[hamza-flutterdev]

This change gives the default Material 3 primary TabBar indicator a minimum width of 24dp, centered on the selected label, as specified by the Material 3 tabs spec. It adds a regression test for a short tab label. Custom indicators and secondary tabs retain their existing sizing behavior.

Fixes flutter/flutter#194716

Testing

• dart run script/tool/bin/flutter_plugin_tools.dart test --packages=material_ui — passed for all four targets: material_ui, its example, the accessibility assessments app, and gen_defaults.
• flutter test test/tabs_test.dart — passed (204 tests), including the 24dp regression test.
• flutter analyze lib/src/tabs.dart test/tabs_test.dart — no issues found.
• dart format lib/src/tabs.dart test/tabs_test.dart — completed; no formatting changes were needed.

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [material_ui].
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style.
• I updated/added relevant documentation; no public API documentation changes are needed for this internal behavior fix.
• I added a regression test for the change.
• All existing and new tests are passing.

[gemini-code-assist]

Code Review

This pull request introduces a minimum width of 24dp for the Material 3 primary tab indicator when using the default label indicator size. It updates _IndicatorPainter to accept and enforce a minimumIndicatorWidth during painting and repainting checks, and adds a corresponding widget test to verify this behavior. There are no review comments, so no additional feedback is provided.

[fluttergithubbot]

An existing Git SHA, e2cda364044cefe83645595c796a83f37ae8e9a8, was detected, and no actions were taken.

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[elliette]

Thanks for the contribution! You’ve checked boxes in the PR checklist above that are not reflected in this PR, so I’m assuming this is a work in progress and am marking it as a Draft. Please review the checklist, updating the PR as appropriate, and when the state of the PR as posted reflects the checklist please feel free to mark it as ready for review.

[gemini-code-assist]

Code Review

This pull request introduces a minimum width of 24dp for primary tab indicators when using Material 3 with the default label indicator size. It updates the _IndicatorPainter to enforce this minimum width by centering the indicator if its calculated width is smaller than the minimum, and adds a corresponding widget test to verify this behavior. There are no review comments, so no additional feedback is provided.

[hamza-flutterdev]

Hi @elliette, thanks for the guidance. I’ve updated the PR title and description, added the material_ui pending changelog entry and reviewed the checklist. The PR is now ready for review.

The full material_ui test command passed all four targets. The focused tabs_test.dart run passed all 204 tests, including the new regression test and analysis reported no issues.