.tar.bz2 -o - | tar xj
+        mv valgrind-$VALGRIND_VERSION valgrind
+        cd valgrind
+        ./configure
+        make -j 2 > /dev/null
+
+    - name: Install Valgrind
+      if: matrix.valgrind
+      working-directory: valgrind
+      run: |
+        sudo make install
+        sudo apt-get update
+        sudo apt-get install ninja-build libc6-dbg
+
+    - name: Prepare env
+      run: |
+        python -m pip install -r tests/requirements.txt
+
+    - name: Configure
+      run: cmake --preset default -DCMAKE_CXX_STANDARD=17
+
+    - name: Build
+      run: cmake --build --preset default
+
+    - name: Python tests
+      run: cmake --build --preset default --target pytest
+
+    - name: C++ tests
+      run: cmake --build --preset default --target cpptest
+
+    - name: Visibility test
+      run: cmake --build --preset default --target test_cross_module_rtti
+
+    - name: Run Valgrind on Python tests
+      if: matrix.valgrind
+      run: cmake --build --preset default --target memcheck
+
+
+  # Testing on clang using the excellent silkeh clang docker images
+  clang:
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - clang: 5
+            std: 14
+          - clang: 11
+            std: 20
+          - clang: 14
+            std: 20
+          - clang: 16
+            std: 20
+            container_suffix: "-bullseye"
+          - clang: 18
+            std: 20
+            cxx_flags: "-Werror -Wall -Wextra -Wwrite-strings -Wunreachable-code -Wpointer-arith -Wredundant-decls"
+            container_suffix: "-bookworm"
+
+    name: "🐍 3 • Clang ${{ matrix.clang }} • C++${{ matrix.std }} • x64${{ matrix.cxx_flags && ' • cxx_flags' || '' }}"
+    container: "silkeh/clang:${{ matrix.clang }}${{ matrix.container_suffix }}"
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Add wget and python3
+      run: apt-get update && apt-get install -y python3-dev python3-numpy python3-pytest libeigen3-dev
+
+    - name: Configure
+      shell: bash
+      run: >
+        cmake -S . -B build
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
+        -DCMAKE_CXX_FLAGS="${{ matrix.cxx_flags }}"
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+    - name: Build
+      run: cmake --build build -j 2
+
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+    - name: C++ tests
+      run: cmake --build build --target cpptest
+
+    - name: Interface test
+      run: cmake --build build --target test_cmake_build
+
+    - name: Visibility test
+      run: cmake --build build --target test_cross_module_rtti
+
+  # Testing NVCC; forces sources to behave like .cu files
+  cuda:
+    runs-on: ubuntu-latest
+    name: "🐍 3.10 • CUDA 12.2 • Ubuntu 22.04"
+    container: nvidia/cuda:12.2.0-devel-ubuntu22.04
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    # tzdata will try to ask for the timezone, so set the DEBIAN_FRONTEND
+    - name: Install 🐍 3
+      run: apt-get update && DEBIAN_FRONTEND="noninteractive" apt-get install -y cmake git python3-dev python3-pytest python3-numpy
+
+    - name: Configure
+      run: cmake -S . -B build -DPYBIND11_CUDA_TESTS=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+
+    - name: Build
+      run: cmake --build build -j2 --verbose
+
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+
+# TODO: Internal compiler error - report to NVidia
+#  # Testing CentOS 8 + PGI compilers
+#  centos-nvhpc8:
+#    runs-on: ubuntu-latest
+#    name: "🐍 3 • CentOS8 / PGI 20.11 • x64"
+#    container: centos:8
+#
+#    steps:
+#    - uses: actions/checkout@v6
+#
+#    - name: Add Python 3 and a few requirements
+#      run: yum update -y && yum install -y git python3-devel python3-numpy python3-pytest make environment-modules
+#
+#    - name: Install CMake with pip
+#      run: |
+#        python3 -m pip install --upgrade pip
+#        python3 -m pip install cmake --prefer-binary
+#
+#    - name: Install NVidia HPC SDK
+#      run: >
+#        yum -y install
+#        https://developer.download.nvidia.com/hpc-sdk/20.11/nvhpc-20-11-20.11-1.x86_64.rpm
+#        https://developer.download.nvidia.com/hpc-sdk/20.11/nvhpc-2020-20.11-1.x86_64.rpm
+#
+#    - name: Configure
+#      shell: bash
+#      run: |
+#        source /etc/profile.d/modules.sh
+#        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/20.11
+#        cmake -S . -B build -DDOWNLOAD_CATCH=ON -DCMAKE_CXX_STANDARD=14 -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+#
+#    - name: Build
+#      run: cmake --build build -j 2 --verbose
+#
+#    - name: Python tests
+#      run: cmake --build build --target pytest
+#
+#    - name: C++ tests
+#      run: cmake --build build --target cpptest
+#
+#    - name: Interface test
+#      run: cmake --build build --target test_cmake_build
+
 
   # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-24.04
-    name: "🐍 3 • NVHPC 25.11 • C++17 • x64"
+    runs-on: ubuntu-22.04
+    name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
 
     env:
@@ -49,7 +491,7 @@ jobs:
       run: |
         sudo apt-get update -y && \
         sudo apt-get install -y cmake environment-modules git python3-dev python3-pip python3-numpy && \
-        sudo apt-get install -y --no-install-recommends nvhpc-25-11 && \
+        sudo apt-get install -y --no-install-recommends nvhpc-23-5 && \
         sudo rm -rf /var/lib/apt/lists/*
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade pytest
@@ -60,7 +502,7 @@ jobs:
       shell: bash
       run: |
         source /etc/profile.d/modules.sh
-        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/25.11
+        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/23.5
         cmake -S . -B build -DDOWNLOAD_CATCH=ON \
                             -DCMAKE_CXX_STANDARD=17 \
                             -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)") \
@@ -68,7 +510,7 @@ jobs:
                             -DPYBIND11_TEST_FILTER="test_smart_ptr.cpp"
 
