Cheap filename-only filter the detector pass uses to skip #detect on files the detector cannot possibly match. The default true preserves prior behavior (every detector runs on every file). Override with the same predicate the body of #detect starts with — e.g., filename.ends_with?(".py") for a Python framework detector — so the detector loop avoids the #detect dispatch on files outside the detector's language.

On large codebases (saleor's 4255 .py files) this lifts ~100 virtual #detect calls per file out of the hot loop because most detectors' inner first-line is exactly this kind of cheap filename check.

Detect from go.mod (whole-repo scans) AND any .go file that imports go-zero. The .go path lets a microservice sub-directory (e.g. service/order/api, whose go.mod lives at the monorepo root) still be recognized when scanned on its own. The analyzer re-gates every file on the same marker, so this can't over-extract.