Use the MacOS directory watcher on Windows too.

.github/workflows/watcher.yaml

@@ -54,7 +54,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        sdk: [3.3, dev]
+        sdk: [3.4, dev]
     steps:
       - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3
       - uses: dart-lang/setup-dart@e51d8e571e22473a2ddebf0ef8a2123f0ab2c02c

pkgs/watcher/CHANGELOG.md

@@ -10,7 +10,10 @@
   exhaustion, "Directory watcher closed unexpectedly", much less likely. The old
   implementation which does not use a separate Isolate is available as
   `DirectoryWatcher(path, runInIsolateOnWindows: false)`.
+- `DirectoryWatcher` on Windows: if buffer exhaustion does happen, emit a
+  "modify" event for all know files instead of an exception.
 - Document behavior on Linux if the system watcher limit is hit.
+- Require Dart SDK `^3.4.0`.
 - Bug fix: native `DirectoryWatcher` implementations now consistently handle
   links as files, instead of sometimes reading through them and sometimes
   reporting them as files. The polling `DirectoryWatcher` still reads through
@@ -33,6 +36,8 @@
 - Bug fix: with `DirectoryWatcher` on Windows, new links to directories were
   sometimes incorrectly handled as actual directories. Now they are reported
   as files, matching the behavior of the Linux and MacOS watchers.
+- Bug fix: unify `DirectoryWatcher` implementation on Windows with the MacOS
+  implementation, addressing various race conditions around directory renames.
 - Bug fix: new `DirectoryWatcher` implementation on Linux that fixes various
   issues: tracking failure following subdirectory move, incorrect events when
   there are changes in a recently-moved subdirectory, incorrect events due to

pkgs/watcher/lib/src/directory_watcher.dart

@@ -15,13 +15,11 @@ import 'directory_watcher/windows_resubscribable_watcher.dart';
 ///
 /// On Windows, the underlying SDK `Directory.watch` fails if too many events
 /// are received while Dart is busy, for example during a long-running
-/// synchronous operation. When this happens, some events are dropped.
-/// `DirectoryWatcher` restarts the watch and sends a `FileSystemException` with
-/// the message "Directory watcher closed unexpectedly" on the event stream. The
-/// code using the watcher needs to do additional work to account for the
-/// dropped events, for example by recomputing interesting files from scratch.
-/// By default, the watcher is started in a separate isolate to make this less
-/// likely. Pass `runInIsolateOnWindows = false` to not launch an isolate.
+/// synchronous operation. When this happens, watching is re-established and a
+/// "modify" event is emitted for any file still present that lost tracking, in
+/// case it changed. By default, the watcher is started in a separate isolate to
+/// make this less likely. Pass `runInIsolateOnWindows = false` to not launch an
+/// isolate.
 ///
 /// On Linux, the underlying SDK `Directory.watch` fails if the system limit on
 /// watchers has been reached. If this happens the SDK exception is thrown, it

pkgs/watcher/lib/src/directory_watcher/directory_list.dart

@@ -7,8 +7,6 @@ import 'dart:io';
 
 import 'package:path/path.dart' as p;
 
-import '../utils.dart';
-
 extension DirectoryRobustRecursiveListing on Directory {
   /// Lists the given directory recursively ignoring not-found or access errors.
   ///
@@ -233,3 +231,18 @@ const _errorInvalidName = 123;
 const _errorBadPathName = 161;
 const _errorAlreadyExists = 183;
 const _errorFilenameExedRange = 206;
+
+extension IgnoringError<T> on Stream<T> {
+  /// Ignore all errors of type [E] emitted by the given stream.
+  ///
+  /// Everything else gets forwarded through as-is.
+  Stream<T> ignoring<E>() {
+    return transform(StreamTransformer<T, T>.fromHandlers(
+      handleError: (error, st, sink) {
+        if (error is! E) {
+          sink.addError(error, st);
+        }
+      },
+    ));
+  }
+}

pkgs/watcher/lib/src/directory_watcher/macos/event_tree.dart → pkgs/watcher/lib/src/directory_watcher/event_tree.dart

@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import '../../unix_paths.dart';
+import '../paths.dart';
 
 /// Tree of event paths relative to the watched path.
 ///

pkgs/watcher/lib/src/directory_watcher/linux/native_watch.dart

@@ -6,8 +6,9 @@ import 'dart:async';
 import 'dart:io';
 
 import '../../event.dart';
-import '../../unix_paths.dart';
-import '../../utils.dart';
+import '../../event_batching.dart';
+import '../../paths.dart';
+import '../../testing.dart';
 
 /// Watches a directory with the native Linux watcher.
 ///
@@ -88,7 +89,7 @@ class NativeWatch {
     logForTesting?.call('NativeWatch(),$watchedDirectory');
     _subscription = watchedDirectory
         .watch()
-        .batchAndConvertEvents()
+        .batchNearbyMicrotasksAndConvertEvents()
         .listen(_onData, onError: _onError);
   }
 

pkgs/watcher/lib/src/directory_watcher/linux/watch_tree.dart

@@ -5,8 +5,8 @@
 import 'dart:io';
 
 import '../../event.dart';
-import '../../unix_paths.dart';
-import '../../utils.dart';
+import '../../paths.dart';
+import '../../testing.dart';
 import '../../watch_event.dart';
 import 'native_watch.dart';
 

pkgs/watcher/lib/src/directory_watcher/linux/watch_tree_root.dart

@@ -4,8 +4,8 @@
 
 import 'dart:async';
 
-import '../../unix_paths.dart';
-import '../../utils.dart';
+import '../../paths.dart';
+import '../../testing.dart';
 import '../../watch_event.dart';
 import 'watch_tree.dart';
 

pkgs/watcher/lib/src/directory_watcher/macos/directory_tree.dart

@@ -4,12 +4,12 @@
 
 import 'dart:io';
 
-import '../../unix_paths.dart';
-import '../../utils.dart';
+import '../../paths.dart';
+import '../../testing.dart';
 import '../../watch_event.dart';
-import 'event_tree.dart';
+import '../event_tree.dart';
 
-/// MacOS directory tree.
+/// MacOS or Windows directory tree.
 ///
 /// Tracks state for a single directory and maintains child [DirectoryTree]
 /// instances for subdirectories.