     - name: Build
-      run: cmake --build build -j $(nproc) --verbose
+      run: cmake --build build -j 2 --verbose
 
     - name: Python tests
       run: cmake --build build --target pytest
@@ -81,3 +523,816 @@ jobs:
 
     - name: Visibility test
       run: cmake --build build --target test_cross_module_rtti
+
+  # Testing on GCC using the GCC docker images (only recent images supported)
+  gcc:
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { gcc: 9, std: 20 }
+          - { gcc: 10, std: 17 }
+          - { gcc: 10, std: 20 }
+          - { gcc: 13, std: 20, cxx_flags: "-Wall -Wextra -Wwrite-strings -Wunreachable-code -Wpointer-arith -Wredundant-decls" }
+
+    name: "🐍 3 • GCC ${{ matrix.gcc }} • C++${{ matrix.std }} • x64${{ matrix.cxx_flags && ' • cxx_flags' || '' }}"
+    container: "gcc:${{ matrix.gcc }}"
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Add Python 3
+      run: apt-get update; apt-get install -y python3-dev python3-numpy python3-pytest python3-pip libeigen3-dev
+
+    - name: Update pip
+      run: python3 -m pip install --upgrade pip
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Configure
+      shell: bash
+      run: >
+        cmake -S . -B build
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
+        -DCMAKE_CXX_FLAGS="${{ matrix.cxx_flags }}"
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+    - name: Build
+      run: cmake --build build -j 2
+
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+    - name: C++ tests
+      run: cmake --build build --target cpptest
+
+    - name: Interface test
+      run: cmake --build build --target test_cmake_build
+
+    - name: Visibility test
+      run: cmake --build build --target test_cross_module_rtti
+
+    - name: Configure - Exercise cmake -DPYBIND11_TEST_OVERRIDE
+      if: matrix.gcc == '12'
+      shell: bash
+      run: >
+        cmake -S . -B build_partial
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+        "-DPYBIND11_TEST_OVERRIDE=test_call_policies.cpp;test_gil_scoped.cpp;test_thread.cpp"
+
+    - name: Build - Exercise cmake -DPYBIND11_TEST_OVERRIDE
+      if: matrix.gcc == '12'
+      run: cmake --build build_partial -j 2
+
+    - name: Python tests - Exercise cmake -DPYBIND11_TEST_OVERRIDE
+      if: matrix.gcc == '12'
+      run: cmake --build build_partial --target pytest
+
+  # Testing on ICC using the oneAPI apt repo
+  icc:
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-22.04
+    timeout-minutes: 90
+
+    name: "🐍 3 • ICC latest • x64"
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Add apt repo
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y wget build-essential pkg-config cmake ca-certificates gnupg
+        wget https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS-2023.PUB
+        sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS-2023.PUB
+        echo "deb https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
+
+    - name: Add ICC & Python 3
+      run: sudo apt-get update; sudo apt-get install -y intel-oneapi-compiler-dpcpp-cpp-and-cpp-classic cmake python3-dev python3-numpy python3-pytest python3-pip
+
+    - name: Update pip
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        python3 -m pip install --upgrade pip
+
+    - name: Install dependencies
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        python3 -m pip install -r tests/requirements.txt
+
+    - name: Configure C++11
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake -S . -B build-11     \
+        -DPYBIND11_WERROR=ON    \
+        -DDOWNLOAD_CATCH=ON     \
+        -DDOWNLOAD_EIGEN=OFF    \
+        -DCMAKE_CXX_STANDARD=11             \
+        -DCMAKE_CXX_COMPILER=$(which icpc)  \
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+    - name: Build C++11
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-11 -j 2 -v
+
+    - name: Python tests C++11
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        sudo service apport stop
+        cmake --build build-11 --target check
+
+    - name: C++ tests C++11
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-11 --target cpptest
+
+    - name: Interface test C++11
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-11 --target test_cmake_build
+
+    - name: Visibility test
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-11 --target test_cross_module_rtti
+
+    - name: Configure C++17
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake -S . -B build-17     \
+        -DPYBIND11_WERROR=ON    \
+        -DDOWNLOAD_CATCH=ON     \
+        -DDOWNLOAD_EIGEN=OFF    \
+        -DCMAKE_CXX_STANDARD=17             \
+        -DCMAKE_CXX_COMPILER=$(which icpc)  \
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+    - name: Build C++17
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-17 -j 2 -v
+
+    - name: Python tests C++17
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        sudo service apport stop
+        cmake --build build-17 --target check
+
+    - name: C++ tests C++17
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-17 --target cpptest
+
+    - name: Interface test C++17
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-17 --target test_cmake_build
+
+    - name: Visibility test
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        cmake --build build-17 --target test_cross_module_rtti
+
+  # Testing on CentOS (manylinux uses a centos base).
+  centos:
+    if: github.event.pull_request.draft == false
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        container:
+          - "almalinux:8"
+          - "almalinux:9"
+
+    name: "🐍 3 • ${{ matrix.container }} • x64"
+    container: "${{ matrix.container }}"
+    timeout-minutes: 90
+
+    steps:
+    - name: Latest actions/checkout
+      uses: actions/checkout@v6
+
+    - name: Add Python 3.8
+      if: matrix.container == 'almalinux:8'
+      run: dnf update -y && dnf install -y python38-devel gcc-c++ make git
+
+    - name: Add Python 3 (default)
+      if: matrix.container != 'almalinux:8'
+      run: dnf update -y && dnf install -y python3-devel gcc-c++ make git
+
+    - name: Update pip
+      run: python3 -m pip install --upgrade pip
+
+    - name: Install dependencies
+      run: |
+        python3 -m pip install cmake -r tests/requirements.txt
+
+    - name: Ensure NumPy 2 is used (required Python >= 3.9)
+      if: matrix.container == 'almalinux:9'
+      run: |
+        python3 -m pip install 'numpy>=2.0.0b1' 'scipy>=1.13.0rc1'
+
+    - name: Configure
+      shell: bash
+      run: >
+        cmake -S . -B build
+        -DCMAKE_BUILD_TYPE=MinSizeRel
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=11
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+    - name: Build
+      run: cmake --build build -j 2
+
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+    - name: C++ tests
+      run: cmake --build build --target cpptest
+
+    - name: Interface test
+      run: cmake --build build --target test_cmake_build
+
+    - name: Visibility test
+      run: cmake --build build --target test_cross_module_rtti
+
+
+  # This tests an "install" with the CMake tools
+  install-classic:
+    if: github.event.pull_request.draft == false
+    name: "🐍 3.9 • Debian • x86 •  Install"
+    runs-on: ubuntu-latest
+    container: i386/debian:bullseye
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v1  # v1 is required to run inside docker
+
+    - name: Install requirements
