From 48b5b96d73ebb271def91984dfe14e50528517d7 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Mon, 29 Dec 2025 22:38:21 +0100
Subject: [PATCH 1/4] switch typing from mypy to ty

---
 docs/source/changes.md                        |  4 ++++
 pyproject.toml                                | 20 ++++------------
 tests/__init__.py                             |  2 +-
 tox.ini                                       |  4 ++--
 {{cookiecutter.project_slug}}/pyproject.toml  | 24 ++++++-------------
 .../tests/__init__.py                         |  2 +-
 6 files changed, 20 insertions(+), 36 deletions(-)

diff --git a/docs/source/changes.md b/docs/source/changes.md
index 106f46b..bfcc1fa 100644
--- a/docs/source/changes.md
+++ b/docs/source/changes.md
@@ -3,6 +3,10 @@
 This is a record of all past cookiecutter-pytask-project releases and what went into
 them in reverse chronological order.
 
+## Unreleased
+
+- {pull}`XX` switches typing from mypy to ty.
+
 ## 1.8.0 - 2024-12-24
 
 - {pull}`52` updates the template in many different ways. Better pre-commit hooks,
diff --git a/pyproject.toml b/pyproject.toml
index f44a38b..48da74e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ docs = [
     "sphinxext-opengraph",
 ]
 test = ["pytest", "pytest-cookies", "pytest-cov"]
-typing = ["mypy"]
+typing = ["ty>=0.0.7"]
 
 [project.readme]
 file = "README.md"
@@ -55,21 +55,11 @@ Documentation = "https://cookiecutter-pytask-project.readthedocs.io/en/latest"
 Github = "https://github.com/pytask-dev/cookiecutter-pytask-project"
 Tracker = "https://github.com/pytask-dev/cookiecutter-pytask-project/issues"
 
-[tool.mypy]
-files = ["hooks", "tests"]
-exclude = "{{cookiecutter.project_slug}}"
-check_untyped_defs = true
-disallow_any_generics = true
-disallow_incomplete_defs = true
-disallow_untyped_defs = true
-no_implicit_optional = true
-warn_redundant_casts = true
-warn_unused_ignores = true
+[tool.ty.rules]
+unused-ignore-comment = "error"
 
-[[tool.mypy.overrides]]
-module = "tests.*"
-disallow_untyped_defs = false
-ignore_errors = true
+[tool.ty.terminal]
+error-on-warning = true
 
 [tool.ruff]
 target-version = "py39"
diff --git a/tests/__init__.py b/tests/__init__.py
index 4045499..e24da9d 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -1 +1 @@
-"""This module is necessary to configure mypy's behavior for the tests."""
+"""Mark tests as a package for type checking."""
diff --git a/tox.ini b/tox.ini
index 49f3e59..9e16ed7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,8 +13,8 @@ commands =
     - sphinx-build -n -T -b doctest -d {envtmpdir}/doctrees docs/source docs/build/html
 
 [testenv:typing]
-extras = typing
-commands = mypy
+extras = typing, test
+commands = ty check hooks/ tests/
 
 [testenv:test]
 extras = test
diff --git a/{{cookiecutter.project_slug}}/pyproject.toml b/{{cookiecutter.project_slug}}/pyproject.toml
index adbe51d..68cfa14 100644
--- a/{{cookiecutter.project_slug}}/pyproject.toml
+++ b/{{cookiecutter.project_slug}}/pyproject.toml
@@ -69,10 +69,10 @@ pytest-cov = "*"
 pytest-xdist = "*"
 
 [tool.pixi.feature.typing.tasks]
-typing = "mypy"
+typing = "ty check src/ tests/"
 
 [tool.pixi.feature.typing.dependencies]
-mypy = "*"
+ty = ">=0.0.7"
 
 [tool.pixi.feature.dev.tasks]
 nb = "jupyter lab --no-browser"
@@ -87,21 +87,11 @@ docs = { features = ["docs"], solve-group = "default" }
 repro = { features = [], solve-group = "default" }
 typing = { features = ["typing"], solve-group = "default" }
 
-[tool.mypy]
-files = ["src", "tests"]
-check_untyped_defs = true
-disallow_any_generics = true
-disallow_incomplete_defs = true
-disallow_untyped_defs = true
-no_implicit_optional = true
-warn_redundant_casts = true
-warn_unused_ignores = true
-ignore_missing_imports = true
-
-[[tool.mypy.overrides]]
-module = "tests.*"
-ignore_errors = true
-disallow_untyped_defs = false
+[tool.ty.rules]
+unused-ignore-comment = "error"
+
+[tool.ty.terminal]
+error-on-warning = true
 
