Add a "pub workspace" to the root of the engine repository (flutter#53539)

... and use it in `engine_tool` to prove everything is working, i.e. on CI and elsewhere.

Partial work towards flutter/flutter#147883.
Supersedes and closes flutter#51782 (which was a prototype).

See also:
- https://flutter.dev/go/pub-workspace, the design doc on the feature.
- dart-lang/pub-dev#7762, an example PR.

I'll probably end up moving the inline docs in `pubspec.yaml` to a `docs/*.md` once that's a thing.

Author: matanlurey

ci/licenses_golden/excluded_files

@@ -12,6 +12,7 @@
 ../../../flutter/.ci.yaml
 ../../../flutter/.clang-format
 ../../../flutter/.clang-tidy
+../../../flutter/.dart_tool
 ../../../flutter/.git
 ../../../flutter/.gitattributes
 ../../../flutter/.github
@@ -252,6 +253,8 @@
 ../../../flutter/lib/web_ui/pubspec.yaml
 ../../../flutter/lib/web_ui/test
 ../../../flutter/prebuilts
+../../../flutter/pubspec.lock
+../../../flutter/pubspec.yaml
 ../../../flutter/runtime/dart_isolate_unittests.cc
 ../../../flutter/runtime/dart_lifecycle_unittests.cc
 ../../../flutter/runtime/dart_plugin_registrant_unittests.cc

lib/ui/channel_buffers.dart

@@ -400,6 +400,8 @@ class ChannelBuffers {
   @Native<Void Function(Handle, Bool)>(symbol: 'PlatformConfigurationNativeApi::SendChannelUpdate')
   external static void _sendChannelUpdate(String name, bool listening);
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   void sendChannelUpdate(String name, {required bool listening}) => _sendChannelUpdate(name, listening);
 
   /// Deprecated. Migrate to [setListener] instead.

lib/ui/compositing.dart

@@ -246,6 +246,8 @@ class ShaderMaskEngineLayer extends _EngineLayerWrapper {
 /// This does not apply when using the `dart:ui` API directly, without using the
 /// Flutter framework bindings, `flutter_test` framework, et al.
 abstract class SceneBuilder {
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   factory SceneBuilder() = _NativeSceneBuilder;
 
   /// Pushes a transform operation onto the operation stack.

lib/ui/experiments/scene.dart

@@ -50,24 +50,34 @@ base class SceneNode extends NativeFieldWrapperClass1 {
     return result;
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static SceneNodeValue fromTransform(Float64List matrix4) {
     final SceneNode sceneNode = SceneNode._create();
     sceneNode._initFromTransform(matrix4);
     return SceneNodeValue.fromValue(sceneNode);
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   void addChild(SceneNode sceneNode) {
     _addChild(sceneNode);
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   void setTransform(Float64List matrix4) {
     _setTransform(matrix4);
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   void setAnimationState(String animationName, bool playing, bool loop, double weight, double timeScale) {
     _setAnimationState(animationName, playing, loop, weight, timeScale);
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   void seekAnimation(String animationName, double time) {
     _seekAnimation(animationName, time);
   }
@@ -126,32 +136,45 @@ base class SceneNode extends NativeFieldWrapperClass1 {
 
   /// Returns a fresh instance of [SceneShader].
   SceneShader sceneShader() => SceneShader._(this, debugName: _debugName);
+
 }
 
+// TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+// ignore: public_member_api_docs
 class SceneNodeValue {
   SceneNodeValue._(this._future, this._value) {
     _future?.then((SceneNode result) => _value = result);
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static SceneNodeValue fromFuture(Future<SceneNode> future) {
     return SceneNodeValue._(future, null);
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static SceneNodeValue fromValue(SceneNode value) {
     return SceneNodeValue._(null, value);
   }
 
   final Future<SceneNode>? _future;
   SceneNode? _value;
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   bool get isComplete {
     return _value != null;
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   Future<SceneNode>? get future {
     return _future;
   }
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   SceneNode? get value {
     return _value;
   }
@@ -186,6 +209,8 @@ base class SceneShader extends Shader {
   // ignore: unused_field
   final String? _debugName;
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   void setCameraTransform(Float64List matrix4) {
     _setCameraTransform(matrix4);
   }

lib/ui/key.dart

@@ -16,6 +16,8 @@ enum KeyEventType {
   /// The key is held, causing a repeated key input.
   repeat;
 
