chore: conditionally enable OpenRewrite FQCN shortening in CI

Instead of always running OpenRewrite (which quadruples build time),
detect FQCNs in the diff and only enable -Prewrite when needed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: gnodet

etc/scripts/regen.sh

@@ -21,6 +21,34 @@ set -e
 # Move to top directory
 cd `dirname "$0"`/../..
 
+# Conditionally enable OpenRewrite FQCN shortening only when needed
+DIFF_BASE=""
+if [ -n "$GITHUB_BASE_REF" ]; then
+  git fetch origin "$GITHUB_BASE_REF" --depth=1 --quiet 2>/dev/null || true
+  DIFF_BASE="origin/$GITHUB_BASE_REF"
+elif git rev-parse HEAD~1 >/dev/null 2>&1; then
+  DIFF_BASE="HEAD~1"
+else
+  git fetch --deepen=1 --quiet 2>/dev/null || true
+  if git rev-parse HEAD~1 >/dev/null 2>&1; then
+    DIFF_BASE="HEAD~1"
+  fi
+fi
+
+if [ -n "$DIFF_BASE" ] && \
+   git diff "$DIFF_BASE"...HEAD -- '*.java' ':!*/src/generated/*' \
+     | grep '^+[^+]' \
+     | grep -v '^+ *import ' \
+     | grep -v '^+ *package ' \
+     | grep -v '^+ *//' \
+     | grep -v '^+ *\*' \
+     | grep -qE '[a-z][a-z0-9]*(\.[a-z][a-z0-9]*)+\.[A-Z]'; then
+  MAVEN_EXTRA_ARGS="${MAVEN_EXTRA_ARGS} -Prewrite"
+  echo "FQCNs detected in diff, enabling OpenRewrite (-Prewrite)"
+else
+  echo "No FQCNs detected in diff, skipping OpenRewrite"
+fi
+
 # Force clean
 git clean -fdx
 rm -Rf **/src/generated/