make producer race test deterministic - #1335
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The producer concurrency regression processes 10,000 jobs and relies on finishing the last one within a fixed deadline. Race-enabled CI can exercise the intended overlap many times and still fail solely because it misses that throughput deadline. Replace the workload with a coordinated three-job scenario that blocks fetches after capacity is calculated. Complete jobs while fetches are pending and read capacity concurrently across removals and additions. This keeps unsafe active-job accounting visible to the race detector. Assert each capacity transition and verify that a queued third job runs after a slot reopens. Run the scenario through both poll-only and notifier producer setups, using the pilot seam so no production-only test signal is needed. Keep reusable test plumbing generic with a pre-fetch pilot hook while the scenario owns its fetch schedule. Use zero-based job indices and single-owner gate cleanup. Stream capacity transitions in order, with cancellation-aware sends, so failures cannot strand the observer. Document the gated sequence so completion during a pending fetch, the retained fetch limit, refill timing, and observer lifetime are explicit.
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Oops thought I sent this comment earlier: @brandur this is still not the easiest test to read, but I do think it retains the coverage of the old test while being fully deterministic. |
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This is a draft alternative to #1248.
The existing race regression test processes 10,000 jobs and relies on the final job starting within a fixed deadline, so race-enabled CI can fail from throughput variance even when the intended concurrency path is exercised.
Replace it with a coordinated three-job scenario that blocks fetches after capacity is calculated. The test completes jobs while fetches are pending, continuously reads capacity across active-job removals and additions, and asserts each capacity transition. A queued third job preserves backlog/refill coverage, and the scenario runs through both poll-only and notifier producer setups.
This guarantees the completion-during-fetch overlap without a wall-clock throughput deadline and keeps unsafe active-job accounting visible to the race detector without adding production-only test instrumentation.