fix(ci): correct ccache variable CCACHE_IGNOREOPTIONS (was non-existent REGEX variant)#449
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The variable CCACHE_IGNOREOPTIONSREGEX does not exist in ccache — it was silently ignored, so SLIC3R_DEV_TIMESTAMP stayed in the hash and every build saw ~90% cache misses regardless of warm caches. Per ccache 4.10 manual the correct variable is CCACHE_IGNOREOPTIONS, which uses shell wildcards (not regex): a trailing '*' matches any suffix. Changed '-DSLIC3R_DEV_TIMESTAMP=.*' (regex) to '-DSLIC3R_DEV_TIMESTAMP=*' (wildcard). Affects Debian, Fedora, Arch (cd-packages.yml) and Ubuntu, macOS (_build-core.yml). Expected: ~9% -> ~90%+ hit rate on the next warm run. Source: https://ccache.dev/manual/4.10.html (ignore_options)
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## The real reason the cache never warmed up GitHub Actions caches are **immutable**. The `-latest` stable-key approach (PR #445) meant that once `ccache-<platform>-latest` existed (from #60, with broken timestamp hashes), every later save failed with **'Cache save failed'** — the stale cache was frozen forever. Even the correct `CCACHE_IGNOREOPTIONS` fix (#449) could never store a clean cache. ([github-action-benchmark#273](benchmark-action/github-action-benchmark#273)) ## Fix - Keys back to `ccache-<platform>-${{ github.run_id }}` — unique per run, save always succeeds; `restore-keys` prefix finds the newest previous cache. - `CCACHE_MAXSIZE` 5G → 2G so big ccache entries don't evict the small (165 MB) deps caches from the 10 GB repo limit — the original eviction problem `-latest` tried (and failed) to solve. After this + #449, the first warm run stores clean hashes, the next hits ~90%.
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Root cause of the persistent 9% hit rate
CCACHE_IGNOREOPTIONSREGEXdoes not exist in ccache — it was silently ignored. So-DSLIC3R_DEV_TIMESTAMP=<sekunde>stayed in the hash and every build had ~90% misses, even with a warm-latestcache (confirmed: cache restored successfully in #61, still 9.20% hits).Fix
Per the ccache 4.10 manual, the correct variable is
CCACHE_IGNOREOPTIONS, using shell wildcards (not regex) — a trailing*matches any suffix:CCACHE_IGNOREOPTIONSREGEX=-DSLIC3R_DEV_TIMESTAMP=.*(regex, ignored)CCACHE_IGNOREOPTIONS=-DSLIC3R_DEV_TIMESTAMP=*(wildcard, works)Applies to all 6 occurrences: Debian, Fedora, Arch, Ubuntu, macOS.
Expected: ~9% → ~90%+ hit rate on the next warm run → Linux builds drop from ~60 min to ~10 min.