i-slint-live-preview: fix the flaky file watcher tests - #13284
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When a watched directory is deleted, the kernel drops its inotify watch on its own. If the reconcile unwatches the directory before notify has processed the deletion event, inotify_rm_watch fails with EINVAL, and the error was reported to the user. Reproduced with the removing_watched_directory_does_not_report_spurious_errors test, which failed 3 times in 700 runs under CPU load.
When the test root is removed while the watcher is alive, the missing files resolve to the nearest existing ancestor, the shared temp directory, and the teardown registers a watch on it. With the kqueue backend on macOS, notify reacts to writes in a watched directory by recursively watching the first unknown entry, so every parallel test creating its root in the temp directory makes the watcher walk arbitrary trees while the test waits for the worker to finish. Use tempfile for the test directories. The field order of the test context drops the watcher before the directory is removed.
tronical
approved these changes
Sep 8, 2026
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refreshing_watch_set_stops_forwarding_old_pathshung on CI, likely macOS-only:the teardown removed the directory while the watcher was alive, so the watcher
fell back to watching the shared temp directory, which is very expensive with
kqueue. Drop the watcher before the directory, which now comes from
tempfile.While stress testing this locally on Linux, a different test,
removing_watched_directory_does_not_report_spurious_errors, failed a fewtimes with an EINVAL from
inotify_rm_watch: the kernel had already droppedthe watch of the deleted directory. Treat that error as transient.