fix(ci): pin nightly fuzz to x86_64-unknown-linux-gnu#39
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cargo-fuzz defaults to x86_64-unknown-linux-musl on Linux; libfuzzer-sys
enables -Zsanitizer=address by default, and rustc rejects ASan with a
statically-linked musl libc:
error: sanitizer is incompatible with statically linked libc,
disable it using `-C target-feature=-crt-static`
error[E0463]: can't find crate for `core`
All 12 fuzz-long targets in nightly.yml have been failing with this since
the workflow was added on 2026-04-24. The same-day follow-up 1d7723a fixed
fuzz-smoke.yml with `--target x86_64-unknown-linux-gnu` but missed this
file; cron didn't fire until the first scheduled run on 2026-05-04, so the
breakage went unnoticed for 10 days.
Mirror the proven fix from fuzz-smoke.yml. Single-line change. No -Z
build-std rebuild cost; no clobbering of RUSTFLAGS that libfuzzer-sys
also writes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Nightly has been red every night since 2026-05-04 — all 12
fuzz-longmatrix targets failing with:```
error: sanitizer is incompatible with statically linked libc,
disable it using `-C target-feature=-crt-static`
error[E0463]: can't find crate for `core`
note: the `x86_64-unknown-linux-musl` target may not be installed
```
Root cause. `cargo fuzz` defaults to `x86_64-unknown-linux-musl` on Linux. libfuzzer-sys enables `-Zsanitizer=address` by default. ASan + statically-linked musl libc are incompatible.
Why now. Workflow added in `894c98e` (PR #21, 2026-04-24). Same-day follow-up `1d7723a` fixed
fuzz-smoke.ymlby pinning `--target x86_64-unknown-linux-gnu` but missednightly.yml. Cron only fires at 03:00 UTC, so the regression silently sailed past until the first scheduled run on 2026-05-04 — 10 days unnoticed.Fix. Mirror the proven `fuzz-smoke.yml` pattern. One-line change.
PR #35 (smithy-migration) is orthogonal — its diff only touches `fuzz-smoke.yml` + `sanitizers.yml`; this regression would persist after #35 lands.
Test plan
🤖 Generated with Claude Code