[Bug]: prevent label-sync failures when no issue is linked (#157)

.github/actions/label-sync/copy-linked-issue-labels/run.sh

@@ -4,13 +4,13 @@ set -euo pipefail
 title="$(jq -r '.pull_request.title // ""' "${GITHUB_EVENT_PATH}")"
 body="$(jq -r '.pull_request.body // ""' "${GITHUB_EVENT_PATH}")"
 pull_request_number="$(jq -r '.pull_request.number // ""' "${GITHUB_EVENT_PATH}")"
-issue_number="$(
-    printf '%s %s\n' "${title}" "${body}" \
-        | grep -oiE '(closes|fixes|resolves|addresses)\s+#[[:digit:]]+' \
-        | grep -oE '#[[:digit:]]+' \
-        | head -1 \
-        | tr -d '#'
-)"
+issue_number=''
+
+linked_issue_pattern='(closes|fixes|resolves|addresses)[[:space:]]+#([[:digit:]]+)'
+
+if [[ "${title} ${body}" =~ ${linked_issue_pattern} ]]; then
+    issue_number="${BASH_REMATCH[2]}"
+fi
 
 if [ -z "${issue_number}" ]; then
     echo "No linked issue was found in the pull request title or body."

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Keep the packaged pull-request label-sync action from failing when a PR does not reference any linked issue (#157)
+
 ## [1.17.0] - 2026-04-22
 
 ### Added