+      run: |
+        apt-get update
+        apt-get install -y git make cmake g++ libeigen3-dev python3-dev python3-pip
+        pip3 install "pytest==6.*"
+
+    - name: Configure for install
+      run: >
+        cmake .
+        -DPYBIND11_INSTALL=1 -DPYBIND11_TEST=0
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+
+    - name: Make and install
+      run: make install
+
+    - name: Copy tests to new directory
+      run: cp -a tests /pybind11-tests
+
+    - name: Make a new test directory
+      run: mkdir /build-tests
+
+    - name: Configure tests
+      run: >
+        cmake ../pybind11-tests
+        -DDOWNLOAD_CATCH=ON
+        -DPYBIND11_WERROR=ON
+        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
+      working-directory: /build-tests
+
+    - name: Python tests
+      run: make pytest -j 2
+      working-directory: /build-tests
+
+
+  # This verifies that the documentation is not horribly broken, and does a
+  # basic validation check on the SDist.
+  doxygen:
+    if: github.event.pull_request.draft == false
+    name: "Documentation build test"
+    runs-on: ubuntu-latest
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - uses: actions/setup-python@v6
+      with:
+        python-version: "3.x"
+
+    - name: Install Doxygen
+      run: sudo apt-get install -y doxygen librsvg2-bin # Changed to rsvg-convert in 20.04
+
+    - name: Build docs
+      run: pipx run nox -s docs
+
+    - name: Make SDist
+      run: pipx run nox -s build -- --sdist
+
+    - run: git status --ignored
+
+    - name: Check local include dir
+      run: >
+        ls pybind11;
+        python3 -c "import pybind11, pathlib; assert (a := pybind11.get_include()) == (b := str(pathlib.Path('include').resolve())), f'{a} != {b}'"
+
+    - name: Compare Dists (headers only)
+      working-directory: include
+      run: |
+        python3 -m pip install --user -U ../dist/*.tar.gz
+        installed=$(python3 -c "import pybind11; print(pybind11.get_include() + '/pybind11')")
+        diff -rq $installed ./pybind11
+
+  win32:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - python: '3.8'
+            args: -DCMAKE_CXX_STANDARD=17
+          - python: '3.10'
+            args: -DCMAKE_CXX_STANDARD=20
+          - python: '3.13'
+
+
+    name: "🐍 ${{ matrix.python }} • MSVC 2022 • x86 ${{ matrix.args }}"
+    runs-on: windows-2022
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python ${{ matrix.python }}
+      uses: actions/setup-python@v6
+      with:
+        python-version: ${{ matrix.python }}
+        architecture: x86
+        # Python 3.13.4 broken on Windows
+        check-latest: >-
+          ${{ matrix.python == '3.13' && runner.os == 'Windows' }}
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Prepare MSVC
+      uses: ilammy/msvc-dev-cmd@v1.13.0
+      with:
+        arch: x86
+
+    - name: Prepare env
+      run: |
+        python -m pip install -r tests/requirements.txt
+
+    - name: Configure ${{ matrix.args }}
+      run: >
+        cmake -S . -B build
+        -G "Visual Studio 17 2022" -A Win32
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        ${{ matrix.args }}
+    - name: Build C++11
+      run: cmake --build build -j 2
+
+    - name: Python tests
+      run: cmake --build build -t pytest
+
+  win32-debug:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - python: 3.9
+            args: -DCMAKE_CXX_STANDARD=20
+          - python: 3.8
+            args: -DCMAKE_CXX_STANDARD=17
+
+    name: "🐍 ${{ matrix.python }} • MSVC 2022 (Debug) • x86 ${{ matrix.args }}"
+    runs-on: windows-2022
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python ${{ matrix.python }}
+      uses: actions/setup-python@v6
+      with:
+        python-version: ${{ matrix.python }}
+        architecture: x86
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Prepare MSVC
+      uses: ilammy/msvc-dev-cmd@v1.13.0
+      with:
+        arch: x86
+
+    - name: Prepare env
+      run: |
+        python -m pip install -r tests/requirements.txt
+
+    - name: Configure ${{ matrix.args }}
+      run: >
+        cmake -S . -B build
+        -G "Visual Studio 17 2022" -A Win32
+        -DCMAKE_BUILD_TYPE=Debug
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        ${{ matrix.args }}
+    - name: Build C++11
+      run: cmake --build build --config Debug -j 2
+
+    - name: Python tests
+      run: cmake --build build --config Debug -t pytest
+
+
+  windows-2022:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        python:
+        - 3.9
+
+    name: "🐍 ${{ matrix.python }} • MSVC 2022 C++20 • x64"
+    runs-on: windows-2022
+    timeout-minutes: 90
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python ${{ matrix.python }}
+      uses: actions/setup-python@v6
+      with:
+        python-version: ${{ matrix.python }}
+
+    - name: Prepare env
+      run: python3 -m pip install -r tests/requirements.txt
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Configure C++20
+      run: >
+        cmake -S . -B build
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=20
+
+    - name: Build C++20
+      run: cmake --build build -j 2
+
+    - name: Python tests
+      run: cmake --build build --target pytest
+
+    - name: C++20 tests
+      run: cmake --build build --target cpptest -j 2
+
+    - name: Interface test C++20
+      run: cmake --build build --target test_cmake_build
+
+    - name: Visibility test
+      run: cmake --build build --target test_cross_module_rtti
+
+    - name: Configure C++20 - Exercise cmake -DPYBIND11_TEST_OVERRIDE
+      run: >
+        cmake -S . -B build_partial
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=20
+        "-DPYBIND11_TEST_OVERRIDE=test_call_policies.cpp;test_gil_scoped.cpp;test_thread.cpp"
+
+    - name: Build C++20 - Exercise cmake -DPYBIND11_TEST_OVERRIDE
+      run: cmake --build build_partial -j 2
+
+    - name: Python tests - Exercise cmake -DPYBIND11_TEST_OVERRIDE
+      run: cmake --build build_partial --target pytest
+
+  mingw:
+    if: github.event.pull_request.draft == false
+    name: "🐍 3 • windows-latest • ${{ matrix.sys }}"
+    runs-on: windows-latest
+    timeout-minutes: 90
+    defaults:
+      run:
+        shell: msys2 {0}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - sys: mingw32
+            env: i686
+            extra_install: ""
+          - sys: mingw64
+            env: x86_64
+            extra_install: |
+              mingw-w64-x86_64-python-numpy
+              mingw-w64-x86_64-python-scipy
+              mingw-w64-x86_64-eigen3
+    steps:
+    - uses: msys2/setup-msys2@v2
+      with:
+        msystem: ${{matrix.sys}}
+        install: >-
+          git
+          mingw-w64-${{matrix.env}}-gcc
+          mingw-w64-${{matrix.env}}-python-pip
+          mingw-w64-${{matrix.env}}-cmake
+          mingw-w64-${{matrix.env}}-make
+          mingw-w64-${{matrix.env}}-python-pytest
+          mingw-w64-${{matrix.env}}-boost
+          mingw-w64-${{matrix.env}}-catch
+          ${{ matrix.extra_install }}
+
+    - uses: actions/checkout@v6
+
+    - name: Configure C++11
+      # LTO leads to many undefined reference like
+      # `pybind11::detail::function_call::function_call(pybind11::detail::function_call&&)
+      run: >-
+        cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=11 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+        -S . -B build
+
