mapclearloop enforce-readiness: clean, type-resolved, autofix-verified, zero production violations — but its already-enforced si [Content truncated due to length]

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Summary

mapclearloop (range-delete loop over a map → clear(m)) is production-ready for CI enforcement but is absent from the enforced analyzer list. Its sibling mapdeletecheck — same package family, same author style, added in the same wave — is already enforced (.github/workflows/cgo.yml:1208 and the wasm gate at :1211). mapclearloop is arguably the more careful of the two (it has a comment-preservation guard that mapdeletecheck still lacks, see #46130), yet it is the one left out of the gate.

Evidence

Enforced list today (cgo.yml:1208) — mapdeletecheck present, mapclearloop absent

make golint-custom LINTER_FLAGS="-errstringmatch -panicinlibrarycode -manualmutexunlock \
  -osexitinlibrary -rawloginlib -logfatallibrary -regexpcompileinfunction -fprintlnsprintf \
  -strconvparseignorederror -jsonmarshalignoredeerror -uncheckedtypeassertion -fmterrorfnoverbs \
  -tolowerequalfold -httpnoctx -timeafterleak -errortypeassertion -execcommandwithoutcontext \
  -sprintfint -stringsindexcontains -stringscountcontains -bytesbufferstring -ioutildeprecated \
  -mapdeletecheck -test=false"

mapclearloop appears nowhere in cgo.yml (prod or wasm gate).

Correctness of the analyzer (pkg/linters/mapclearloop/mapclearloop.go):

• Type-resolved throughout — no syntactic package/name matching. Map type is verified via pass.TypesInfo.TypeOf(rangeStmt.X).Underlying().(*types.Map) (mapclearloop.go:59-65); delete is confirmed to be the builtin via pass.TypesInfo.Uses[delIdent].(*types.Builtin) (:104-107); the map and key are matched by object identity (sameObject, :190-208).
• Shadow-safe fix: clear is only emitted after builtinVisibleAtPos(pass.Pkg, rangeStmt.Pos(), "clear") confirms the clear builtin is not shadowed at the site (:131, :157-171). This is the correct guard for emitting a builtin the source did not already contain.
• Comment-safe fix: the SuggestedFix is suppressed (diagnostic still reported) when a comment overlaps the replaced span, via hasOverlappingComment(pass.Files, rangeStmt.Pos(), rangeStmt.End()) (:140-149). This is exactly the guard mapdeletecheck: autofix silently deletes comments inside the if body — no comment guard, unlike its sibling mapclearloop #46130 asks mapdeletecheck to adopt — mapclearloop already has it.
• Wires generated-file skip (filecheck.ShouldSkipFilename) and per-line suppression (nolint.HasDirectiveForLinter), consistent with the rest of the family.
• Autofix is golden-verified: mapclearloop_test.go:15 uses analysistest.RunWithSuggestedFixes (not the weaker analysistest.Run), so the emitted clear(...) text is checked against .golden. This closes the verification-parity class from Autofix verification-parity gap: 3 of 9 SuggestedFix linters (stringsindexcontains, sprintfint, stringreplaceminusone) have zero [Content truncated due to length] #43313.

Zero production violations (the enforce-readiness bar):
A repo-wide search for the exact shape it flags — a range-over-map loop whose sole body statement is delete(m, k) — returns only testdata under pkg/linters/mapclearloop/testdata/. The nearest production hit, pkg/cli/devcontainer.go:316-319, is not a violation: its loop body is a guarded if ... { delete(existing, key) }, not a bare unconditional delete, so mapclearloop (which requires len(rangeStmt.Body.List) == 1 and the single statement to be the delete call, :88-110) correctly does not flag it. Adding -mapclearloop to the gate therefore turns green immediately and locks in the invariant going forward (clear(m) is the Go 1.21+ idiom and also correctly clears NaN-keyed entries that a delete-loop cannot reach).

Impact

• Consistency gap: the map-family pair is split across the enforcement boundary for no principled reason — the less guarded member is enforced, the more guarded one is not.
• Regression risk: without the gate, a future for k := range m { delete(m, k) } can land in production un-flagged even though the analyzer that catches it already exists and is green.

Recommendation

Add -mapclearloop to both LINTER_FLAGS invocations in .github/workflows/cgo.yml (the prod gate at :1208 and the wasm gate at :1211), alongside -mapdeletecheck.

Before (cgo.yml:1208):

... -bytesbufferstring -ioutildeprecated -mapdeletecheck -test=false

After:

... -bytesbufferstring -ioutildeprecated -mapclearloop -mapdeletecheck -test=false

Validation checklist

• make golint-custom LINTER_FLAGS="-mapclearloop -test=false" passes on main (zero production findings).
• Same for the wasm gate (GOOS=js GOARCH=wasm ... LINTER_PACKAGES="./pkg/console ./pkg/parser ./pkg/styles ./pkg/tty ./pkg/workflow").
• -mapclearloop added to both cgo.yml flag strings next to -mapdeletecheck.
• (Optional, tracked separately in mapdeletecheck: autofix silently deletes comments inside the if body — no comment guard, unlike its sibling mapclearloop #46130) lift the shared hasOverlappingComment guard into internal/astutil so mapdeletecheck can adopt it too.

Effort: trivial (two one-token edits in cgo.yml); the analyzer and its RWSF golden already exist and pass.

Non-duplicate note

Prior enforce-readiness issues covered different linters: #45629 (bytesbufferstring / mapdeletecheck / ioutildeprecated), #45186 (stringsindexcontains / stringscountcontains). mapclearloop was in none of them and appears in no open or closed sergo issue title — this gap is genuinely untracked. This is distinct from #46130, which is about mapdeletecheck's missing comment guard, not enforcement of mapclearloop.

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• expires on Jul 24, 2026, 8:52 PM UTC-08:00

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