fix(hooks): use POSIX [[:space:]] in guard-git.sh grep patterns

[carlos-alm]

Summary

• Replace all remaining \s shorthand with POSIX [[:space:]] in the grep -qE patterns of .claude/hooks/guard-git.sh.
• BSD/GNU grep accept \s in ERE mode as a vendor extension, but it is not POSIX. Stricter graps (e.g. busybox in Alpine) treat the pattern literally and miss matches.
• Mirrors the convention established for the sed patterns in fix(hooks): guard-git.sh sed patterns work on macOS BSD sed #1146 — the file is now uniformly portable.

Context

Follow-up to Greptile feedback on PR #1153, which was closed as superseded by #1146 before this suggestion could be addressed. Tracked in #1157.

No behavior change on macOS or stock Linux runners (BSD/GNU grep both keep matching). The fix only affects POSIX-strict environments where \s was silently treated as a literal s.

Test plan

• bash -n .claude/hooks/guard-git.sh — syntax check
• Manual pattern checks on macOS BSD grep: git add ., git add -A, git add --all, git reset, git restore --staged, git push, gh pr create, git commit, cd /tmp && git status, and tab-separated variants — all match as before; git add file.txt and echo hello still no-match.
• CI green

Closes #1157

[claude]

Claude finished @carlos-alm's task —— View job

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PR Review Complete

Root Cause Analysis

Problem Being Solved: The guard-git.sh hook uses \s shorthand in grep -qE patterns, which is a vendor extension (GNU/BSD grep) but not POSIX-compliant. This causes silent failures on stricter grep implementations like busybox in Alpine containers, where \s is treated literally as the character 's' rather than as a whitespace matcher.

Why This Approach: This is a legitimate portability fix, not a workaround. The PR correctly addresses the root cause by replacing non-portable regex syntax with POSIX-compliant equivalents. It follows the same pattern established in #1146 for sed patterns, ensuring uniform compliance across the entire file.

Risk Assessment: ✅ LOW RISK - Pure compatibility improvement with no behavior change on existing systems.

Phase Analysis

Phase 1: ✅ Root Cause - LEGITIMATE FIX

This addresses a real portability issue, not symptom masking. The \s shorthand fails silently on strict POSIX systems, allowing dangerous git commands to pass through unchecked.

Phase 2: ✅ Configuration Changes - NOT APPLICABLE

No configuration files, linting rules, or test thresholds modified. This is purely a pattern syntax fix.

Phase 3: ✅ Test Integrity - NOT APPLICABLE

No test files modified or assertions weakened.

Phase 4: ✅ Code Quality Review

Excellent quality:

• Consistent transformation: All 12 occurrences systematically replaced
• Preserves functionality: [[:space:]] is functionally equivalent to \s but POSIX-compliant
• Pattern accuracy: Each replacement correctly handles word boundaries and spacing
• Comment updates: Line 30 comment updated to reflect the new syntax
• No regressions: BSD/GNU grep continue to work identically

Key changes verified:

• Line 25: Git command detection pattern
• Lines 56, 61, 66, 71-72, 78, 83: Dangerous command blocking patterns
• Lines 161, 167, 175: Branch validation and commit patterns
• All maintain identical matching semantics with better portability

Phase 5: ✅ Backlog Compliance

Backlog Compliance

• Zero-dep: ✅ — No new dependencies, pure shell script fix
• Foundation-aligned: ✅ — Improves P4 (zero-cost core) by ensuring hooks work across all POSIX environments
• Problem-fit: 3/5 — Infrastructure improvement that ensures hooks function correctly for AI agents, but doesn't directly address core navigation/orientation problems
• Breaking: No — Purely additive compatibility, no API/CLI changes
• Tier: 1 (zero-dep ✓ + foundation-aligned ✓)

Critical Concerns

None identified. This is a well-executed portability fix.

Final Recommendation

• Rating: ⭐⭐⭐⭐☆ (4/5)
• Action: APPROVE
• Reasoning: High-quality portability fix that eliminates silent failures on strict POSIX systems. Consistent implementation, no behavior change on existing systems, and follows established patterns from fix(hooks): guard-git.sh sed patterns work on macOS BSD sed #1146. The only reason this doesn't get 5 stars is that it's infrastructure maintenance rather than a breakthrough feature.

Recommendation: Approve and merge. This fix ensures the guard-git.sh hook works reliably across all deployment environments.

[greptile-apps]

Greptile Summary

This PR completes the POSIX portability cleanup of guard-git.sh by replacing all remaining \s ERE shorthands in grep -qE patterns with the POSIX character class [[:space:]]. The sed patterns were already updated in PR #1146; this follow-up makes the grep patterns consistent and ensures the hook functions correctly on POSIX-strict environments (e.g. busybox grep in Alpine) where \s is treated as a literal s.

• All 11 occurrences of \s in grep -qE patterns replaced with [[:space:]] — no logic change, purely a portability fix.
• The inline code comment on line 30 was also updated to match the new notation, keeping documentation in sync with the patterns.

Confidence Score: 5/5

Safe to merge — purely mechanical substitution of non-POSIX shorthand with its portable equivalent, with no changes to matching logic.

Every \s in grep -qE patterns has been replaced with [[:space:]], which is the correct POSIX ERE equivalent. The sed patterns were already using [[:space:]], and the remaining grep calls in detect_work_dir (lines 122, 128) were never using \s and are untouched. The test plan covers the full set of command patterns the hook guards. No behavioral change on BSD/GNU grep; the fix only matters on POSIX-strict grep implementations where \s was silently treated as literal s.

No files require special attention.

Important Files Changed

Filename	Overview
.claude/hooks/guard-git.sh	All \s shorthands in grep -qE patterns replaced with POSIX [[:space:]]; sed patterns were already POSIX-compliant from PR #1146, so the file is now uniformly portable with no logic changes.

_{Reviews (2): Last reviewed commit: "Merge branch 'main' into fix/1157-guard-..." | Re-trigger Greptile}