[Material] update hourFormat to use Dart 3 switch expression by Enderjua · Pull Request #181041 · flutter/flutter

Enderjua · 2026-01-15T19:14:34Z

While I was looking through time.dart, I noticed that hourFormat was still using the old switch-case style with a lot of boilerplate. Since we are moving towards Dart 3 patterns, I thought it'd be a good idea to swap this out for a switch expression. It's much cleaner now and handles the TimeOfDayFormat mapping in just a few lines.

I also realized there weren't any direct tests for this specific function (it was mostly covered by larger integration tests), so I added a small test group in time_test.dart to make sure every enum value maps to the right HourFormat correctly.

This is a trivial internal refactor and does not fix a specific bug report, so no issue is linked.

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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 will sign it once the bot prompts me)
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.
All existing and new tests are passing.

google-cla · 2026-01-15T19:14:40Z

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gemini-code-assist

Code Review

This pull request is a great improvement. It refactors the hourFormat function to use a more modern and concise Dart 3 switch expression, and importantly, adds previously missing unit tests for this logic. The changes improve code quality and maintainability. My feedback includes a couple of suggestions to make the new tests even more robust and easier to debug by adopting a data-driven approach.

gemini-code-assist · 2026-01-15T19:16:05Z

packages/flutter/test/material/time_test.dart

+      expect(hourFormat(of: TimeOfDayFormat.h_colon_mm_space_a), HourFormat.h);
+      expect(hourFormat(of: TimeOfDayFormat.a_space_h_colon_mm), HourFormat.h);


To improve maintainability and debugging, consider refactoring this test to be data-driven. Iterating over a list of test cases makes it easier to add new formats in the future and provides more specific failure messages if a test fails.

This aligns with the 'Writing Effective Tests' guide, which emphasizes that it should be easy to debug a failing test.

const formats = <TimeOfDayFormat>[ TimeOfDayFormat.h_colon_mm_space_a, TimeOfDayFormat.a_space_h_colon_mm, ]; for (final format in formats) { expect(hourFormat(of: format), HourFormat.h, reason: 'for $format'); }

packages/flutter/test/material/time_test.dart

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Enderjua · 2026-01-15T19:44:58Z

@google-cla I have just signed the CLA.

…rmat

victorsanni

Thanks for the PR.

huycozy

Overall, LGTM. Thank you for improving this!
(I don't see this was linked to any issues, though.)

Enderjua · 2026-01-22T00:59:35Z

hello! thanks for the review @huycozy

to clarify the missing issue link, this PR was intended as a standalone refactor to modernize the hourFormat logic using Dart 3 switch expressions. since it is minor improvement to maintainability rather than a bug fix or a new feature, I didnt open a separate issue for it

flutter/flutter#181041)

