[web] Refactor LazyPath and separate immutable paths from path builders by mdebbar · Pull Request #177686 · flutter/flutter

mdebbar · 2025-10-28T20:21:37Z

CkPath:
- An immutable Path backed by the immutable SkPath.
- Not exposed to Flutter.
CkPathBuilder:
- A path builder backed by SkPathBuilder.
- Not exposed to Flutter.
SkwasmPath:
- Implements both the immutable path interface and the path builder interface.
- Not exposed to Flutter.
LazyPath:
- The only implementation of the mutable ui.Path interface.
- Exposed to Flutter.
- Manages the lifecycles of renderer-specific paths and path builders.

gemini-code-assist

Code Review

This pull request introduces a significant and well-executed refactoring of the path handling logic in the web engine. By separating the mutable path builder from the immutable path object, the new API is cleaner and more robust. The changes are consistently applied across both the CanvasKit and Skwasm backends, including updates to the relevant tests. I've identified a couple of high-severity issues in the LazyPath implementation related to resource management and potential mutation bugs that should be addressed.

eyebrowsoffire

This is looking great so far!

eyebrowsoffire · 2025-10-28T20:39:27Z


  DisposablePathConstructors constructors;
-  DisposablePath Function() initializer;
+  DisposablePathBuilder Function() initializer;


I think you might be able to just remove this completely, since you've simplified the factory constructors.

It's still used by LazyPath.combined().

We may be able to remove it if we introduce a CombinePathsCommand? I'll see if that's doable.

Please look at my attempt to remove initializer here: 9c095eb

I don't think it's an improvement, but let me know what you think.

flutter-dashboard · 2025-12-02T15:44:49Z

This pull request executed golden file tests, but it has not been updated in a while (20+ days). Test results from Gold expire after as many days, so this pull request will need to be updated with a fresh commit in order to get results from Gold.

For more guidance, visit Writing a golden file test for package:flutter.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

Piinks · 2026-02-03T17:17:10Z

Greetings from stale PR triage! 👋
Is this change still on your radar?

Piinks · 2026-03-09T22:08:36Z

Greetings from stale PR triage! 👋
Is this change still on your radar?

mdebbar · 2026-03-10T19:29:02Z

Still on my radar. Will pick it up soon.

…ath builders (flutter/flutter#177686)

flutter/flutter@bf18e39...2fa45e0 2026-04-13 sigurdm@google.com Test that the locked version of dependencies of sdk packages equal the lower bound (flutter/flutter#183395) 2026-04-13 engine-flutter-autoroll@skia.org Roll Skia from 8d35796258a2 to 55ddd6bb8be5 (1 revision) (flutter/flutter#184952) 2026-04-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from tEm4sdcM6twjxQ0w6... to K_2AkZL3Drs6cGE1q... (flutter/flutter#184930) 2026-04-12 engine-flutter-autoroll@skia.org Roll Dart SDK from 77324e51833a to ef28089d6533 (1 revision) (flutter/flutter#184929) 2026-04-12 engine-flutter-autoroll@skia.org Roll Skia from 6942f5774d65 to 8d35796258a2 (2 revisions) (flutter/flutter#184924) 2026-04-11 engine-flutter-autoroll@skia.org Roll Dart SDK from 8fdbf58b58bd to 77324e51833a (1 revision) (flutter/flutter#184921) 2026-04-11 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from lZcRfPoCLnDttrf9P... to tEm4sdcM6twjxQ0w6... (flutter/flutter#184917) 2026-04-11 engine-flutter-autoroll@skia.org Roll Dart SDK from 7128b5b5142c to 8fdbf58b58bd (1 revision) (flutter/flutter#184906) 2026-04-11 engine-flutter-autoroll@skia.org Roll Skia from 8cbf3db1a0db to 6942f5774d65 (1 revision) (flutter/flutter#184911) 2026-04-11 rmolivares@renzo-olivares.dev `SelectableRegion` can dismiss context menu with keyboard shortcuts (flutter/flutter#184788) 2026-04-11 engine-flutter-autoroll@skia.org Roll Skia from a8128c7adc49 to 8cbf3db1a0db (1 revision) (flutter/flutter#184904) 2026-04-10 engine-flutter-autoroll@skia.org Roll Dart SDK from e715805ddbd3 to 7128b5b5142c (3 revisions) (flutter/flutter#184896) 2026-04-10 engine-flutter-autoroll@skia.org Roll Skia from 7c8b85349a9a to a8128c7adc49 (2 revisions) (flutter/flutter#184899) 2026-04-10 mdebbar@google.com [web] Refactor LazyPath and separate immutable paths from path builders (flutter/flutter#177686) 2026-04-10 engine-flutter-autoroll@skia.org Roll Skia from 25b01e5f4ea0 to 7c8b85349a9a (13 revisions) (flutter/flutter#184887) 2026-04-10 mahimasharma0309@gmail.com Reduce boilerplate in FlutterPlatformViewsTest.mm (flutter/flutter#184555) 2026-04-10 matej.knopp@gmail.com [macOS] Add move timer runloop mode to common modes (flutter/flutter#182295) 2026-04-10 engine-flutter-autoroll@skia.org Roll Packages from 1aa892c to c2e3d1f (5 revisions) (flutter/flutter#184886) 2026-04-10 matej.knopp@gmail.com Win32: Prevent mouse leave on WM_SYSKEYUP. (flutter/flutter#184835) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC boetger@google.com,stuartmorgan@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

