test(util): skip build caches in source walker

[warelik]

Summary

test(util): skip build caches in source walker

The no-copy invariant source walker (forEachSourceFile) hard-coded a small
set of directories to skip before descending (.git, vendor,
node_modules, testdata). It did not skip the workspace's own build/tool
directories (.tmp_build, .go-cache, .go-tmp, .gocache), so the scan
could walk cloned or generated Go sources that must not be treated as product
code.

This PR generalizes the exclusion into a named skippedWalkDirs map and adds
the four build/tool dirs to it. Existing entries keep their exact behavior
(the switch becomes an equivalent map lookup, no walker behavior change for
entries already present).

Exact skip set

.git, vendor, node_modules, testdata, .tmp_build, .go-cache,
.go-tmp, .gocache

This is an explicit allow/skip list — not a broad "skip all hidden dirs"
weakening. Arbitrary hidden source directories (e.g. .hidden-source) are
still scanned by the walker.

Regression coverage

TestForEachSourceFileSkipsBuildDirs:

• seeds every listed skip dir under a temp root with a poisoned *.go file,
• asserts none of those dirs are walked (no FORBIDDEN content observed),
• seeds a .hidden-source dir and asserts it is scanned exactly once —
  guarding against an over-broad hidden-dir skip.

Verification (worktree-local GOCACHE, GOTMPDIR, TMPDIR)

• gofmt -l internal/util/nocopy_invariant_test.go — clean
• focused test normal, -race, -race -count=3 — PASS
• go test ./internal/util — ok; -race — ok
• go test ./... — all packages ok
• go build ./... — clean
• go vet ./internal/util — exit 0

Note: on this machine two packages (sdk/cliproxy, test) initially
failed with link: mkdir /tmp/go-link-*: operation not permitted — a system
/tmp permission issue unrelated to this change. Both pass when TMPDIR is
redirected to a writable directory.

Changes

• internal/util/nocopy_invariant_test.go (+54 / −2)

Mirror

CPA: router-for-me/CLIProxyAPI#4947 (identical changes)

[warelik]

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