fix(op-service/eth): make FuzzDetectNonBijectivity deterministic#20939
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fix(op-service/eth): make FuzzDetectNonBijectivity deterministic#20939ajsutton wants to merge 1 commit into
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The fuzz function captured a shared *rand.Rand outside the f.Fuzz closure and used it to pick which bit to flip on each iteration. Go's fuzz engine requires fuzz targets to be deterministic for the same input — it re-runs inputs to verify reproducibility, to gather baseline coverage, and during minimization. A shared rand source meant the same input produced different behavior on re-execution, which causes worker subprocesses to stall during minimization and ultimately exit with EOF (#20936). Derive the bit to flip from a SHA-256 of the input instead, so the target is a pure function of its input. The shared Blob buffer outside the closure is fine — within one worker subprocess the fuzz callback runs sequentially.
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Claude: Combined into #20940 — CI on this branch alone was failing because the load-bearing fix (the |
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Claude: Authored by Claude on Adrian's behalf.
The shared
*rand.Randadvanced state between calls, so the fuzz target was not a pure function of its input. Go's fuzz engine stalls when re-execution of an input differs, producingprocess hung ... while minimizing: EOF. Replace withsha256(d)-derived bit selection.Closes #20936