Sandbox::https://github.com/flutter/flutter/pull/188288

loic-sharma · 2026-06-21T22:14:09Z

Adds a new debug global, debugPaintFocusBoxes, to visualize the focus tree:

Green box: the primary focus node
Blue boxes: focus nodes that are ancestors of the primary focus node
Cyan boxes: focus nodes that are focusable and traversable
Yellow boxes: focus nodes that are focusable but not traversable
Red boxes: focus nodes that are not focusable

Demo

void main() {
  debugPaintFocusBoxes = true;
  runApp(const CalendarDatePickerApp());
}

Screen.Recording.2026-06-21.at.2.24.06.PM.mov

Pre-launch Checklist

gemini-code-assist

Code Review

This pull request introduces a new debugging flag, debugPaintFocusBoxes, which draws colored borders around Focus widgets to visually indicate their focus state, and adds corresponding unit tests. The review feedback suggests adding missing imports for painting and rendering classes, using triple-slash documentation comments for private members to align with the style guide, and optimizing ListenableBuilder usage by leveraging its child parameter. Additionally, the reviewer recommends using addTearDown in tests to safely reset the debugging flag and avoid test pollution, which also allows for the removal of manual resets.

gemini-code-assist · 2026-06-21T22:15:55Z

+
+    testWidgets('adds a border on each Focus widget if enabled',
+        (WidgetTester tester) async {
+      debugPaintFocusBoxes = true;


To prevent test pollution, use addTearDown to reset debugPaintFocusBoxes to false. This ensures the flag is reset even if the test fails or throws an exception.

Suggested change

debugPaintFocusBoxes = true;

debugPaintFocusBoxes = true;

addTearDown(() => debugPaintFocusBoxes = false);

Unfortunately, using a teardown to cleanup debug globals results in an exception:

The value of a widget debug variable was changed by the test. When the exception was thrown, this was the stack: #0 debugAssertAllWidgetVarsUnset.<anonymous closure> (package:flutter/src/widgets/debug.dart:569:7) #1 debugAssertAllWidgetVarsUnset (package:flutter/src/widgets/debug.dart:572:4) #2 TestWidgetsFlutterBinding._verifyInvariants (package:flutter_test/src/binding.dart:2019:7) #3 AutomatedTestWidgetsFlutterBinding._verifyInvariants (package:flutter_test/src/binding.dart:2525:11) #4 TestWidgetsFlutterBinding._runTestBody (package:flutter_test/src/binding.dart:1974:7)

The pattern these tests use mirrors other debug global tests. Also, AutomatedTestWidgetsFlutterBinding._verifyInvariants strictly enforces that no tests pollute debug globals.

elliette

One optional change, but otherwise LGTM!

elliette · 2026-06-24T17:00:32Z

+  final Widget child;
+
+  Color get _borderColor {
+    if (node.hasPrimaryFocus) {


Consider changing the colors here (and maybe modifying the border - perhaps making it thicker / semi transparent)? These colors match the ones used in the overlay guidelines (see debugPaint, etc) making it hard to distinguish between the two when both are enabled.

Focus boxes only:

Overlay guidelines only:

Overlay guidelines and focus boxes:

I played with using different colors, but I wasn't able to find a set that I liked as much that was also easily distinguishable from the overlay guidelines. I did bump up the thickness and the add some transparency though!

auto-submit · 2026-07-03T03:46:28Z

autosubmit label was removed for flutter/flutter/188288, because The base commit of the PR is older than 7 days and can not be merged. Please merge the latest changes from the main into this branch and resubmit the PR.

