[bug-hunter] pr-comment.sh exits silently when --severity/--title/--why value is missing #1879

Impact

claude-workflows/pr-review/scripts/pr-comment.sh can exit with status 1 and no error output when a required flag value is omitted (for --severity, --title, or --why). This makes PR review automation fail without actionable diagnostics, increasing triage/debug time for users and maintainers.

Reproduction Steps

1. Save and run this new minimal failing test:

#!/usr/bin/env bash
set -euo pipefail

repo_root="/home/runner/work/ai-github-actions/ai-github-actions"
script="$repo_root/claude-workflows/pr-review/scripts/pr-comment.sh"

tmp_out="$(mktemp /tmp/gh-aw/agent/pr-comment-test-out.XXXXXX)"
tmp_err="$(mktemp /tmp/gh-aw/agent/pr-comment-test-err.XXXXXX)"

set +e
PR_REVIEW_REPO="elastic/ai-github-actions" \
PR_REVIEW_PR_NUMBER="1" \
bash "$script" "README.md" "1" --severity >"$tmp_out" 2>"$tmp_err"
rc=$?
set -e

if [[ $rc -eq 0 ]]; then
  echo "Expected non-zero exit for missing --severity value, got success"
  exit 1
fi

# Failing assertion: parser should emit actionable error text, but currently emits nothing.
if [[ ! -s "$tmp_err" ]]; then
  echo "FAIL: stderr is empty; expected actionable error message for missing --severity value"
  exit 1
fi

if ! grep -q "Error:" "$tmp_err"; then
  echo "FAIL: stderr missing 'Error:' prefix"
  cat "$tmp_err"
  exit 1
fi

echo "PASS"

2. Execute it:

chmod +x /tmp/gh-aw/agent/test_pr_comment_missing_value.sh
/tmp/gh-aw/agent/test_pr_comment_missing_value.sh

Expected vs Actual

Expected: Script exits non-zero and prints an actionable error message indicating a missing value for --severity (similarly for --title/--why).

Actual: Script exits non-zero with empty output.

Observed output:

FAIL: stderr is empty; expected actionable error message for missing --severity value

Failing Test

/tmp/gh-aw/agent/test_pr_comment_missing_value.sh (full script shown above) fails deterministically.

Evidence

• Parser branches assign from $2 and immediately shift 2 without checking argument count:
  • claude-workflows/pr-review/scripts/pr-comment.sh#L73-L84
• set -e is enabled:
  • claude-workflows/pr-review/scripts/pr-comment.sh#L35
• With a trailing flag missing its value (e.g., --severity), shift 2 fails and exits before any user-friendly validation/error path.
• Related historical context reviewed:
  • [text-auditor] Fix typo drift and non-actionable unknown-argument errors #1104 and PR Improve unknown-argument errors for issue tooling scripts #1105 improved unknown-argument messaging, but this missing-value path remains unhandled and reproducible.

Suggested Actions

• Add explicit missing-value checks for --severity, --title, and --why in argument parsing before shift 2.
• Add a small regression test/script asserting non-empty actionable stderr for missing flag values.

What is this? | From workflow: Trigger Bug Hunter

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• expires on Aug 28, 2026, 11:19 AM UTC