SliverSemantics #167300

Renzo-Olivares · 2025-04-16T19:53:34Z

Pre-launch Checklist

I read the [Contributor Guide] and followed the process outlined 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].
I followed the [breaking change policy] and added [Data Driven Fixes] where supported.
All existing and new tests are passing.

Renzo-Olivares · 2025-06-06T17:54:10Z

packages/flutter/test/widgets/sliversemantics_test.dart

+  });
+
+  testWidgets(
+    'does not merge conflicting actions even if one of them is blocked with Semantics widget',


I'm not too sure if the expected explicitChildNodes: true is the way to solve the issues with this test.

For context this test comes from:

flutter/packages/flutter/test/widgets/semantics_test.dart

Lines 1588 to 1622 in 48c6ef2

testWidgets('does not merge conflicting actions even if one of them is blocked', (

WidgetTester tester,

) async {

final UniqueKey key = UniqueKey();

await tester.pumpWidget(

MaterialApp(

home: Semantics(

key: key,

container: true,

child: Column(

children: <Widget>[

Semantics(

blockUserActions: true,

label: 'label1',

onTap: () {},

child: const SizedBox(width: 10, height: 10),

),

Semantics(

label: 'label2',

onTap: () {},

child: const SizedBox(width: 10, height: 10),

),

],

),

),

),

);

final SemanticsNode node = tester.getSemantics(find.byKey(key));

expect(

node,

matchesSemantics(

children: <Matcher>[containsSemantics(label: 'label1'), containsSemantics(label: 'label2')],

),

);

});

In the test above the nodes under Column are not merged, but in this sliver test, the nodes under SliverList are merged, unless I use explicitChildNodes true in the SliverSemantics widget above the SliverList. I debugged and found that the cause for this is because SliverList adds semantics indexes with IndexedSemantics. If we do addSemanticIndexes: false, then this test also passes.

In the original test from semantics_test.dart if I add an IndexedSemantics around each child of the Column then we run into the same issue where the nodes under the Column are merged.

Created an issue #170485 and updated test to use SliverToBoxAdapter -> Column for now.

Renzo-Olivares · 2025-06-06T17:55:34Z

Google testing is failing because there already exists a SliverSemantics, I think I will try to migrate those uses to use the frameworks SliverSemantics.

chunhtai

overall approach LGTM, just some suggestions to make code a bit cleaner

chunhtai · 2025-06-06T18:12:17Z

packages/flutter/lib/src/rendering/object.dart

+/// for their subtree.
+mixin SemanticsAnnotationsMixin on RenderObject {
+  /// Initializes the semantics annotations for this mixin.
+  void initSemanticsAnnotations({


If this is not meant to be developer facing API. I will turn all the parameter to be required just so that one day we add parameter to the list, we won't forget to update all the internal reference

chunhtai · 2025-06-06T18:15:29Z

packages/flutter/lib/src/widgets/basic.dart

+/// A sliver that annotates its subtree with a description of the meaning of
+/// the slivers.
+///
+/// Used by assistive technologies, search engines, and other semantic analysis


can this use template to deduplicate the doc between this and Semantics widget

I think so, but do you think both should point to the same youtube video since the video talks about the Semantics widget. They're essentially used the same way, but it may be confusing to some? What do you think?

yes, I think this is confusing. I think we should exclude the video out of sliver version of doc

chunhtai · 2025-06-06T18:15:53Z

packages/flutter/lib/src/widgets/basic.dart

+///
+/// See also:
+///
+///  * [SemanticsProperties], which contains a complete documentation for each


maybe add a link to Semantics widget

same for the breadcumb in Semantics widget.

chunhtai · 2025-06-06T18:16:39Z

packages/flutter/lib/src/widgets/basic.dart

+  /// to create semantic boundaries that are either writable or not for children.
+  final bool explicitChildNodes;
+
+  /// Whether to replace all child semantics with this node.


most of this can be doc string

chunhtai · 2025-06-06T18:18:24Z

packages/flutter/lib/src/widgets/basic.dart

+
+  /// Contains properties used by assistive technologies to make the application
+  /// more accessible.
+  final SemanticsProperties properties;


can any of these and the Semantics counter part to be factored out into a mixin. Asking this because adding a flag/property in semantics is already cumbersome, would appreciate we don't add another place that needs to be updated...

Good point! I'll look into ways we can do this.

What do you think about this approach? f22a87a (#167300)

A base class used by both Semantics and SliverSemantics called SemanticsBase where SemanticsBase has its own constructor with every field marked as required. This enforces its subclasses to add that field to their constructor whenever a new one is added to SemanticsBase.

In this world, when we add a new field to SemanticsBase and mark it required, an analyzer error will appear pointing us to add the same field to its subclasses Semantics and SliverSemantics.

