Target 4 from the fuzzing plan (the alkcall-bug-class hunt): a
#[derive(Arbitrary)] op sequence drives the producer session pump
(drive_session_pre_negotiated) over a duplex pair against a fuzz-local
mock backend.
- fuzz/shared/src/session_opseq.rs: op vocabulary (client writes incl.
invalid-type/oversize-length barrier probes, backend production/EOF,
exit resolve/fail/drop, control messages, bounded reads, yields),
kill-guard exit future (ADR-005 observability), delivery model, and
the invariants: kill-on-Drop (kill_fired == !exit_resolved), exit
chunk is last with first-issued code -1 on wait-failure (ADR-004),
lossless per-stream FIFO + single stdout sentinel, stdin
prefix-losslessness (post-shutdown chunks never delivered), control
dispatch bounds, take-once allocation, teardown termination.
- Harness-model correction caught by a 60s smoke run before the
campaign (the alkcall §7.7 pattern, third time): a failed client
write can mean the session completed and dropped the server duplex
half while the write was in flight - the harness now drains and
requires the exit chunk on any write/shutdown error (premature close
without it is a finding). No adapter code changed.
- 12 committed seeds via the deterministic generator, hand-encoded
against the arbitrary 1.4.x derive layout; the encoding is pinned by
a seed-decode test. Existing chunk_frame/negotiation_frame/
control_json seed corpora are byte-identical to before.
- fuzz/.gitignore: the per-target seed negations never matched (corpus/*
excludes the parent dir; git cannot re-include beneath an excluded
dir). Fixed with the !corpus/*/ + corpus/*/* + !corpus/*/seed-*
recipe - new seed files were silently ignored until now.
- Campaign: 10 min detached via run-detached.sh, exited 0, artifact
dir empty - 42.3k execs across 33 fork jobs, 0 crash/oom/timeout,
cov 3934 -> 4075 edges. Grown corpus excised per the corpus policy.
Verification: corpus replay green on stable (9 tests), cargo test 113
+ --all-features 156, clippy stable/wasm/fuzz-shared, fmt, doc,
publish dry-run, wasm check - all pass.
- Bump alkcall 0.8.0 -> 0.8.1 (duplicate adopt/open channel-state
destruction fix from alkcall's fuzz campaign; AGENTS.md stale-pin fix).
- Adopt fuzzing per docs/plans/fuzzing.md (mirrors alkcall's
docs/research/fuzzing.md as-built layout): fuzz/ workspace with own
[workspace] table, nightly pinned for the subtree only, invariant
logic in a stable-toolchain shared crate.
- Targets: chunk_frame (5-byte chunk codec), negotiation_frame
(negotiation framing + NegotiateRequest + error_response_bytes +
the cross-codec peek-disambiguation seam), control_json
(ControlMessage JSON + signal_from_name). src/local/ out of scope
(not wire-attacker-shaped).
- 328 committed seeds (deterministic generator); grown corpora
gitignored. Corpus replay on stable is the standing fuzz gate
(cargo test --manifest-path fuzz/shared/Cargo.toml).
- Detached-runner rule (fuzz/run-detached.sh): campaigns never run in
the foreground of an agent session - OOM in a target must cost the
fuzzer, never the session host.
- Root Cargo.toml gained [workspace] members/exclude (MSRV vs fuzz
nightly dev-deps footgun) and fuzz/ in the publish exclude.
Verification: cargo test (113), cargo test --all-features (156),
clippy stable + wasm32-unknown-unknown, fmt, doc, publish dry-run,
corpus replay 328 seeds - all green. 10-min detached campaigns on all
three targets: 0 crashes/hangs/OOMs/leaks (chunk_frame cov-saturated
at 710 edges; negotiation_frame 3.69M execs cov 3157; control_json
8.6M execs cov 2035). Corpus replay caught three harness-model
mismatches pre-campaign (payload-slice shape; the negotiation framing
layer is length-prefix-only - Json unreachable from read_frame;
zero-length frames admitted by the reader, rejected by the adapter's
parse). Campaigns recorded in docs/plans/fuzzing.md section 8.
glm-5.3-flash