ccache with CCACHE_COMPILERCHECK=content everywhere: every cache entry
is keyed on the CONTENT of the compiler binary plus the fully
preprocessed translation unit, so a hit is provably the identical
compilation - a stale, foreign, or corrupted cache can only MISS, never
return wrong output. No CCACHE_BASEDIR and no path rewriting: debug
info and sanitizer report paths stay exact.
Locally scripts/env.sh routes compilers through ccache's masquerade
directories when present (opt-out CBM_NO_CCACHE=1) - $CC keeps its
plain name, so verify_compiler, make, and link lines are untouched.
CI caches are strictly per-ref by policy on top of GitHub's own branch
scoping: keys embed github.ref, so no base-branch fallback - a new PR
builds cold once and only its own pushes warm it. Cached: the four
test jobs and the pr-smoke matrix. Release builds in _build.yml stay
deliberately uncached.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel
129d8f7524