Roll Flutter from 48c2475 to bfc9041eb118 (173 revisions) flutter/flutter@48c2475...bfc9041 2026-01-23 [email protected] No longer exiting the application when the RegularWindow is destroyed + resolving the window created promise after runWidget (flutter/flutter#181339) 2026-01-23 [email protected] Remove unnecessary Material import from dialog_test.dart (flutter/flutter#181249) 2026-01-23 [email protected] Roll Skia from 8e516fe6828f to db10db8bd55f (1 revision) (flutter/flutter#181379) 2026-01-23 [email protected] Reset TextFormField to initial value after state change (flutter/flutter#181199) 2026-01-23 [email protected] Roll Dart SDK from 980b2b41d36e to e82d7ad1855e (1 revision) (flutter/flutter#181375) 2026-01-23 [email protected] Roll Skia from 3e86f377d300 to 8e516fe6828f (4 revisions) (flutter/flutter#181370) 2026-01-23 [email protected] Remove unnecessary Material import from sliver_visibility_test (flutter/flutter#181248) 2026-01-23 [email protected] Add bottom navigation bar item semantics label (flutter/flutter#180577) 2026-01-23 [email protected] Make topGap not required for CupertinoSheetTransition (flutter/flutter#181269) 2026-01-23 [email protected] Roll Fuchsia Linux SDK from b4cLyhuxciUC-4zCJ... to n7NohL9DPpEuPjNt9... (flutter/flutter#181365) 2026-01-23 [email protected] Roll Dart SDK from 806f04638561 to 980b2b41d36e (1 revision) (flutter/flutter#181364) 2026-01-23 [email protected] Reland hybrid views test (flutter/flutter#181336) 2026-01-23 [email protected] Revert DropdownMenu non-nullable breaking change (flutter/flutter#181074) 2026-01-23 [email protected] Fix leaks in `flutter_test` tests (flutter/flutter#180879) 2026-01-23 [email protected] Re-enable fragment_shader_tests.dart 'Shader Compiler appropriately pads vec3 uniform arrays' test on Vulkan (flutter/flutter#181292) 2026-01-23 [email protected] [ Tool ] Fix `update-packages` failing due to mismatched dependencies between flutter_tools and the framework (flutter/flutter#181335) 2026-01-23 [email protected] [Impeller] Make dynamically created shader metadata for runtime effects consistent with metadata for built-in shaders (flutter/flutter#181201) 2026-01-23 [email protected] Broaden the applicability of `Color` fix_data rules from flutter/painting.dart (flutter/flutter#181093) 2026-01-23 [email protected] Fixes macOS App.framework not being codesigned or find framework (flutter/flutter#181348) 2026-01-22 [email protected] Roll Fuchsia GN SDK from NAEC5tfgSl8g94nwp... to JLBh4Z9PKsjIJcqDU... (flutter/flutter#181139) 2026-01-22 [email protected] Roll Dart SDK from ab4640ea82e9 to 806f04638561 (2 revisions) (flutter/flutter#181347) 2026-01-22 [email protected] Add ExpansibleController.toggle method. (flutter/flutter#181320) 2026-01-22 [email protected] Fixes Typo in codebase (flutter/flutter#181256) 2026-01-22 [email protected] Roll Skia from 4766615bcc96 to 3e86f377d300 (3 revisions) (flutter/flutter#181346) 2026-01-22 [email protected] Make sure that a Hero doesn't crash in 0x0 environment (flutter/flutter#180954) 2026-01-22 [email protected] Reland "Fix capitalization of the path to FlutterWindowControllerTest.mm in the macOS platform build script" (flutter/flutter#181200) 2026-01-22 [email protected] Roll Skia from 6e9746be8c4a to 4766615bcc96 (3 revisions) (flutter/flutter#181331) 2026-01-22 [email protected] Fix remove material import textfield (flutter/flutter#181254) 2026-01-22 [email protected] Add FlutterFramework as an Xcode SwiftPM local package override (flutter/flutter#179512) 2026-01-22 [email protected] Roll Dart SDK from 7bd4c68b625c to ab4640ea82e9 (1 revision) (flutter/flutter#181324) 2026-01-22 [email protected] Roll Packages from d80c60e to 9010299 (9 revisions) (flutter/flutter#181323) 2026-01-22 [email protected] Roll Dart SDK from 2d53a77adc5d to 7bd4c68b625c (2 revisions) (flutter/flutter#181316) 2026-01-22 [email protected] Roll Skia from 3f6949bc5780 to 6e9746be8c4a (2 revisions) (flutter/flutter#181311) 2026-01-22 [email protected] Roll Skia from ef6efc358b4a to 3f6949bc5780 (2 revisions) (flutter/flutter#181307) 2026-01-22 [email protected] Roll Dart SDK from 5d7c8faf2e41 to 2d53a77adc5d (1 revision) (flutter/flutter#181305) 2026-01-22 [email protected] [Material] update hourFormat to use Dart 3 switch expression (flutter/flutter#181041) 2026-01-22 [email protected] Use null-aware elements in cupertino/nav_bar.dart (flutter/flutter#181237) 2026-01-22 [email protected] Roll Fuchsia Linux SDK from b2KIEXVAlEqImQ9VO... to b4cLyhuxciUC-4zCJ... (flutter/flutter#181297) 2026-01-22 [email protected] Roll pub packages (flutter/flutter#181295) 2026-01-22 [email protected] Enables fragment shader test for impeller (fixes mat2 on vulkan) (flutter/flutter#181013) 2026-01-21 [email protected] Roll Dart SDK from 366200db1aa1 to 5d7c8faf2e41 (4 revisions) (flutter/flutter#181290) 2026-01-21 [email protected] Roll Skia from b5ec89e31f59 to ef6efc358b4a (19 revisions) (flutter/flutter#181289) 2026-01-21 [email protected] fix description for semantics finders (flutter/flutter#181214) 2026-01-21 [email protected] Make sure that an Icon doesn't crash in 0x0 environment (flutter/flutter#181021) 2026-01-21 [email protected] Make sure that a GridPaper doesn't crash in 0x0 environment (flutter/flutter#180906) 2026-01-21 [email protected] Bring Linux coverage out of bringup (flutter/flutter#181280) ...

