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fix: key melange cache by cargo profile - #68
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falcorocks merged 1 commit intoOct 9, 2026
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The melange cache key hashed only the lockfiles, so caches saved by default-branch maxperf builds were restored by fast-build PR builds as an exact hit. Nothing in a maxperf target/ is reusable under fast-build, so PRs paid the multi-GB restore and then recompiled every crate (2002 crates on optimism's op-stack-rust leg). Include the cargo profile in both the key and the restore-keys prefix, terminated with '.' so one profile's prefix never matches another's. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
falcorocks
approved these changes
Oct 9, 2026
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Problem
melange-build.yamlkeys the GHA cache onmelange-v2-<stack>-<arch>-<lockfile hash>. The cargo profile isn't part of the key. Inoptimism, theop-stack-rustleg buildsmaxperfon develop/tags (the only runs that save) andfast-buildon PRs (restore-only). So every internal PR restores the multi-GBmaxperfcache as an exact hit (cache-hit=true) and then reuses nothing:Change
restore-keysprefix:melange-v2-<stack>-<arch>-<profile>.<lockfile hash>. Callers with no profile getnone..rather than-..can't appear in a cargo profile name, so…-release.never prefix-matches…-release-perf.….Effect / caveats
optimismbuildsfast-buildtoday, so nothing writes afast-buildcache. That needs a consumer-side change: a default-branch leg that builds the PR profile. It's tracked separately because it costs runner time and Actions cache space (the repo already holds ~9 GB of melange cache).melange-v2-*entries age out unused.Testing
maxperf,fast-build,release,release-perfand empty: distinct keys, no cross-profile prefix match.🤖 Generated with Claude Code