+    - name: Build C++11
+      run: cmake --build build -j 2
+
+    - name: Python tests C++11
+      run: cmake --build build --target pytest -j 2
+
+    - name: C++11 tests
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build --target cpptest -j 2
+
+    - name: Interface test C++11
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build --target test_cmake_build
+
+    - name: Visibility test
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build --target test_cross_module_rtti
+
+    - name: Clean directory
+      run: git clean -fdx
+
+    - name: Configure C++14
+      run: >-
+        cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=14 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+        -S . -B build2
+
+    - name: Build C++14
+      run: cmake --build build2 -j 2
+
+    - name: Python tests C++14
+      run: cmake --build build2 --target pytest -j 2
+
+    - name: C++14 tests
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build2 --target cpptest -j 2
+
+    - name: Interface test C++14
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build2 --target test_cmake_build
+
+    - name: Visibility test
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build2 --target test_cross_module_rtti
+
+    - name: Clean directory
+      run: git clean -fdx
+
+    - name: Configure C++17
+      run: >-
+        cmake -G "MinGW Makefiles" -DCMAKE_CXX_STANDARD=17 -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+        -S . -B build3
+
+    - name: Build C++17
+      run: cmake --build build3 -j 2
+
+    - name: Python tests C++17
+      run: cmake --build build3 --target pytest -j 2
+
+    - name: C++17 tests
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target cpptest -j 2
+
+    - name: Interface test C++17
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cmake_build
+
+    - name: Visibility test
+      run: PYTHONHOME=/${{matrix.sys}} PYTHONPATH=/${{matrix.sys}} cmake --build build3 --target test_cross_module_rtti
+
+  windows_clang:
+    if: github.event.pull_request.draft == false
+
+    strategy:
+      matrix:
+        os: [windows-latest]
+        python: ['3.10']
+
+    runs-on: "${{ matrix.os }}"
+    timeout-minutes: 90
+
+    name: "🐍 ${{ matrix.python }} • ${{ matrix.os }} • clang-latest"
+
+    steps:
+      - name: Show env
+        run: env
+
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Set up Clang
+        uses: egor-tensin/setup-clang@v1
+
+      - name: Setup Python ${{ matrix.python }}
+        uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python }}
+
+      - name: Update CMake
+        uses: jwlawson/actions-setup-cmake@v2.0
+
+      - name: Install ninja-build tool
+        uses: seanmiddleditch/gha-setup-ninja@v6
+
+      - name: Run pip installs
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r tests/requirements.txt
+
+      - name: Show Clang++ version
+        run: clang++ --version
+
+      - name: Show CMake version
+        run: cmake --version
+
+      # TODO: WERROR=ON
+      - name: Configure Clang
+        run: >
+          cmake -G Ninja -S . -B .
+          -DPYBIND11_WERROR=OFF
+          -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
+          -DDOWNLOAD_CATCH=ON
+          -DDOWNLOAD_EIGEN=ON
+          -DCMAKE_CXX_COMPILER=clang++
+          -DCMAKE_CXX_STANDARD=17
+
+      - name: Build
+        run: cmake --build . -j 2
+
+      - name: Python tests
+        run: cmake --build . --target pytest -j 2
+
+      - name: C++ tests
+        run: cmake --build . --target cpptest -j 2
+
+      - name: Interface test
+        run: cmake --build . --target test_cmake_build -j 2
+
+      - name: Visibility test
+        run: cmake --build . --target test_cross_module_rtti -j 2
+
+      - name: Clean directory
+        run: git clean -fdx
+
+  # Clang with MSVC/Windows SDK toolchain + python.org CPython (Windows ARM)
+  windows_arm_clang_msvc:
+    if: github.event.pull_request.draft == false
+
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-11-arm]
+        python: ['3.13']
+
+    runs-on: "${{ matrix.os }}"
+    timeout-minutes: 90
+
+    name: "🐍 ${{ matrix.python }} • ${{ matrix.os }} • clang-msvc"
+
+    steps:
+      - name: Show env
+        run: env
+
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Python ${{ matrix.python }}
+        uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python }}
+          architecture: arm64
+
+      - name: Run pip installs
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r tests/requirements.txt
+
+      - name: Configure CMake
+        run: >
+          cmake -G Ninja -S . -B .
+          -DPYBIND11_WERROR=OFF
+          -DPYBIND11_SIMPLE_GIL_MANAGEMENT=OFF
+          -DDOWNLOAD_CATCH=ON
+          -DDOWNLOAD_EIGEN=ON
+          -DCMAKE_CXX_COMPILER=clang++
+          -DCMAKE_CXX_STANDARD=20
+          -DPython_ROOT_DIR="$env:Python_ROOT_DIR"
+
+      - name: Build
+        run: cmake --build . -j 2
+
+      - name: Python tests
+        run: cmake --build . --target pytest -j 2
+
+      - name: C++ tests
+        run: cmake --build . --target cpptest -j 2
+
+      - name: Interface test
+        run: cmake --build . --target test_cmake_build -j 2
+
+      - name: Visibility test
+        run: cmake --build . --target test_cross_module_rtti -j 2
+
+  # Clang in MSYS2/MinGW-w64 CLANGARM64 toolchain + MSYS2 Python (Windows ARM)
+  windows_arm_clang_msys2:
+    if: github.event.pull_request.draft == false
+
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-11-arm]
+
+    runs-on: "${{ matrix.os }}"
+    timeout-minutes: 90
+
+    name: "${{ matrix.os }} • clang-msys2"
+
+    defaults:
+      run:
+        shell: msys2 {0}
+
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+
+    - uses: msys2/setup-msys2@v2
+      with:
+        msystem: CLANGARM64
+        update: true
+        install: |
+          mingw-w64-clang-aarch64-cmake
+          mingw-w64-clang-aarch64-clang
+          mingw-w64-clang-aarch64-ninja
+          mingw-w64-clang-aarch64-python-pip
+          mingw-w64-clang-aarch64-python-pytest
+          mingw-w64-clang-aarch64-python-numpy
+
+    - name: Debug info
+      run: |
+        clang++ --version
+        cmake --version
+        ninja --version
+        python --version
+
+    - name: Run pip installs
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install -r tests/requirements.txt
+
+    - name: Configure CMake
+      run: >-
+        cmake -S . -B build
+        -DPYBIND11_WERROR=OFF
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_COMPILER=clang++
+        -DCMAKE_CXX_STANDARD=20
+        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
+
+    - name: Build
+      run: cmake --build build -j 2
+
+    - name: Python tests
+      run: cmake --build build --target pytest -j 2
+
+    - name: C++ tests
+      run: PYTHONHOME=/clangarm64 PYTHONPATH=/clangarm64 cmake --build build --target cpptest -j 2
+
+    - name: Interface test
+      run: cmake --build build --target test_cmake_build -j 2
+
+    - name: Visibility test
+      run: cmake --build build --target test_cross_module_rtti -j 2
diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
new file mode 100644
index 0000000000..cd034c883f
--- /dev/null
+++ b/.github/workflows/configure.yml
@@ -0,0 +1,85 @@
+name: Config
+
+on:
+  workflow_dispatch:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - ready_for_review
+  push:
+    branches:
+      - master
