- library-mode, library-contract (cache dir plus the tmpdir npm root), and library-asyncfree now carry a plain/san path segment: both flavors run the same ordinary builds, and the nightly's concurrent both-flavor recipe raced ar/ranlib in the shared dirs ("can't open file ... lib.lib.a"); the per-build -san tag stays, it distinguishes explicitly-sanitized builds within one suite
- the same flavor split lands on npm-static's fixed npm-static-workspace dir (the two flavors even build with different sanitize flags there), provenance's shared outDir, and diagnostics' $TMPDIR/scriptc-diag scratch (some entries emit backend artifacts before failing)
- dec-oracle publishes in the differential/llvm/linux/windows lanes are now atomic (write tmp, rename): the content-keyed path is shared across flavors and lanes, and a truncate-and-rewrite could expose a torn oracle to a concurrent reader
- every other suite already keys its build dirs by a content hash that includes the flavor, and the CAS build cache folds the sanitized flags into its key, so those stay as they are
- proof: three consecutive concurrent both-flavor library-mode runs from a wiped cache all pass 45/45 with zero ar/ranlib failures, and a concurrent both-flavor run of all four library suites passes 125/125 in each flavor
Chris Tate