Skip to content

GC Ratchet cannot gate 07_array_grow_evacuate: copied_bytes/freed_bytes are nondeterministic across traced runs #9790

Description

@proggeramlug

GC Ratchet fails on every main run with:

gc-ratchet error: 07_array_grow_evacuate: GC counters are not deterministic
across traced runs (copied_bytes, freed_bytes); they cannot be gated

The gate is behaving correctly — it refuses to gate a counter it cannot reproduce.

This is not baseline drift. The current run reports zero REGRESSION cells. (Earlier runs in the window did show 42 drifted cells, but those are gone; the nondeterminism is what remains.)

Two possibilities, and the order to rule them out

  1. The collector's copied/freed accounting became run-dependent on this workload. This is the more interesting answer and should be excluded first — it would be a real GC finding wearing a CI failure as a disguise.
  2. The fixture itself became nondeterministic.

Done when

07_array_grow_evacuate is deterministic across traced runs, or it is removed from the gated set with the reason recorded.

Context

GC Ratchet has been red on main continuously since 2026-08-31. It is not a pr-gate context, so nothing blocks on it and the failure has been invisible.

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions