fix(markdown-formatter): guard EPOCHREALTIME for Bash < 5 portability

[kyle-sexton]

Summary

Propagation follow-up from #16's Codex review: markdown-formatter carried the identical latent bug.

EPOCHREALTIME is Bash 5.0+. The hook's start=$EPOCHREALTIME under set -u aborts on Bash 3.2/4.x (e.g. stock macOS) before the advisory exit 0 — failing every Write/Edit, not just markdown ones (the capture runs before the file-type filter).

Fix

• Default the stamp: start=${EPOCHREALTIME:-} (no set -u abort).
• emit_tel wrapper skips telemetry when the stamp is empty, so the hook still formats on older bash; the high-res envelope is simply omitted there.
• hook-utils.sh stays byte-identical to the bash-lint copy (the guard lives in the hook, not the lib).
• Version 0.1.0 → 0.1.1 so already-installed consumers receive the fix.

Verification (all green locally)

• shellcheck · editorconfig · typos · markdownlint (0 errors) · comment-hygiene
• claude plugin validate --strict passed
• Tests: markdown-format.test.sh 41/0, hook-utils.test.sh 37/0
• Confirmed hook-utils.sh byte-identical to plugins/bash-lint/hooks/hook-utils.sh

🤖 Generated with Claude Code

[claude]

Claude finished @kyle-sexton's task in 1m 48s —— View job

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PR Review: fix(markdown-formatter): guard EPOCHREALTIME for Bash < 5 portability

• Gather context and understand the request
• Read PR diff and changed files
• Review plugin.json version bump
• Review markdown-format.sh changes
• Review README.md changes
• Post comprehensive review feedback

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Summary

This is a correct, minimal, and well-scoped bug fix. The root cause was that start=$EPOCHREALTIME under set -uo pipefail would abort the entire hook on Bash < 5 (e.g. macOS stock Bash 3.2) — before the file-type filter ran — causing every Write/Edit to silently fail. The fix is a faithful propagation of the same pattern applied to bash-lint in PR #16.

Verdict: approve — no blockers.

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markdown-format.sh — Core Fix

The guard (line 25):

start=${EPOCHREALTIME:-}

Correct. ${VAR:-} is portable back to POSIX sh; it silences set -u by providing an empty default when the variable is unset. On Bash < 5, start becomes the empty string, then the emit_tel wrapper short-circuits before any hook::emit_telemetry call that would itself hit local now=$EPOCHREALTIME under set -u.

The wrapper (lines 30–33):

emit_tel() {
  [[ -n "$start" ]] || return 0
  hook::emit_telemetry "$@"
}

Clean approach for three call sites. Using a closure over the outer-scope $start is idiomatic here since start is a script-level variable — no ambiguity. Checked all three call sites are correctly updated (lines 86, 93, 121); no stray hook::emit_telemetry direct calls remain.

hook-utils.sh byte-identical: confirmed with diff — no divergence from the bash-lint copy, which is the right constraint to maintain for future syncs.

Pattern fidelity: the implementation matches bash-lint.sh exactly (confirmed with grep). This is correct propagation, not a novel approach.

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plugin.json — Version Bump

0.1.0 → 0.1.1 is the right semver increment for a bug fix. Already-installed consumers will receive the patch on next update. ✓

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README.md — Docs

The added paragraph clearly communicates the compatibility baseline and the graceful degradation behavior. It belongs in the Requirements section. ✓

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Minor Observation (non-blocking)

The comment block at lines 27–29 slightly echoes the comment already at lines 21–24 and also what the emit_tel code itself expresses. Given the existing comment density in the file this is a judgment call — the extra comment does no harm and follows the style established in the bash-lint copy.

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Checklist

Concern	Status
set -u abort on Bash < 5 fixed	✓
No regression on Bash 5+ (empty guard is a no-op when EPOCHREALTIME is set)	✓
All three hook::emit_telemetry call sites replaced	✓
hook-utils.sh byte-identical to bash-lint copy	✓
Pattern matches bash-lint fix	✓
Version bump correct	✓
README updated	✓