fix(ralph-wiggum): restore dead error handlers broken by set -euo pipefail

[sridhar-3009]

Problem

stop-hook.sh sets set -euo pipefail on line 7, but two patterns in the script silently exit the process before reaching their own error-handling code.

1. Frontmatter field extraction (lines 21–25)

ITERATION=$(echo "$FRONTMATTER" | grep '^iteration:' | sed 's/iteration: *//')

With pipefail, a grep no-match (exit 1) propagates as the pipeline exit code. set -e then exits the whole script immediately if any frontmatter field is absent from the state file (e.g. due to corruption or manual editing).

The corruption-detection guards on lines 28–48 can never be reached in that scenario, so the state file is left behind and the loop silently fails on every subsequent turn instead of cleaning up and stopping.

2. jq JSON parsing (lines 90–105)

LAST_OUTPUT=$(echo "$LAST_LINE" | jq -r '...' 2>&1)

# Check if jq succeeded
if [[ $? -ne 0 ]]; then   # ← dead code: set -e already exited above
  ...
fi

If jq fails (malformed transcript JSON), set -e exits the script before $? is ever checked. The state file is not cleaned up, and the loop remains stuck.

Fix

Frontmatter extraction — append || true to each pipeline so a missing field evaluates to an empty string rather than triggering set -e. The existing [[ ! "$FIELD" =~ ^[0-9]+$ ]] guards then handle the empty-string case correctly.

jq parsing — replace the separate if [[ $? -ne 0 ]] block with an inline || { ... exit 0; }. $LAST_OUTPUT is already set (via 2>&1) when the || block executes, preserving the diagnostic message.

Testing

bash -n stop-hook.sh passes. Manually verified the three scenarios:

• Normal (valid state file + valid transcript) → loop continues as before
• Missing iteration: field in state file → corruption message printed, state file removed, hook exits 0
• Malformed transcript JSON fed to jq → parse-error message printed, state file removed, hook exits 0

[stevei101]

Approved by Antigravity AI pair programmer after verifying CI checks pass.