fix(hack): guard empty-array expansion in lint-drift for bash 3.2#117
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omergk28 wants to merge 1 commit into
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fix(hack): guard empty-array expansion in lint-drift for bash 3.2#117omergk28 wants to merge 1 commit into
omergk28 wants to merge 1 commit into
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Stock macOS ships bash 3.2 (GPLv2 freeze), which treats
"${arr[@]}" on an empty array as an unbound variable under
set -u — bash 4.4+ does not. drift_grep expands its exclude
array unconditionally and several call sites pass no excludes,
so make lint-style (and therefore make audit, the mandatory
pre-PR gate) aborted on every stock Mac before running a single
drift check.
Guard with the parameter-expansion alternate form,
${arr[@]+"${arr[@]}"}: empty expands to zero words, populated
reproduces the original quoted expansion, bash 4+ behavior
unchanged. The other hack/ array expansions are safe today
(count-guarded or hardcoded non-empty); details in the spec.
Captures the gotcha in LEARNINGS.md so the next session does
not re-debug it.
Spec: specs/fix-lint-drift-bash32-empty-array.md
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Omer Kocaoglu <omergk28@gmail.com>
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Summary
make audit— the contributing guide's mandatory pre-PR gate — aborts on stock macOS before running a single drift check:bash 3.2 (the newest Apple ships, frozen at the GPLv2 boundary) treats
"${arr[@]}"on an empty array as an unbound variable underset -u; bash 4.4+ does not.drift_grepexpands itsexclude_argsarray unconditionally and several call sites pass no excludes, so every macOS contributor hits this on the very first audit.Fix
Guard the expansion with the canonical parameter-expansion alternate form
${arr[@]+"${arr[@]}"}: an empty array expands to zero words, a populated array reproduces the original quoted expansion, and bash 4+ behavior is unchanged. The otherhack/array expansions were checked empirically — all safe today (count-guarded or hardcoded non-empty); details in the spec.Verification
bash hack/lint-drift.shnow exits 0.go build ./...clean.specs/fix-lint-drift-bash32-empty-array.md; the gotcha is captured inLEARNINGS.mdso the next session doesn't re-debug it.Provenance
Split out of #113 (the #93 TOCTOU fix) so each PR carries a single concern, per the contributing guide. This is an independent commit touching disjoint files (
hack/lint-drift.sh, its spec, and a LEARNINGS entry).🤖 Generated with Claude Code