Make DropdownMenu generic type non nullable #176711
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It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging. If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix? Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. If you believe this PR qualifies for a test exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!). The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group. |
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I have 2 questions:
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Code Review
This pull request makes the generic type T for DropdownMenu and DropdownMenuFormField non-nullable by adding an extends Object constraint. This is a good change for type safety, as it ensures that the value of a DropdownMenuEntry is always non-nullable within these widgets. The documentation for onSelected has also been updated to be more descriptive and clear, which is a great improvement. The changes are consistent and well-implemented across both dropdown_menu.dart and dropdown_menu_form_field.dart.
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I'm in favor of making this change. import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(
title: 'Flutter Demo',
home: Card(
child: DropdownMenu<String?>(
dropdownMenuEntries: [
DropdownMenuEntry(value: null, label: 'Label'),
DropdownMenuEntry(value: '1', label: '1'),
DropdownMenuEntry(value: '2', label: '2'),
],
),
),
);
}
}
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LGTM 👍 . Also tagged @LongCatIsLooong for review since he wrote the issue.
Is it considered a breaking change?
See https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#1-determine-if-your-change-is-a-breaking-change. It certainly could break customers, but it looks like the customer tests are passing at least. Let's see if it passes Google tests too.
Is this PR text-exempted?
I can't think of any way to test this. Can you request an exemption? See that bot's comment above.
| /// selection was cleared / that no item was chosen. | ||
| /// | ||
| /// Defaults to null. If this callback itself is null, the widget still updates | ||
| /// the text field with the selected label but does not notify the caller. |
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Nit: remove the part after "but" since that sounds obvious and it's unclear who the "caller" is
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Sure, I removed it in Remove extra sentence
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#176753 something to consider before this gets merged. |
Fixes #175090
Pre-launch Checklist
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