findAvailablePort in test.dart / service_worker_test.dart is a race condition and likely causes flaky tests #109474

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1. Hixie

   added

   a: tests"flutter test", flutter_test, or one of our tests"flutter test", flutter_test, or one of our tests

   team: flakes

   platform-webWeb applications specificallyWeb applications specifically

   P2Important issues not at the top of the work listImportant issues not at the top of the work list

   on Aug 12, 2022
2. yjbanov commented on Aug 12, 2022

   

   yjbanov

   on Aug 12, 2022

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   Is this where the race is

   flutter/dev/bots/utils.dart

   Line 85 in dce82f7

   Future<int> findAvailablePort() async {

   ?

   What multiple things are racing against each other?
   What would be the best way to find a free port?
3. Hixie commented on Aug 12, 2022

   

   Hixie

   on Aug 12, 2022

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   We could be racing against anything in the OS that happens to open a port at the same time.

   In general the best way to find a port is to ask the OS to allocate you one, and then use it. Often saying "port 0" is the way to do that.
4. flutter-triage-bot

   added

   c: flakeTests that sometimes, but not always, incorrectly passTests that sometimes, but not always, incorrectly pass

   team-webOwned by Web platform teamOwned by Web platform team

   triaged-webTriaged by Web platform teamTriaged by Web platform team

   on Jul 7, 2023
5. chinmaygarde

   removed

   team: flakes

   on Jul 19, 2023
6. mdebbar commented on Oct 19, 2026

   

   mdebbar

   on Oct 19, 2026

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   Fixed in #194419
7. mdebbar

   closed this as completedon Oct 19, 2026
8. github-actions commented on Nov 2, 2026

   

   github-actionsBot

   on Nov 2, 2026 – with GitHub Actions

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   This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.
9. github-actions

   locked as resolved and limited conversation to collaborators on Nov 2, 2026