+    // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   String get label {
     return switch (this) {
       down => 'Key Down',
@@ -46,6 +48,8 @@ enum KeyEventDeviceType {
   /// The device is a device connected to an HDMI bus.
   hdmi;
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   String get label {
     return switch (this) {
       keyboard => 'Keyboard',

lib/ui/painting.dart

@@ -2598,6 +2598,8 @@ base class _NativeEngineLayer extends NativeFieldWrapperClass1 implements Engine
 /// Paths can be drawn on canvases using [Canvas.drawPath], and can
 /// used to create clip regions using [Canvas.clipPath].
 abstract class Path {
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   factory Path() = _NativePath;
 
   /// Creates a copy of another [Path].

lib/ui/platform_dispatcher.dart

@@ -2195,6 +2195,8 @@ class ViewConstraints {
 /// [DisplayFeatureState.postureHalfOpened]. For [DisplayFeatureType.cutout],
 /// the state is not used and has the [DisplayFeatureState.unknown] value.
 class DisplayFeature {
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   const DisplayFeature({
     required this.bounds,
     required this.type,

lib/ui/semantics.dart

@@ -281,8 +281,12 @@ class SemanticsAction {
     _kFocusIndex: focus,
   };
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static List<SemanticsAction> get values => _kActionById.values.toList(growable: false);
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static SemanticsAction? fromIndex(int index) => _kActionById[index];
 
   @override
@@ -635,8 +639,12 @@ class SemanticsFlag {
     _kIsExpandedIndex: isExpanded,
   };
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static List<SemanticsFlag> get values => _kFlagById.values.toList(growable: false);
 
+  // TODO(matanlurey): have original authors document; see https://github.com/flutter/flutter/issues/151917.
+  // ignore: public_member_api_docs
   static SemanticsFlag? fromIndex(int index) => _kFlagById[index];
 