…12137) Manual roll Flutter from 6995038d96ef to 91939cc4db78 (48 revisions) Manual roll requested by stuartmorgan@google.com flutter/flutter@6995038...91939cc 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 80ae1deed9ed to 075fbe4778d9 (6 revisions) (flutter/flutter#189067) 2026-07-07 katelovett@google.com Bump customer testing version for new registrants (flutter/flutter#189070) 2026-07-07 engine-flutter-autoroll@skia.org Roll Packages from fc00ceb to 92525f5 (2 revisions) (flutter/flutter#189069) 2026-07-07 47866232+chunhtai@users.noreply.github.com fix android semantics integration test hangs due to postframe callback (flutter/flutter#189043) 2026-07-07 katelovett@google.com Bump goldctl (flutter/flutter#189030) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 71db7c06c5fe to 80ae1deed9ed (2 revisions) (flutter/flutter#189060) 2026-07-07 magder@google.com Collect analytics on AI agent usage (flutter/flutter#187630) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 125a76cc4cf3 to 71db7c06c5fe (4 revisions) (flutter/flutter#189054) 2026-07-07 engine-flutter-autoroll@skia.org Roll Dart SDK from 70577d6f2bba to c648e3429d76 (1 revision) (flutter/flutter#189052) 2026-07-07 vuhoangminh97@gmail.com Fix RenderSliverPadding setter assertion (flutter/flutter#187353) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 2dde156aec3e to 125a76cc4cf3 (3 revisions) (flutter/flutter#189037) 2026-07-07 49402500+fahaddoc@users.noreply.github.com Explain asynchronous causes in the setState() called after dispose() error (flutter/flutter#187294) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 7dccd1e79a5b to 2dde156aec3e (2 revisions) (flutter/flutter#189035) 2026-07-07 116356835+AbdeMohlbi@users.noreply.github.com Add `STRING_CATALOG_GENERATE_SYMBOLS = YES;` (flutter/flutter#188163) 2026-07-07 31859944+LongCatIsLooong@users.noreply.github.com Print warnings on Intel Macs / targeting Intel Macs (flutter/flutter#188835) 2026-07-07 engine-flutter-autoroll@skia.org Roll Dart SDK from 4c03f64b19f6 to 70577d6f2bba (1 revision) (flutter/flutter#189031) 2026-07-07 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from n1Lm2Z4DZkfC3bwj5... to 7RjQJBW3m-3Jl-7jr... (flutter/flutter#189032) 2026-07-06 31859944+LongCatIsLooong@users.noreply.github.com Recommend `OverlayPortal.overlayChildLayoutBuilder` over Target-Follower (flutter/flutter#188894) 2026-07-06 154381524+flutteractionsbot@users.noreply.github.com Sync CHANGELOG.md from stable (flutter/flutter#189025) 2026-07-06 matt.kosarek@canonical.com Rename preferredSize to size and preferredConstraints to constraints in the windowing API (flutter/flutter#189017) 2026-07-06 6655696+guidezpl@users.noreply.github.com Skip locked issues in no-response check (flutter/flutter#188950) 2026-07-06 47866232+chunhtai@users.noreply.github.com Fix potential race condtion in android_semantics_integration_test (flutter/flutter#188830) 2026-07-06 codefu@google.com ci: udpate wait-for-engine-build composite action to cocoon (flutter/flutter#189020) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 2b55eed5500d to 7dccd1e79a5b (3 revisions) (flutter/flutter#189021) 2026-07-06 jesswon@google.com [AGP 9] Update Flutter Template Versions (flutter/flutter#188762) 2026-07-06 126701490+richyo-codes@users.noreply.github.com fix(engine/windows): keep tooltip position rect alive - fix use after free (flutter/flutter#188476) 2026-07-06 bkonyi@google.com [Tool] Fix null check operator crash in currentPackageConfig (flutter/flutter#188454) 2026-07-06 bkonyi@google.com [Tool] Gracefully handle WDAC/AppLocker blocks for impellerc (flutter/flutter#188452) 2026-07-06 bkonyi@google.com [flutter_tools] Throw DaemonException if app fails to start early (flutter/flutter#188921) 2026-07-06 engine-flutter-autoroll@skia.org Roll Dart SDK from ce7a2567eb59 to 4c03f64b19f6 (2 revisions) (flutter/flutter#189015) 2026-07-06 bkonyi@google.com [flutter_tools, engine] Add --disable-service-origin-check option to disable VM service origin checks (flutter/flutter#188745) 2026-07-06 bkonyi@google.com [flutter_tools] Fix test flakiness in widget_preview_detection_test.dart (flutter/flutter#188922) 2026-07-06 137456488+flutter-pub-roller-bot@users.noreply.github.com Roll pub packages (flutter/flutter#189009) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from c0e2b9667d91 to 2b55eed5500d (1 revision) (flutter/flutter#189006) 2026-07-06 engine-flutter-autoroll@skia.org Roll Packages from 2fbe873 to fc00ceb (1 revision) (flutter/flutter#189007) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from b68567542f81 to c0e2b9667d91 (1 revision) (flutter/flutter#189004) 2026-07-06 Rusino@users.noreply.github.com Fixing multiline GetBoxesForRange (flutter/flutter#188803) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from e15ea7a4b927 to b68567542f81 (4 revisions) (flutter/flutter#189000) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 79806692425f to e15ea7a4b927 (2 revisions) (flutter/flutter#188992) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 2826ae6dc649 to 79806692425f (1 revision) (flutter/flutter#188991) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 7f99eee20fd6 to 2826ae6dc649 (1 revision) (flutter/flutter#188990) 2026-07-06 737941+loic-sharma@users.noreply.github.com Add debugPaintFocusBoxes (flutter/flutter#188288) 2026-07-05 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from bkK6BLiZDRnE7AQQj... to n1Lm2Z4DZkfC3bwj5... (flutter/flutter#188989) 2026-07-05 engine-flutter-autoroll@skia.org Roll Skia from 75a4bf6706bd to 7f99eee20fd6 (2 revisions) (flutter/flutter#188988) ...