+      - stable
+      - v*
+
+permissions:
+  contents: read
+
+jobs:
+  # This tests various versions of CMake in various combinations, to make sure
+  # the configure step passes.
+  cmake:
+    if: github.event.pull_request.draft == false
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+        - runs-on: ubuntu-22.04
+          cmake: "3.15"
+
+        - runs-on: ubuntu-24.04
+          cmake: "3.26"
+
+        - runs-on: ubuntu-24.04
+          cmake: "3.29"
+
+        - runs-on: macos-15-intel
+          cmake: "3.15"
+
+        - runs-on: macos-14
+          cmake: "4.0"
+
+        - runs-on: windows-latest
+          cmake: "4.0"
+
+    name: 🐍 3.11 • CMake ${{ matrix.cmake }} • ${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python 3.11
+      uses: actions/setup-python@v6
+      with:
+        python-version: 3.11
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+
+    - name: Prepare env
+      run: uv pip install --python=python --system -r tests/requirements.txt
+
+    # An action for adding a specific version of CMake:
+    #   https://github.com/jwlawson/actions-setup-cmake
+    - name: Setup CMake ${{ matrix.cmake }}
+      uses: jwlawson/actions-setup-cmake@v2.0
+      with:
+        cmake-version: ${{ matrix.cmake }}
+
+    # These steps use a directory with a space in it intentionally
+    - name: Configure
+      shell: bash
+      run: cmake -S. -B"build dir" -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
+
+    # Only build and test if this was manually triggered in the GitHub UI
+    - name: Build
+      working-directory: build dir
+      if: github.event_name == 'workflow_dispatch'
+      run: cmake --build . --config Release
+
+    - name: Test
+      working-directory: build dir
+      if: github.event_name == 'workflow_dispatch'
+      run: cmake --build . --config Release --target check
diff --git a/.github/workflows/docs-link.yml b/.github/workflows/docs-link.yml
new file mode 100644
index 0000000000..ea25410cb9
--- /dev/null
+++ b/.github/workflows/docs-link.yml
@@ -0,0 +1,41 @@
+name: Read the Docs PR preview
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - synchronize
+
+permissions:
+  contents: read
+  pull-requests: write
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  documentation-links:
+    runs-on: ubuntu-latest
+    if: github.event.repository.fork == false
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Check for docs changes
+        id: docs_changes
+        run: |
+          # Fetch the PR head
+          git fetch origin pull/${{ github.event.pull_request.number }}/head:pr-head
+
+          # Show diff between base (current checkout) and PR head
+          if git diff --name-only HEAD pr-head | grep -q '^docs/'; then
+            echo "docs_changed=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "docs_changed=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - uses: readthedocs/actions/preview@v1
+        if: steps.docs_changes.outputs.docs_changed == 'true'
+        with:
+          project-slug: "pybind11"
+          single-version: "true"
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
new file mode 100644
index 0000000000..6bf77324a9
--- /dev/null
+++ b/.github/workflows/format.yml
@@ -0,0 +1,54 @@
+# This is a format job. Pre-commit has a first-party GitHub action, so we use
+# that: https://github.com/pre-commit/action
+
+name: Format
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+    - master
+    - stable
+    - "v*"
+
+permissions:
+  contents: read
+
+env:
+  FORCE_COLOR: 3
+  # For cmake:
+  VERBOSE: 1
+
+jobs:
+  pre-commit:
+    name: Format
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6
+    - uses: actions/setup-python@v6
+      with:
+        python-version: "3.x"
+    - name: Add matchers
+      run: echo "::add-matcher::$GITHUB_WORKSPACE/.github/matchers/pylint.json"
+    - uses: pre-commit/action@v3.0.1
+
+  clang-tidy:
+    # When making changes here, please also review the "Clang-Tidy" section
+    # in .github/CONTRIBUTING.md and update as needed.
+    name: Clang-Tidy
+    runs-on: ubuntu-latest
+    container: silkeh/clang:20
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Install requirements
+      run: apt-get update && apt-get install -y git python3-dev python3-pytest ninja-build
+
+    - name: Configure
+      run: cmake --preset tidy
+    - name: Build
+      run: cmake --build --preset tidy
+
+    - name: Embedded
+      run: cmake --build --preset tidy -t cpptest
diff --git a/.github/workflows/nightlies.yml b/.github/workflows/nightlies.yml
new file mode 100644
index 0000000000..ad4a351521
--- /dev/null
+++ b/.github/workflows/nightlies.yml
@@ -0,0 +1,59 @@
+name: Upload nightly wheels to Anaconda Cloud
+
+on:
+  # Run daily at 2:34 UTC to upload nightly wheels to Anaconda Cloud
+  schedule:
+    - cron: "34 2 * * *"
+  # Run on demand with workflow dispatch
+  workflow_dispatch:
+
+permissions:
+  actions: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build_wheel:
+    name: Build and upload wheel
+    if: github.repository_owner == 'pybind'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v7
+
+      - name: Build SDist and wheels
+        run: |
+          uv tool install nox
+          nox -s build
+          nox -s build_global
+
+      - uses: actions/upload-artifact@v5
+        with:
+          name: Packages
+          path: dist/*
+
+  upload_nightly_wheels:
+    name: Upload nightly wheels to Anaconda Cloud
+    if: github.repository_owner == 'pybind'
+    needs: [build_wheel]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/download-artifact@v6
+        with:
+          name: Packages
+          path: dist
+
+      - name: List wheel to be deployed
+        run: ls -lha dist/*.whl
+
+      - name: Upload wheel to Anaconda Cloud as nightly
+        uses: scientific-python/upload-nightly-action@b36e8c0c10dbcfd2e05bf95f17ef8c14fd708dbf # 0.6.2
+        with:
+          artifacts_path: dist
+          anaconda_nightly_upload_token: ${{ secrets.ANACONDA_ORG_UPLOAD_TOKEN }}
diff --git a/.github/workflows/pip.yml b/.github/workflows/pip.yml
new file mode 100644
index 0000000000..8df91a00fa
--- /dev/null
+++ b/.github/workflows/pip.yml
@@ -0,0 +1,118 @@
+name: Pip
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+    - master
+    - stable
+    - v*
+  release:
+    types:
+    - published
+
+permissions:
+  contents: read
+
+jobs:
+  # This builds the sdists and wheels and makes sure the files are exactly as
+  # expected.
+  test-packaging:
+    name: 🐍 3.8 • 📦 tests • windows-latest
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup 🐍 3.8
+      uses: actions/setup-python@v6
+      with:
+        python-version: 3.8
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+
+    - name: Prepare env
+      run: uv pip install --system -r tests/requirements.txt
+
+    - name: Python Packaging tests
+      run: pytest tests/extra_python_package/
+
+
+  # This runs the packaging tests and also builds and saves the packages as
+  # artifacts.
+  packaging:
+    name: 🐍 3.8 • 📦 & 📦 tests • ubuntu-latest
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup 🐍 3.8
+      uses: actions/setup-python@v6
+      with:
+        python-version: 3.8
+
+    - name: Install uv
+      uses: astral-sh/setup-uv@v7
+
+    - name: Prepare env
+      run: uv pip install --system -r tests/requirements.txt twine nox
+
+    - name: Python Packaging tests