 [tool.pytask.ini_options]
 paths = ["src/{{ cookiecutter.project_slug }}"]
diff --git a/{{cookiecutter.project_slug}}/tests/__init__.py b/{{cookiecutter.project_slug}}/tests/__init__.py
index c3dc044..e24da9d 100644
--- a/{{cookiecutter.project_slug}}/tests/__init__.py
+++ b/{{cookiecutter.project_slug}}/tests/__init__.py
@@ -1 +1 @@
-"""Is module is necessary to configure mypy's behavior for the tests."""
+"""Mark tests as a package for type checking."""

From 200e37fea8d85a73a7e6eb052f04636991d8a567 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Mon, 29 Dec 2025 22:38:45 +0100
Subject: [PATCH 2/4] docs: update changelog for typing migration

---
 docs/source/changes.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/source/changes.md b/docs/source/changes.md
index bfcc1fa..ee17f08 100644
--- a/docs/source/changes.md
+++ b/docs/source/changes.md
@@ -5,7 +5,7 @@ them in reverse chronological order.
 
 ## Unreleased
 
-- {pull}`XX` switches typing from mypy to ty.
+- {pull}`71` switches typing from mypy to ty.
 
 ## 1.8.0 - 2024-12-24
 

From cad923e73cf5a75ac7f78f992dcb29603521d42f Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Tue, 30 Dec 2025 09:41:55 +0100
Subject: [PATCH 3/4] Fix.

---
 tests/test_cookie.py | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/tests/test_cookie.py b/tests/test_cookie.py
index ce41702..7fbe345 100644
--- a/tests/test_cookie.py
+++ b/tests/test_cookie.py
@@ -90,20 +90,23 @@ def test_check_pixi_and_run_all_checks(cookies):
         check=True,
     )
 
-    # Install pre-commit.
+    # Install project dependencies.
+    subprocess.run(("pixi", "install"), cwd=result.project_path, check=True)
+
+    # Install prek.
     subprocess.run(
-        ("pixi", "global", "install", "pre-commit"),
+        ("pixi", "global", "install", "prek"),
         cwd=result.project_path,
         check=True,
     )
     # Check linting, but not on the first try since formatters fix stuff.
     subprocess.run(
-        ("pixi", "run", "pre-commit", "run", "--all-files"),
+        ("pixi", "run", "prek", "run", "--all-files"),
         cwd=result.project_path,
         check=False,
     )
     subprocess.run(
-        ("pixi", "run", "pre-commit", "run", "--all-files"),
+        ("pixi", "run", "prek", "run", "--all-files"),
         cwd=result.project_path,
         check=True,
     )

From bb4503992a185b552ce793d21d82f9919effc4d8 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Tue, 30 Dec 2025 09:50:28 +0100
Subject: [PATCH 4/4] Fix.

---
 tests/test_cookie.py                                           | 3 ---
 .../src/{{cookiecutter.project_slug}}/__init__.py              | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/tests/test_cookie.py b/tests/test_cookie.py
index 7fbe345..723cc7f 100644
--- a/tests/test_cookie.py
+++ b/tests/test_cookie.py
@@ -90,9 +90,6 @@ def test_check_pixi_and_run_all_checks(cookies):
         check=True,
     )
 
-    # Install project dependencies.
-    subprocess.run(("pixi", "install"), cwd=result.project_path, check=True)
-
     # Install prek.
     subprocess.run(
         ("pixi", "global", "install", "prek"),
diff --git a/{{cookiecutter.project_slug}}/src/{{cookiecutter.project_slug}}/__init__.py b/{{cookiecutter.project_slug}}/src/{{cookiecutter.project_slug}}/__init__.py
index f2a52c2..75190c8 100644
--- a/{{cookiecutter.project_slug}}/src/{{cookiecutter.project_slug}}/__init__.py
+++ b/{{cookiecutter.project_slug}}/src/{{cookiecutter.project_slug}}/__init__.py
@@ -4,7 +4,7 @@
 # when the project is installed with ``pip install -e .``. Do not put it into version
 # control!
 try:
-    from ._version import version as __version__
+    from ._version import version as __version__  # ty: ignore[unresolved-import]
 except ImportError:
     __version__ = "unknown"