…lutter#12137) Manual roll Flutter from 6995038d96ef to 91939cc4db78 (48 revisions) Manual roll requested by stuartmorgan@google.com flutter/flutter@6995038...91939cc 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 80ae1deed9ed to 075fbe4778d9 (6 revisions) (flutter/flutter#189067) 2026-07-07 katelovett@google.com Bump customer testing version for new registrants (flutter/flutter#189070) 2026-07-07 engine-flutter-autoroll@skia.org Roll Packages from fc00ceb to 92525f5 (2 revisions) (flutter/flutter#189069) 2026-07-07 47866232+chunhtai@users.noreply.github.com fix android semantics integration test hangs due to postframe callback (flutter/flutter#189043) 2026-07-07 katelovett@google.com Bump goldctl (flutter/flutter#189030) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 71db7c06c5fe to 80ae1deed9ed (2 revisions) (flutter/flutter#189060) 2026-07-07 magder@google.com Collect analytics on AI agent usage (flutter/flutter#187630) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 125a76cc4cf3 to 71db7c06c5fe (4 revisions) (flutter/flutter#189054) 2026-07-07 engine-flutter-autoroll@skia.org Roll Dart SDK from 70577d6f2bba to c648e3429d76 (1 revision) (flutter/flutter#189052) 2026-07-07 vuhoangminh97@gmail.com Fix RenderSliverPadding setter assertion (flutter/flutter#187353) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 2dde156aec3e to 125a76cc4cf3 (3 revisions) (flutter/flutter#189037) 2026-07-07 49402500+fahaddoc@users.noreply.github.com Explain asynchronous causes in the setState() called after dispose() error (flutter/flutter#187294) 2026-07-07 engine-flutter-autoroll@skia.org Roll Skia from 7dccd1e79a5b to 2dde156aec3e (2 revisions) (flutter/flutter#189035) 2026-07-07 116356835+AbdeMohlbi@users.noreply.github.com Add `STRING_CATALOG_GENERATE_SYMBOLS = YES;` (flutter/flutter#188163) 2026-07-07 31859944+LongCatIsLooong@users.noreply.github.com Print warnings on Intel Macs / targeting Intel Macs (flutter/flutter#188835) 2026-07-07 engine-flutter-autoroll@skia.org Roll Dart SDK from 4c03f64b19f6 to 70577d6f2bba (1 revision) (flutter/flutter#189031) 2026-07-07 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from n1Lm2Z4DZkfC3bwj5... to 7RjQJBW3m-3Jl-7jr... (flutter/flutter#189032) 2026-07-06 31859944+LongCatIsLooong@users.noreply.github.com Recommend `OverlayPortal.overlayChildLayoutBuilder` over Target-Follower (flutter/flutter#188894) 2026-07-06 154381524+flutteractionsbot@users.noreply.github.com Sync CHANGELOG.md from stable (flutter/flutter#189025) 2026-07-06 matt.kosarek@canonical.com Rename preferredSize to size and preferredConstraints to constraints in the windowing API (flutter/flutter#189017) 2026-07-06 6655696+guidezpl@users.noreply.github.com Skip locked issues in no-response check (flutter/flutter#188950) 2026-07-06 47866232+chunhtai@users.noreply.github.com Fix potential race condtion in android_semantics_integration_test (flutter/flutter#188830) 2026-07-06 codefu@google.com ci: udpate wait-for-engine-build composite action to cocoon (flutter/flutter#189020) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 2b55eed5500d to 7dccd1e79a5b (3 revisions) (flutter/flutter#189021) 2026-07-06 jesswon@google.com [AGP 9] Update Flutter Template Versions (flutter/flutter#188762) 2026-07-06 126701490+richyo-codes@users.noreply.github.com fix(engine/windows): keep