   @override

pubspec.yaml

@@ -0,0 +1,173 @@
+# This file represents a "workspace" that applies to the whole repository.
+#
+# See <https://flutter.dev/go/pub-workspace> for details.
+#
+# The `flutter/engine` repository is a quasi-monorepo, with multiple Dart tools
+# and packages that are all interdependent. Third party dependencies are managed
+# by the `DEPS` file in the root of the repository, and are synced to either the
+# `third_party` (i.e. `//flutter/third_party`) or `../third_party` (i.e.
+# `//third_party`) directories by `gclient sync`.
+#
+# Every dependency declared here are dependencies used by _one or more_ of the
+# packages in the repository (though there is no enforcement of this). This file
+# then generates a `.dart_tool/package_config.json` file that is used by the
+# rest of the repository to resolve dependencies.
+#
+# ==============================================================================
+# WORKFLOWS
+# ==============================================================================
+#
+# ------------------------------------------------------------------------------
+# (1) ADDING A NEW DEPENDENCY
+# ------------------------------------------------------------------------------
+# Dependencies need to be added either via the DEPS file, or by checking if they
+# are available in the vendored Dart SDK (see notes below on library locations).
+# If dependencies are available, see (4) for how to add dependencies to a package in the workspace.
+#
+# ------------------------------------------------------------------------------
+# (2) CREATING A NEW PACKAGE
+# ------------------------------------------------------------------------------
+# If creating a package, say in ./tools or ./tools/pkg, ensure the following
+# header in its respective `pubspec.yaml`:
+# ```
+# # We don't publish packages to pub.dev from the engine repository.
+# publish_to: none
+#
+# # Required for workspace support.
+# environment:
+#   sdk: ^3.5.0-294.0.dev
+#
+# # This package is managed as part of the engine workspace.
+# resolution: workspace
+# ```
+#
+# See (4) for how to add dependencies to a package in the workspace.
+#
+# ------------------------------------------------------------------------------
+# (3) MIGRATING A NON-WORKSPACE PACKAGE TO USING THE WORKSPACE
+# ------------------------------------------------------------------------------
+# Many packages in this repo are still using a pre-workspace style pubspec.yaml,
+# either with manually declared `dependency_overrides` (much of ./tools) or by
+# using pub (./web_sdk, ./lib/web_ui). To migrate a package to the workspace:
+#
+# A. Add the `resolution: workspace` field to the pubspec.yaml.
+# B. Update the minimum SDK version to at least `^3.5.0-294.0.dev`.
+# C. Add the package to the `workspace` field in this file.
+# D. Ensure every dependency in the package is added to the `dependencies` field
+#    in this file, following instructions in (4).
+#
+# Once `dart pub get` is run on the workspace, the package will be resolved as
+# part of the workspace, and the `dependency_overrides` in this file will be
+# applied to the package.
+#
+# ------------------------------------------------------------------------------
+# (4) ADDING DEPENDENCIES TO A PACKAGE IN THIS WORKSPACE
+# ------------------------------------------------------------------------------
+# When adding a dependency to a package in the workspace, add the dependency to
+# the `dependencies` field in this file. If the dependency is located within
+# the repository, use the `path` field to point to the package.
+#
+# If the dependency is a third party package, add it to the
+# `dependency_overrides` field in this file. The `any` version constraint is
+# used to indicate that the version of the package is not important, as it is
+# managed by the `DEPS` file.
+
+name: _engine_workspace
+
+# Required for workspace support.
+environment:
+  sdk: ^3.5.0-294.0.dev
+
+# Declare all packages that are part of the workspace.
+workspace:
+  - tools/engine_tool
+
+# Declare all dependencies that are used by one or more packages.
+#
+# A few notes:
+# 1. There is no distinction between "dependencies" and "dev_dependencies";
+#    those notions are for *publishing* packages, not for managing a workspace.
+#    Specific packages in the workspace itself will declare whether they are
+#    dependencies or dev_dependencies, but here it is a union of both.
+#
+# 2. The `any` version constraint is used to indicate that the version of the
+#    package is not important, as it is managed by the `DEPS` file. In other
+#    words, "if the test pass, ship it".
+#
+# While not enforced by tooling, try to keep this list in alphabetical order.
+# TODO(matanlurey): https://dart.dev/tools/linter-rules/sort_pub_dependencies.
+dependencies:
+  args: any
+  async_helper: any
+  expect: any
+  file: any
+  logging: any
+  meta: any
+  path: any
+  platform: any
+  process_runner: any
+  smith: any
+
+# Instructs pub on how to resolve the dependencies that are part of "DEPS".
+#
+# For historic reasons, there are ~3 or so places packages might be located:
+#
+# - `./third_party/pkg/{name}`: for packages vended directly as part of "DEPS".
+#    Usually these are Flutter engine specific packages, i.e. they did not exist
+#    in the Dart vended SDK (the other options below). Typically these originate
+#    from pub (https://pub.dev) and are mirrored into a Google Git repository:
+#    <https://flutter.googlesource.com/>.
+#
+# - `./third_party/dart/pkg/{name}`: for packages that lives *in* the Dart SDK,
+#    which is in turn vendored into the Flutter engine repository. You can see
+#    a full list of available packages here:
+#    <https://github.com/dart-lang/sdk/tree/main/pkg>.
+#
+# - `./third_party/dart/third_party/pkg/{name}`: for packages that are vendored
+#    into the Dart SDK from pub.dev. These are often first-party packages from
+#    the Dart team, but not part of the Dart SDK itself. You can see a full list
+#    of available packages here:
+#    <https://github.com/dart-lang/sdk/blob/main/DEPS>.
+dependency_overrides:
+  args:
+    path: ./third_party/dart/third_party/pkg/args
+  async:
+    path: ./third_party/dart/third_party/pkg/async
+  async_helper:
+    path: ./third_party/dart/pkg/async_helper
+  collection:
+    path: ./third_party/dart/third_party/pkg/collection
+  engine_build_configs:
+    path: ./tools/pkg/engine_build_configs
+  engine_repo_tools:
+    path: ./tools/pkg/engine_repo_tools
+  expect:
+    path: ./third_party/dart/pkg/expect
+  file:
+    path: ./third_party/dart/third_party/pkg/file/packages/file
+  litetest:
+    path: ./testing/litetest
+  logging:
+    path: ./third_party/dart/third_party/pkg/logging
+  meta:
+    path: ./third_party/dart/pkg/meta
+  path:
+    path: ./third_party/dart/third_party/pkg/path
+  platform:
+    path: ./third_party/pkg/platform
+  process:
+    path: ./third_party/pkg/process
+  process_fakes:
+    path: ./tools/pkg/process_fakes
+  process_runner:
+    path: ./third_party/pkg/process_runner
+  smith:
+    path: ./third_party/dart/pkg/smith
+  source_span:
+    path: ./third_party/dart/third_party/pkg/source_span
+  string_scanner:
+    path: ./third_party/dart/third_party/pkg/string_scanner
+  term_glyph:
+    path: ./third_party/dart/third_party/pkg/term_glyph
+  yaml:
+    path: ./third_party/dart/third_party/pkg/yaml

tools/clang_tidy/test/header_filter_regex_test.dart

@@ -36,6 +36,7 @@ void main() {
   test('contains every root directory in the regex', () {
     // These are a list of directories that should _not_ be included.
     const Set<String> intentionallyOmitted = <String>{
+      '.dart_tool',
       '.git',
       '.github',
       'build_overrides',