fix(lock): detect and remove stale locks from killed hook processes

Author: nnemirovsky

scripts/remove-rule.sh

@@ -159,9 +159,20 @@ acquire_lock() {
   deadline=$(( $(date +%s) + LOCK_TIMEOUT ))
   while :; do
     if mkdir "$LOCK_DIR" 2>/dev/null; then
+      printf '%s\n' "$$" > "$LOCK_DIR/pid" 2>/dev/null || true
       LOCK_HELD=1
       return 0
     fi
+    # Stale lock detection: check if holder PID is still alive.
+    if [ -f "$LOCK_DIR/pid" ]; then
+      local holder_pid
+      holder_pid="$(cat "$LOCK_DIR/pid" 2>/dev/null || true)"
+      if [ -n "$holder_pid" ] && ! kill -0 "$holder_pid" 2>/dev/null; then
+        rm -f "$LOCK_DIR/pid" 2>/dev/null || true
+        rmdir "$LOCK_DIR" 2>/dev/null || true
+        continue
+      fi
+    fi
     if [ "$(date +%s)" -ge "$deadline" ]; then
       return 1
     fi
@@ -171,6 +182,7 @@ acquire_lock() {
 
 release_lock() {
   if [ "$LOCK_HELD" -eq 1 ]; then
+    rm -f "$LOCK_DIR/pid" 2>/dev/null || true
     rmdir "$LOCK_DIR" 2>/dev/null || true
     LOCK_HELD=0
   fi

scripts/write-rule.sh

@@ -117,9 +117,25 @@ acquire_lock() {
   deadline=$(( $(date +%s) + LOCK_TIMEOUT ))
   while :; do
     if mkdir "$LOCK_DIR" 2>/dev/null; then
+      # Write our PID so stale-lock detection can check liveness.
+      printf '%s\n' "$$" > "$LOCK_DIR/pid" 2>/dev/null || true
       LOCK_HELD=1
       return 0
     fi
+    # Stale lock detection: if the lock dir exists but the holder PID is dead,
+    # forcibly remove it. This handles the case where a hook was killed by
+    # CC's timeout mid-write, leaving the lock behind.
+    if [ -f "$LOCK_DIR/pid" ]; then
+      local holder_pid
+      holder_pid="$(cat "$LOCK_DIR/pid" 2>/dev/null || true)"
+      if [ -n "$holder_pid" ] && ! kill -0 "$holder_pid" 2>/dev/null; then
+        # Holder is dead. Remove stale lock.
+        rm -f "$LOCK_DIR/pid" 2>/dev/null || true
+        rmdir "$LOCK_DIR" 2>/dev/null || true
+        continue  # retry mkdir immediately
+      fi
+    fi
+    # No pid file = old-format lock or race. Just wait and retry.
     if [ "$(date +%s)" -ge "$deadline" ]; then
       return 1
     fi
@@ -129,6 +145,7 @@ acquire_lock() {
 
 release_lock() {
   if [ "$LOCK_HELD" -eq 1 ]; then
+    rm -f "$LOCK_DIR/pid" 2>/dev/null || true
     rmdir "$LOCK_DIR" 2>/dev/null || true
     LOCK_HELD=0
   fi