tooltip position rect alive - fix use after free (flutter/flutter#188476) 2026-07-06 bkonyi@google.com [Tool] Fix null check operator crash in currentPackageConfig (flutter/flutter#188454) 2026-07-06 bkonyi@google.com [Tool] Gracefully handle WDAC/AppLocker blocks for impellerc (flutter/flutter#188452) 2026-07-06 bkonyi@google.com [flutter_tools] Throw DaemonException if app fails to start early (flutter/flutter#188921) 2026-07-06 engine-flutter-autoroll@skia.org Roll Dart SDK from ce7a2567eb59 to 4c03f64b19f6 (2 revisions) (flutter/flutter#189015) 2026-07-06 bkonyi@google.com [flutter_tools, engine] Add --disable-service-origin-check option to disable VM service origin checks (flutter/flutter#188745) 2026-07-06 bkonyi@google.com [flutter_tools] Fix test flakiness in widget_preview_detection_test.dart (flutter/flutter#188922) 2026-07-06 137456488+flutter-pub-roller-bot@users.noreply.github.com Roll pub packages (flutter/flutter#189009) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from c0e2b9667d91 to 2b55eed5500d (1 revision) (flutter/flutter#189006) 2026-07-06 engine-flutter-autoroll@skia.org Roll Packages from 2fbe873 to fc00ceb (1 revision) (flutter/flutter#189007) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from b68567542f81 to c0e2b9667d91 (1 revision) (flutter/flutter#189004) 2026-07-06 Rusino@users.noreply.github.com Fixing multiline GetBoxesForRange (flutter/flutter#188803) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from e15ea7a4b927 to b68567542f81 (4 revisions) (flutter/flutter#189000) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 79806692425f to e15ea7a4b927 (2 revisions) (flutter/flutter#188992) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 2826ae6dc649 to 79806692425f (1 revision) (flutter/flutter#188991) 2026-07-06 engine-flutter-autoroll@skia.org Roll Skia from 7f99eee20fd6 to 2826ae6dc649 (1 revision) (flutter/flutter#188990) 2026-07-06 737941+loic-sharma@users.noreply.github.com Add debugPaintFocusBoxes (flutter/flutter#188288) 2026-07-05 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from bkK6BLiZDRnE7AQQj... to n1Lm2Z4DZkfC3bwj5... (flutter/flutter#188989) 2026-07-05 engine-flutter-autoroll@skia.org Roll Skia from 75a4bf6706bd to 7f99eee20fd6 (2 revisions) (flutter/flutter#188988) ...

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Add debugPaintFocusBoxes

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Comment thread packages/flutter/lib/src/widgets/debug.dart Resolved

Comment thread packages/flutter/lib/src/widgets/focus_scope.dart Resolved

Document that debugPaintFocusBoxes modifies the widget tree

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Tweak

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Make border thicker and a little transparent

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Merge branch 'master' into debug_focus

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Add debugPaintFocusBoxes - #188288

Add debugPaintFocusBoxes#188288
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	debugPaintFocusBoxes = true;
	debugPaintFocusBoxes = true;
	addTearDown(() => debugPaintFocusBoxes = false);

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loic-sharma commented Jun 21, 2026

Demo

Pre-launch Checklist

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