…sions (#181356) Following up on #181041, I took another look at `time_picker.dart` for any remaining switch statements that could be modernized. I found that `_timeSelectorSeparatorValue` and the `height` calculation in `_TimeSelectorSeparator` were great candidates. By using logical OR patterns and inlining the assignments, I was able to convert them into clean switch expressions. The logic remains exactly the same, but the boilerplate is gone. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. (I will sign it once the bot prompts me) - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] All existing and new tests are passing. [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

…#181041) While I was looking through `time.dart`, I noticed that `hourFormat` was still using the old switch-case style with a lot of boilerplate. Since we are moving towards Dart 3 patterns, I thought it'd be a good idea to swap this out for a switch expression. It's much cleaner now and handles the `TimeOfDayFormat` mapping in just a few lines. I also realized there weren't any direct tests for this specific function (it was mostly covered by larger integration tests), so I added a small test group in `time_test.dart` to make sure every enum value maps to the right `HourFormat` correctly. This is a trivial internal refactor and does not fix a specific bug report, so no issue is linked. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. (I will sign it once the bot prompts me) - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] All existing and new tests are passing. [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md --------- Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

…sions (flutter#181356) Following up on flutter#181041, I took another look at `time_picker.dart` for any remaining switch statements that could be modernized. I found that `_timeSelectorSeparatorValue` and the `height` calculation in `_TimeSelectorSeparator` were great candidates. By using logical OR patterns and inlining the assignments, I was able to convert them into clean switch expressions. The logic remains exactly the same, but the boilerplate is gone. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. (I will sign it once the bot prompts me) - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] All existing and new tests are passing. [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

[Material] update hourFormat to use Dart 3 switch expression

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Merge remote-tracking branch 'upstream/master' into modernize-hour-fo…

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Enderjua force-pushed the modernize-hour-format branch from 6702c59 to e8be69d Compare January 16, 2026 00:24

test: implement data-driven tests and fix linting issues

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Enderjua force-pushed the modernize-hour-format branch from e8be69d to 388bbff Compare January 16, 2026 00:37

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Merge branch 'master' into modernize-hour-format

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Merge branch 'master' into modernize-hour-format

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Merge branch 'master' into modernize-hour-format

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Merge branch 'master' into modernize-hour-format

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Merge branch 'master' into modernize-hour-format

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[Material] modernize time picker components with Dart 3 switch expressions #181356

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		expect(hourFormat(of: TimeOfDayFormat.h_colon_mm_space_a), HourFormat.h);
		expect(hourFormat(of: TimeOfDayFormat.a_space_h_colon_mm), HourFormat.h);

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