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turbo-tasks-backend: remove racy ungated collectibles_outdated_dependency test - #100377
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lukesandberg merged 2 commits intoOct 20, 2026
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âĶency test State invalidates its readers one by one, so the collector could re-execute and read the still-clean source's old collectibles before the emitter was invalidated, then legitimately re-execute again. The gated variant stages the same overlap deterministically. Co-authored-by: Luke Sandberg <210140+lukesandberg@users.noreply.github.com>
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October 19, 2026 21:01
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What?
Removes the
collector_is_not_re_executed_for_collectibles_it_has_not_read_yettest fromturbo-tasks-backend'scollectibles_outdated_dependency.rs. The other variant (gated_collector_is_not_re_executed_for_collectibles_it_has_not_read_yet) stays, and its behaviour is unchanged.Why?
The ungated test failed intermittently on canary with
take=âĶ: executions after the input change(left 2, right 1).The cause is the race that the module's doc comment already described, not a backend bug.
State::setinvalidates its readers one by one. When the collector is invalidated before the emitter, it re-executes right away, its strongly consistent read of the still-clean source returns at once, and it reads the old collectibles. When the new collectibles arrive, it re-executes again, as it should. Instrumentation confirmed this in every failure: the extra execution readcount=200but saw 5 collectibles. It reproduced in about 2 of 120 serial release runs under CPU load.So "exactly one execution" can't be asserted without controlling that order.
I was not very confident about this test when it was added, so dropping it seems reasonable.