+      run: pytest tests/extra_python_package/
+
+    - name: Build SDist and wheels
+      run: |
+        nox -s build
+        nox -s build_global
+
+    - name: Check metadata
+      run: twine check dist/*
+
+    - name: Save standard package
+      uses: actions/upload-artifact@v5
+      with:
+        name: standard
+        path: dist/pybind11-*
+
+    - name: Save global package
+      uses: actions/upload-artifact@v5
+      with:
+        name: global
+        path: dist/*global-*
+
+
+
+  # When a GitHub release is made, upload the artifacts to PyPI
+  upload:
+    name: Upload to PyPI
+    runs-on: ubuntu-latest
+    if: github.event_name == 'release' && github.event.action == 'published'
+    needs: [packaging]
+    environment:
+      name: pypi
+      url: https://pypi.org/p/pybind11
+    permissions:
+      id-token: write
+      attestations: write
+
+    steps:
+    # Downloads all to directories matching the artifact names
+    - uses: actions/download-artifact@v6
+
+    - name: Generate artifact attestation for sdist and wheel
+      uses: actions/attest-build-provenance@v3
+      with:
+        subject-path: "*/pybind11*"
+
+    - name: Publish standard package
+      uses: pypa/gh-action-pypi-publish@release/v1
+      with:
+        packages-dir: standard/
+
+    - name: Publish global package
+      uses: pypa/gh-action-pypi-publish@release/v1
+      with:
+        packages-dir: global/
diff --git a/.github/workflows/tests-cibw.yml b/.github/workflows/tests-cibw.yml
new file mode 100644
index 0000000000..5dfb5dc940
--- /dev/null
+++ b/.github/workflows/tests-cibw.yml
@@ -0,0 +1,95 @@
+name: CIBW
+
+on:
+  workflow_dispatch:
+  pull_request:
+    branches:
+    - master
+    - stable
+    - v*
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build-wasm-emscripten:
+    name: Pyodide wheel
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+        fetch-depth: 0
+
+    - uses: pypa/cibuildwheel@v3.3
+      env:
+        PYODIDE_BUILD_EXPORTS: whole_archive
+      with:
+        package-dir: tests
+        only: cp312-pyodide_wasm32
+
+  build-ios:
+    name: iOS wheel ${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        runs-on: [macos-14, macos-15-intel]
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+        fetch-depth: 0
+
+    # We have to uninstall first because GH is now using a local tap to build cmake<4, iOS needs cmake>=4
+    - run: brew uninstall cmake && brew install cmake
+
+    - uses: pypa/cibuildwheel@v3.3
+      env:
+        CIBW_PLATFORM: ios
+        CIBW_SKIP: cp314-*  # https://github.com/pypa/cibuildwheel/issues/2494
+      with:
+        package-dir: tests
+
+  build-android:
+    name: Android wheel ${{ matrix.runs-on }}
+    runs-on: ${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        runs-on: [macos-latest, macos-15-intel, ubuntu-latest]
+    steps:
+    - uses: actions/checkout@v6
+      with:
+        submodules: true
+        fetch-depth: 0
+
+    # GitHub Actions can't currently run the Android emulator on macOS.
+    - name: Skip Android tests on macOS
+      if: contains(matrix.runs-on, 'macos')
+      run: echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
+
+    # Temporarily disable Android tests on ubuntu-latest due to emulator issues.
+    # See https://github.com/pybind/pybind11/pull/5914.
+    - name: "NOTE: Android tests are disabled on ubuntu-latest"
+      if: contains(matrix.runs-on, 'ubuntu')
+      run: |
+        echo "CIBW_TEST_COMMAND=" >> "$GITHUB_ENV"
+        echo '::warning::Android cibuildwheel tests are disabled on ubuntu-latest (CIBW_TEST_COMMAND is empty). See PR 5914.'
+
+    # https://github.blog/changelog/2024-04-02-github-actions-hardware-accelerated-android-virtualization-now-available/
+    - name: Enable KVM for Android emulator
+      if: contains(matrix.runs-on, 'ubuntu')
+      run: |
+        echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+        sudo udevadm control --reload-rules
+        sudo udevadm trigger --name-match=kvm
+
+    - run: pipx install patchelf
+
+    - uses: pypa/cibuildwheel@v3.3
+      env:
+        CIBW_PLATFORM: android
+      with:
+        package-dir: tests
diff --git a/.github/workflows/upstream.yml b/.github/workflows/upstream.yml
new file mode 100644
index 0000000000..15ede7a856
--- /dev/null
+++ b/.github/workflows/upstream.yml
@@ -0,0 +1,116 @@
+name: Upstream
+
+on:
+  workflow_dispatch:
+  pull_request:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: upstream-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PIP_BREAK_SYSTEM_PACKAGES: 1
+  # For cmake:
+  VERBOSE: 1
+
+jobs:
+  standard:
+    name: "🐍 3.13 latest • ubuntu-latest • x64"
+    runs-on: ubuntu-latest
+    # Only runs when the  'python dev' label is selected
+    if: "contains(github.event.pull_request.labels.*.name, 'python dev')"
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Setup Python 3.13
+      uses: actions/setup-python@v6
+      with:
+        python-version: "3.13"
+        allow-prereleases: true
+
+    - name: Setup Boost
+      run: sudo apt-get install libboost-dev
+
+    - name: Update CMake
+      uses: jwlawson/actions-setup-cmake@v2.0
+
+    - name: Run pip installs
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install -r tests/requirements.txt
+
+    - name: Show platform info
+      run: |
+        python -m platform
+        cmake --version
+        pip list
+
+    # First build - C++11 mode and inplace
+    - name: Configure C++11
+      run: >
+        cmake -S . -B build11
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=11
+        -DCMAKE_BUILD_TYPE=Debug
+
+    - name: Build C++11
+      run: cmake --build build11 -j 2
+
+    - name: Python tests C++11
+      run: cmake --build build11 --target pytest -j 2
+
+    - name: C++11 tests
+      run: cmake --build build11  --target cpptest -j 2
+
+    - name: Interface test C++11
+      run: cmake --build build11 --target test_cmake_build
+
+    # Second build - C++17 mode and in a build directory
+    - name: Configure C++17
+      run: >
+        cmake -S . -B build17
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=17
+
+    - name: Build C++17
+      run: cmake --build build17 -j 2
+
+    - name: Python tests C++17
+      run: cmake --build build17 --target pytest
+
+    - name: C++17 tests
+      run: cmake --build build17 --target cpptest
+
+    # Third build - C++17 mode with unstable ABI
+    - name: Configure (unstable ABI)
+      run: >
+        cmake -S . -B build17max
+        -DPYBIND11_WERROR=ON
+        -DDOWNLOAD_CATCH=ON
+        -DDOWNLOAD_EIGEN=ON
+        -DCMAKE_CXX_STANDARD=17
+        -DPYBIND11_INTERNALS_VERSION=10000000
+
+    - name: Build (unstable ABI)
+      run: cmake --build build17max -j 2
+
+    - name: Python tests (unstable ABI)
+      run: cmake --build build17max --target pytest
+
+    - name: Interface test (unstable ABI)
+      run: cmake --build build17max --target test_cmake_build
+
+    # This makes sure the setup_helpers module can build packages using
+    # setuptools
+    - name: Setuptools helpers test
+      run: |
+        pip install setuptools
+        pytest tests/extra_setuptools
diff --git a/tests/test_with_catch/catch.cpp b/tests/test_with_catch/catch.cpp
index 171d1df626..5bd8b3880e 100644
--- a/tests/test_with_catch/catch.cpp
+++ b/tests/test_with_catch/catch.cpp
@@ -13,63 +13,10 @@ PYBIND11_WARNING_DISABLE_MSVC(4996)
 #endif
 