…rs (flutter#177686) - `CkPath`: - An immutable Path backed by the immutable `SkPath`. - Not exposed to Flutter. - `CkPathBuilder`: - A path builder backed by `SkPathBuilder`. - Not exposed to Flutter. - `SkwasmPath`: - Implements both the immutable path interface and the path builder interface. - Not exposed to Flutter. - `LazyPath`: - The only implementation of the mutable `ui.Path` interface. - Exposed to Flutter. - Manages the lifecycles of renderer-specific paths and path builders.

AbdeMohlbi · 2026-05-19T07:54:30Z

@mdebbar is there a reason why this did not make it to flutter 3.44.0 or was it because the stable was cut before this commit landed ?

…r#11497) flutter/flutter@bf18e39...2fa45e0 2026-04-13 sigurdm@google.com Test that the locked version of dependencies of sdk packages equal the lower bound (flutter/flutter#183395) 2026-04-13 engine-flutter-autoroll@skia.org Roll Skia from 8d35796258a2 to 55ddd6bb8be5 (1 revision) (flutter/flutter#184952) 2026-04-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from tEm4sdcM6twjxQ0w6... to K_2AkZL3Drs6cGE1q... (flutter/flutter#184930) 2026-04-12 engine-flutter-autoroll@skia.org Roll Dart SDK from 77324e51833a to ef28089d6533 (1 revision) (flutter/flutter#184929) 2026-04-12 engine-flutter-autoroll@skia.org Roll Skia from 6942f5774d65 to 8d35796258a2 (2 revisions) (flutter/flutter#184924) 2026-04-11 engine-flutter-autoroll@skia.org Roll Dart SDK from 8fdbf58b58bd to 77324e51833a (1 revision) (flutter/flutter#184921) 2026-04-11 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from lZcRfPoCLnDttrf9P... to tEm4sdcM6twjxQ0w6... (flutter/flutter#184917) 2026-04-11 engine-flutter-autoroll@skia.org Roll Dart SDK from 7128b5b5142c to 8fdbf58b58bd (1 revision) (flutter/flutter#184906) 2026-04-11 engine-flutter-autoroll@skia.org Roll Skia from 8cbf3db1a0db to 6942f5774d65 (1 revision) (flutter/flutter#184911) 2026-04-11 rmolivares@renzo-olivares.dev `SelectableRegion` can dismiss context menu with keyboard shortcuts (flutter/flutter#184788) 2026-04-11 engine-flutter-autoroll@skia.org Roll Skia from a8128c7adc49 to 8cbf3db1a0db (1 revision) (flutter/flutter#184904) 2026-04-10 engine-flutter-autoroll@skia.org Roll Dart SDK from e715805ddbd3 to 7128b5b5142c (3 revisions) (flutter/flutter#184896) 2026-04-10 engine-flutter-autoroll@skia.org Roll Skia from 7c8b85349a9a to a8128c7adc49 (2 revisions) (flutter/flutter#184899) 2026-04-10 mdebbar@google.com [web] Refactor LazyPath and separate immutable paths from path builders (flutter/flutter#177686) 2026-04-10 engine-flutter-autoroll@skia.org Roll Skia from 25b01e5f4ea0 to 7c8b85349a9a (13 revisions) (flutter/flutter#184887) 2026-04-10 mahimasharma0309@gmail.com Reduce boilerplate in FlutterPlatformViewsTest.mm (flutter/flutter#184555) 2026-04-10 matej.knopp@gmail.com [macOS] Add move timer runloop mode to common modes (flutter/flutter#182295) 2026-04-10 engine-flutter-autoroll@skia.org Roll Packages from 1aa892c to c2e3d1f (5 revisions) (flutter/flutter#184886) 2026-04-10 matej.knopp@gmail.com Win32: Prevent mouse leave on WM_SYSKEYUP. (flutter/flutter#184835) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC boetger@google.com,stuartmorgan@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

