From 4115a78d2c76e506c9429ca56307a05182d9ad19 Mon Sep 17 00:00:00 2001
From: LongCatIsLooong <31859944+LongCatIsLooong@users.noreply.github.com>
Date: Mon, 20 Jan 2025 17:46:25 -0800
Subject: [PATCH] Make `PipelineOwner` a `base` class (#161789)

Such that nobody `implements` it. Currently it has private APIs used by
the `RenderObject` class (e.g., the dirty lists). If someone were to
implement a `PipelineOwner` outside of object.dart, they will get a
runtime `noSuchMethod` crash since they won't be able to provide those
private APIs and RenderObjects actually expect those APIs to exist.

Will be slow to update/respond due to extremely spotty internet :(

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there for submitting PRs.
- [ ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ ] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [ ] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
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Fixes] where supported.
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---
 packages/flutter/lib/src/rendering/binding.dart              | 2 +-
 packages/flutter/lib/src/rendering/object.dart               | 2 +-
 packages/flutter/test/rendering/multi_view_binding_test.dart | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/flutter/lib/src/rendering/binding.dart b/packages/flutter/lib/src/rendering/binding.dart
index df810c00bf..c59267961a 100644
--- a/packages/flutter/lib/src/rendering/binding.dart
+++ b/packages/flutter/lib/src/rendering/binding.dart
@@ -827,7 +827,7 @@ class _BindingPipelineManifold extends ChangeNotifier implements PipelineManifol
 }
 
 // A [PipelineOwner] that cannot have a root node.
-class _DefaultRootPipelineOwner extends PipelineOwner {
+final class _DefaultRootPipelineOwner extends PipelineOwner {
   _DefaultRootPipelineOwner() : super(onSemanticsUpdate: _onSemanticsUpdate);
 
   @override
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index ea4a837f0c..5eae165bdf 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -961,7 +961,7 @@ class _LocalSemanticsHandle implements SemanticsHandle {
 /// without tying it to a specific binding implementation. All [PipelineOwner]s
 /// in a given tree must be attached to the same [PipelineManifold]. This
 /// happens automatically during [adoptChild].
-class PipelineOwner with DiagnosticableTreeMixin {
+base class PipelineOwner with DiagnosticableTreeMixin {
   /// Creates a pipeline owner.
   ///
   /// Typically created by the binding (e.g., [RendererBinding]), but can be
diff --git a/packages/flutter/test/rendering/multi_view_binding_test.dart b/packages/flutter/test/rendering/multi_view_binding_test.dart
index 9993ab78b1..c6e5dab6f1 100644
--- a/packages/flutter/test/rendering/multi_view_binding_test.dart
+++ b/packages/flutter/test/rendering/multi_view_binding_test.dart
@@ -200,7 +200,7 @@ class FakeFlutterView extends Fake implements FlutterView {
   }
 }
 
-class PipelineOwnerSpy extends PipelineOwner {
+final class PipelineOwnerSpy extends PipelineOwner {
   @override
   final SemanticsOwnerSpy semanticsOwner = SemanticsOwnerSpy();
 }