 #define CATCH_CONFIG_RUNNER
-#define CATCH_CONFIG_DEFAULT_REPORTER "progress"
 #include <catch.hpp>
 
 namespace py = pybind11;
 
-// Simple progress reporter that prints a line per test case.
-namespace {
-
-bool g_printed_python_version = false;
-
-class ProgressReporter : public Catch::CumulativeReporterBase<ProgressReporter> {
-public:
-    using CumulativeReporterBase::CumulativeReporterBase;
-
-    static std::string getDescription() { return "Simple progress reporter (one line per test)"; }
-
-    void testCaseStarting(Catch::TestCaseInfo const &testInfo) override {
-        if (!g_printed_python_version) {
-            g_printed_python_version = true;
-            const char *version = Py_GetVersion();
-            stream << "[ PYTHON   ] " << version << '\n';
-            stream.flush();
-        }
-        stream << "[ RUN      ] " << testInfo.name << '\n';
-        stream.flush();
-        CumulativeReporterBase::testCaseStarting(testInfo);
-    }
-
-    void testCaseEnded(Catch::TestCaseStats const &testCaseStats) override {
-        auto const &info = testCaseStats.testInfo;
-        bool failed = (testCaseStats.totals.assertions.failed > 0);
-        stream << (failed ? "[  FAILED  ] " : "[       OK ] ") << info.name << '\n';
-        stream.flush();
-        CumulativeReporterBase::testCaseEnded(testCaseStats);
-    }
-
-    static std::set<Catch::Verbosity> getSupportedVerbosities() {
-        return {Catch::Verbosity::Normal};
-    }
-
-    void testRunEndedCumulative() override {}
-
-    void noMatchingTestCases(std::string const &spec) override {
-        stream << "[  NO TEST ] no matching test cases for spec: " << spec << '\n';
-        stream.flush();
-    }
-
-    void reportInvalidArguments(std::string const &arg) override {
-        stream << "[   ERROR  ] invalid Catch2 arguments: " << arg << '\n';
-        stream.flush();
-    }
-};
-
-} // namespace
-
-CATCH_REGISTER_REPORTER("progress", ProgressReporter)
-
 int main(int argc, char *argv[]) {
     // Setup for TEST_CASE in test_interpreter.cpp, tagging on a large random number:
     std::string updated_pythonpath("pybind11_test_with_catch_PYTHONPATH_2099743835476552");