…sAnnotation

chunhtai

LGTM, would be good if we can make it private, but not blocking the pr merge

chunhtai · 2025-06-11T16:39:22Z

packages/flutter/lib/src/widgets/basic.dart

+///    be enabled using [WidgetsApp.showSemanticsDebugger],
+///    [MaterialApp.showSemanticsDebugger], or [CupertinoApp.showSemanticsDebugger].
+/// {@endtemplate}
+sealed class SemanticsBase extends SingleChildRenderObjectWidget {


Thanks for refactor this out it is a lot less duplicated code now, I wonder if this can be private? not sure whether the api doc still work if we make it private though.

github-actions bot added framework flutter/packages/flutter repository. See also f: labels. f: scrolling Viewports, list views, slivers, etc. labels Apr 16, 2025

Renzo-Olivares force-pushed the sliver-semantics branch from cd37169 to b42e20d Compare May 8, 2025 21:07

github-actions bot added a: accessibility Accessibility, e.g. VoiceOver or TalkBack. (aka a11y) d: api docs Issues with https://api.flutter.dev/ d: examples Sample code and demos labels May 8, 2025

Renzo-Olivares force-pushed the sliver-semantics branch 4 times, most recently from 02769d5 to 7202c32 Compare May 10, 2025 00:32

Renzo-Olivares force-pushed the sliver-semantics branch from 7202c32 to ad7e10d Compare May 19, 2025 20:35

Renzo-Olivares force-pushed the sliver-semantics branch 3 times, most recently from 432ea93 to 88b0c8a Compare June 4, 2025 20:25

Renzo-Olivares force-pushed the sliver-semantics branch from 152fe42 to 172f614 Compare June 6, 2025 17:44

Renzo-Olivares changed the title ~~[WIP] SliverSemantics~~ SliverSemantics Jun 6, 2025

Renzo-Olivares marked this pull request as ready for review June 6, 2025 17:45

Renzo-Olivares force-pushed the sliver-semantics branch from 172f614 to 763928e Compare June 6, 2025 17:46

Renzo-Olivares requested a review from chunhtai June 6, 2025 17:47

Renzo-Olivares commented Jun 6, 2025

View reviewed changes

chunhtai reviewed Jun 6, 2025

View reviewed changes

Renzo-Olivares force-pushed the sliver-semantics branch from 763928e to 820c45d Compare June 9, 2025 21:57

Renzo Olivares added 7 commits June 9, 2025 15:05

make 1-1 Semantics widget equivalent for Slivers

7ab456e

Share code between RenderSliverSemanticsAnnotation and RenderSemantic…

4eaa729

…sAnnotation

update example with new SliverSemantics

8aa2f77

update docs

713d940

fix analyzer

267c0db

fix analyzer

a161b72

fix analyzer

b82398f

Renzo Olivares added 13 commits June 9, 2025 15:05

fix analyzer

da603ea

add tests

03470bd

more tests

12b7475

more tests

bba299a

more tests

31e259f

rename test file

8f3bfaf

add test

d66431c

clean up

8ffbdc0

Add another test

c0fe96f

remove unused import

b4670f4

add test

bcb170a

Create SemanticsBase

f22a87a

Make initSemanticAnnotations required

5587ac5

Renzo-Olivares force-pushed the sliver-semantics branch from 3e881a7 to 5587ac5 Compare June 9, 2025 22:05

Renzo Olivares added 3 commits June 10, 2025 11:24

fix analyzer

4f4c6fb

anaylzer fix

686c6af

fix tests

e772e14

Renzo-Olivares requested a review from chunhtai June 11, 2025 16:26

chunhtai approved these changes Jun 11, 2025

View reviewed changes

Renzo Olivares added 4 commits June 11, 2025 11:14

clean up docs

11a701f

update tests

ab292de

SliverSemantics should have a child sliver

6b91b21

clean up

3dbc341

	testWidgets('does not merge conflicting actions even if one of them is blocked', (
	WidgetTester tester,
	) async {
	final UniqueKey key = UniqueKey();
	await tester.pumpWidget(
	MaterialApp(
	home: Semantics(
	key: key,
	container: true,
	child: Column(
	children: <Widget>[
	Semantics(
	blockUserActions: true,
	label: 'label1',
	onTap: () {},
	child: const SizedBox(width: 10, height: 10),
	),
	Semantics(
	label: 'label2',
	onTap: () {},
	child: const SizedBox(width: 10, height: 10),
	),
	],
	),
	),
	),
	);
	final SemanticsNode node = tester.getSemantics(find.byKey(key));
	expect(
	node,
	matchesSemantics(
	children: <Matcher>[containsSemantics(label: 'label1'), containsSemantics(label: 'label2')],
	),
	);
	});

SliverSemantics #167300

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SliverSemantics #167300

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Renzo-Olivares commented Apr 16, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Renzo-Olivares commented Jun 6, 2025

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chunhtai Jun 6, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Renzo-Olivares commented Apr 16, 2025 •

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chunhtai Jun 6, 2025 •

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