Artifact 5e5c715722760d6f45c4eaaf9b5d495bf83c59e5869a0e0dd76bb57b007e3b53:
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src/delta_fuzz.zig
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2026-07-20 04:06:34
— part of check-in
[1abe1089c1]
on branch h9-fuzzcov
— fuzz: floor outcome reachability across the fuzz targets
serve_fuzz already fails a run when its generator stops reaching the dispatch arms it exists to exercise, and merge3 does the same for conflict shapes. Generalize that guard so a generator that has drifted to one outcome can no longer pass every no-crash round while testing nothing on the arm it dropped.
Six targets gain a measured reached-outcomes floor: delta decodeInt and targetSize (a decoded value vs MalformedDelta), artifact predicates (simple-pathname and wiki-name each accepting and rejecting), sync card parsers (push/igot/uvgimme each accepting and rejecting), logstore open (torn-tail recovery vs Corrupt), and transport deframe (a damaged container both decoding and being rejected). Every threshold is counted at a fixed seed, stated in the comment, and set below the arm's measured frequency; each floor gates above a minimum round count so short runs never trip it.
Every other target carries a one-line note on why its outcome space does not partition: round-trips have only a success arm, and several garbage generators reach only their reject arm, the accept arm covered by the round-trip and deterministic tests. (user: dmestas, size: 9531) [annotate] [blame] [check-ins using]
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2026-07-20 04:11:19
— part of check-in
[57d8994848]
on branch trunk
— Merge h9-fuzzcov: every fuzz target now guards its own reach
Only two targets asserted that their generator still reaches the interesting outcomes; the other 25 could rot to instant-rejection and pass every no-crash check while testing nothing. Six targets that split into distinct outcomes now carry a reached-outcomes floor above a measured minimum round count -- decode-bounded, target-size, predicates, adversarial sync parsers, logstore open, and unframe each must reach both their accept and reject arms, or the run fails. Thresholds are measured at a fixed seed and re-checked at a second, and each floor is proven to trip when the generator is biased to one arm. Single-outcome round-trip targets carry a one-line exemption instead of a vacuous assert. The measurement also named several generators that under-reach their target's arms; those are recorded for follow-up, not fixed here. (user: dmestas, size: 9531) [annotate] [blame] [check-ins using]
-
2026-07-20 04:06:34
— part of check-in
[1abe1089c1]
on branch h9-fuzzcov
— fuzz: floor outcome reachability across the fuzz targets