The full-README competitor matrix ranked lua/kong as the largest
legitimate fresh-index gap (2.71×). Stage attribution (RESOLVE_PROFILE=2)
pinned it: resolveLuaRequire ran getAllFiles().filter(endsWith) FOUR
times per require ref — ~7.5k string suffix scans each, measured at
~0.9ms/ref, hit or miss (2.7s combined over kong's 3k requires).
Replace the per-ref full-list scans with a per-context basename →
file-paths index (the cobolCopybookIndexes pattern). Buckets preserve
getAllFiles() iteration order, so each suffix's candidate filter yields
exactly the array the full scan produced — identical matches, identical
stable sort, identical winner, dump-proven.
kong: 4.07-4.27 → 3.40-3.63s (−16%). Gates: kong old-vs-new dump
byte-identical (157,650 rows), kong pooled-vs-sequential identical,
Fusion (luau instance-path requires) old-vs-new identical; suite
2,689 ×2 with CODEGRAPH_KERNEL_EXPECT=1.
Also registers cobolCopybookIndexes in clearImportResolverMemos — it was
never dropped on cache clears, so post-sync copybook lookups could serve
a stale file list; cache-drop is the always-safe direction.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Colby McHenry
b8bfa1a58d