From ee5f7d7fee615538b5a2c93d776d747c195694b5 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 09:42:20 -0800
Subject: [PATCH 22/24] Change runner to ubuntu-24.04

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d00ee6d27e..36dcd6363d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -472,7 +472,7 @@ jobs:
   # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
     timeout-minutes: 90
 

From cc385d7005f94bcc261b5115284b2176266d7d9f Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 09:50:14 -0800
Subject: [PATCH 23/24] Use nvhpc-25-11

---
 .github/workflows/ci.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 36dcd6363d..5b4f48548c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -473,7 +473,7 @@ jobs:
   ubuntu-nvhpc7:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-24.04
-    name: "🐍 3 • NVHPC 23.5 • C++17 • x64"
+    name: "🐍 3 • NVHPC 25.11 • C++17 • x64"
     timeout-minutes: 90
 
     env:
@@ -491,7 +491,7 @@ jobs:
       run: |
         sudo apt-get update -y && \
         sudo apt-get install -y cmake environment-modules git python3-dev python3-pip python3-numpy && \
-        sudo apt-get install -y --no-install-recommends nvhpc-23-5 && \
+        sudo apt-get install -y --no-install-recommends nvhpc-25-11 && \
         sudo rm -rf /var/lib/apt/lists/*
         python3 -m pip install --upgrade pip
         python3 -m pip install --upgrade pytest
@@ -502,7 +502,7 @@ jobs:
       shell: bash
       run: |
         source /etc/profile.d/modules.sh
-        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/23.5
+        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/25.11
         cmake -S . -B build -DDOWNLOAD_CATCH=ON \
                             -DCMAKE_CXX_STANDARD=17 \
                             -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)") \
@@ -510,7 +510,7 @@ jobs:
                             -DPYBIND11_TEST_FILTER="test_smart_ptr.cpp"
 
     - name: Build
-      run: cmake --build build -j 2 --verbose
+      run: cmake --build build -j $(nproc) --verbose
 
     - name: Python tests
       run: cmake --build build --target pytest

From a14af7722230c306881ab2df7a122c549d8c2b91 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rgrossekunst@nvidia.com>
Date: Sun, 14 Dec 2025 17:39:58 -0800
Subject: [PATCH 24/24] =?UTF-8?q?Remove=20misleading=207=20from=20job=20na?=
 =?UTF-8?q?me=20(i.e.=20ubuntu-nvhpc7=20=E2=86=92=20ubuntu-nvhpc)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5b4f48548c..c5a200e32e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -470,7 +470,7 @@ jobs:
 
 
   # Testing on Ubuntu + NVHPC (previous PGI) compilers, which seems to require more workarounds
-  ubuntu-nvhpc7:
+  ubuntu-nvhpc:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-24.04
     name: "🐍 3 • NVHPC 25.11 • C++17 • x64"