mdebbar requested a review from eyebrowsoffire October 28, 2025 20:21

github-actions Bot added engine flutter/engine related. See also e: labels. platform-web Web applications specifically labels Oct 28, 2025

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Comment thread engine/src/flutter/lib/web_ui/lib/src/engine/lazy_path.dart

Comment thread engine/src/flutter/lib/web_ui/lib/src/engine/lazy_path.dart

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mdebbar force-pushed the lazy_path_builder branch from a104fb2 to 9c095eb Compare November 11, 2025 19:21

mdebbar mentioned this pull request Nov 18, 2025

12% regression in dynamic_path_tessellation #178395

Open

mdebbar mentioned this pull request Dec 18, 2025

Path rendering crash on Flutter Web (CanvasKit) with animated Trim Paths #179440

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mdebbar force-pushed the lazy_path_builder branch from d21c6f2 to 7adf8c2 Compare March 16, 2026 15:38

mdebbar added the CICD Run CI/CD label Mar 16, 2026

mdebbar added 15 commits April 3, 2026 16:07

[web] Refactor LazyPath and separate immutable paths from path builders

bf44fbc

now let's do skwasm

06cca2b

keep cached builder around

463af6b

some methods don't require builtPath

801e92d

remove unneeded UniqueRefs

522f1a1

copy path

bb900e1

LazyPath.collect vs dispose

1104229

remove initializer

600a488

unused import

26e8b0b

fix skwasm dispose

f30d355

no need for SkwasmObjectWrapper

2b4b435

lints

b6c088e

remove unused class

b82e64b

rename

11b0663

fix skwasm path metrics test

d4e38c0

mdebbar force-pushed the lazy_path_builder branch from 7adf8c2 to d4e38c0 Compare April 3, 2026 20:07

mdebbar dismissed eyebrowsoffire’s stale review via dfdd77f April 9, 2026 19:45

Merge branch 'master' into lazy_path_builder

929b031

github-actions Bot removed the CICD Run CI/CD label Apr 9, 2026

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Merged via the queue into flutter:master with commit 4b768c7 Apr 10, 2026
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Roll Flutter from bf18e3958a05 to 0f84e85fe403 (12 revisions) flutter/packages#11490

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Roll Flutter from bf18e3958a05 to b1876d8b3156 (15 revisions) flutter/packages#11495

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Roll Flutter from bf18e3958a05 to 2fa45e01aa5c (19 revisions) flutter/packages#11497

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