Fixed -> DropdownMenu throws exception when it is in any scrollable l…

[faisalansari0367]

Fixed -> DropdownMenu throws exception when it is in any scrollable list view and scrolls quickly #139871

[flutter-dashboard]

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[faisalansari0367]

I'd appreciate some assistance in writing the necessary tests to cover the changes introduced in this PR.

Could someone with expertise in testing or familiarity with this part of the codebase kindly review and contribute by creating the required tests? Your input will significantly enhance the reliability and robustness of the code.

Thank you in advance for your collaboration!

[navaronbracke]

You could write a widget test that does the following:

• pump a ListView.builder with the WidgetTester; this widget contains a lot of Containers and a dropdown somewhere in the middle
• start a fling gesture with a high enough velocity that scrolls the list fast enough to both create the Dropdown widget state and to make the widget unmount before the post frame callback ran
• dispose of the gesture that you created, at the end of the test
• add an expect(tester.takeException(), isNull); to verify that no exception happened

[faisalansari0367]

You could write a widget test that does the following:

• pump a ListView.builder with the WidgetTester; this widget contains a lot of Containers and a dropdown somewhere in the middle
• start a fling gesture with a high enough velocity that scrolls the list fast enough to both create the Dropdown widget state and to make the widget unmount before the post frame callback ran
• dispose of the gesture that you created, at the end of the test
• add an expect(tester.takeException(), isNull); to verify that no exception happened

Thanks @navaronbracke

I have added the tests for the same.

[QuncCccccc]

Thanks a lot for the contribution! This looks good:) Could you help rebase master to fix the conflicts?

[faisalansari0367]

@QuncCccccc I have merged it with master, Please approve this PR.
Thanks

[QuncCccccc]

LGTM:) Thanks for the contribution!

[MitchellGoodwin]

LGTM! Thank you for putting this together.