parallel/test-fs-promises-watch-iterator is flaky #60051

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1. gurgunday

   added

   flaky-testIssues and PRs involving tests that fail intermittently in CI.Issues and PRs involving tests that fail intermittently in CI.

   on Sep 28, 2025
2. github-actions

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   macosIssues and PRs related to the macOS platform.Issues and PRs related to the macOS platform.

   on Sep 28, 2025
3. lpinca commented on Sep 28, 2025

   

   lpinca

   on Sep 28, 2025

   Last edited by lpinca

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   I can reproduce the issue on my mac by running the following command:

   python3 tools/test.py --repeat=1000 --timeout=2 test/parallel/test-fs-promises-watch-iterator.js
   

   There seems to be a race condition where some (sometimes all) events are missing. If a small delay is added before writing the files the flakiness goes away

   diff --git a/test/parallel/test-fs-promises-watch-iterator.js b/test/parallel/test-fs-promises-watch-iterator.js
   index 1606bdef422..e73a1af589a 100644
   --- a/test/parallel/test-fs-promises-watch-iterator.js
   +++ b/test/parallel/test-fs-promises-watch-iterator.js
   @@ -34,10 +34,10 @@ class WatchTestCase {
        }
      }
      async writeFiles() {
   +    await setTimeout(common.platformTimeout(100));
        for (const fileName of [...this.files]) {
          await writeFile(this.filePath(fileName), Date.now() + fileName.repeat(1e4));
        }
   -    await setTimeout(common.platformTimeout(100));
      }
    }
    
   

   Anyway, I'm not sure if the above patch invalidates the test or hides an actual bug in the watch/iterator implementation.
4. gurgunday commented on Sep 28, 2025

   

   gurgunday

   on Sep 28, 2025

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   Anyway, I'm not sure if the above patch invalidates the test

   Yeah I thought about moving the timeout up too but had the same concern
5. pipobscure commented on Sep 30, 2025

   

   pipobscure

   on Sep 30, 2025

   Contributor

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   The test is meant to test that multiple file events are all handled when following in rapid succession. The sleep at the beginning is fine. As a matter of fact it should make things more stable as the the initial watcher setup is completed during that. The original test depends on asynchronous functions executing code before the first awai synchronously therefore staring the watcher before writing files.

   So your instinct in moving the sleep up is good and we should do that. It won’t impact the test’s value so long as there is no sleep in between file writes.
6. lpinca

   added a commit that references this issue on Oct 4, 2025

   test: deflake test-fs-promises-watch-iterator

   ...

   dfdbb39
7. nodejs-github-bot

   closed this as completedin #60060on Oct 9, 2025
8. nodejs-github-bot

   added a commit that references this issue on Oct 9, 2025

   test: deflake test-fs-promises-watch-iterator

   ...

   f8a43f6
9. aduh95

   added 2 commits that reference this issue on Oct 31, 2025

   test: deflake test-fs-promises-watch-iterator

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   c88ea78

   test: deflake test-fs-promises-watch-iterator

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10. aduh95

    added a commit that references this issue on Feb 17, 2026

    test: deflake test-fs-promises-watch-iterator

    ...

    1d05b44