[codex] Fix Codex stop hook index fallback

plugins/codex/hooks/common.sh

@@ -159,6 +159,22 @@ run_maintenance() {
 # --- Index process cleanup ---
 
 INDEX_PIDFILE="$MEMSEARCH_DIR/.index.pid"
+INDEX_LOCKDIR="$MEMSEARCH_DIR/.index.lock"
+
+index_is_running() {
+  if [ -f "$INDEX_PIDFILE" ]; then
+    local pid
+    pid=$(cat "$INDEX_PIDFILE" 2>/dev/null || true)
+    if [ -n "$pid" ] && kill -0 "$pid" 2>/dev/null; then
+      return 0
+    fi
+    rm -f "$INDEX_PIDFILE"
+  fi
+
+  local orphans
+  orphans=$(pgrep -f "memsearch index $MEMORY_DIR" 2>/dev/null || true)
+  [ -n "$orphans" ]
+}
 
 # Kill any previously spawned background index processes for this project.
 # Also sweeps orphaned milvus_lite processes.
@@ -200,6 +216,51 @@ kill_orphaned_index() {
 
 WATCH_PIDFILE="$MEMSEARCH_DIR/.watch.pid"
 
+watch_is_running() {
+  if [ -f "$WATCH_PIDFILE" ]; then
+    local pid
+    pid=$(cat "$WATCH_PIDFILE" 2>/dev/null || true)
+    if [ -n "$pid" ] && kill -0 "$pid" 2>/dev/null; then
+      return 0
+    fi
+    rm -f "$WATCH_PIDFILE"
+  fi
+
+  local orphans
+  orphans=$(pgrep -f "memsearch watch $MEMORY_DIR" 2>/dev/null || true)
+  [ -n "$orphans" ]
+}
+
+start_background_index() {
+  if [ "${MEMSEARCH_NO_WATCH:-}" = "1" ]; then
+    return 0
+  fi
+  if ! memsearch_available; then
+    return 0
+  fi
+  ensure_memory_dir
+
+  # The watch process is responsible for indexing new stop-hook memories.
+  # Only fall back to a one-at-a-time background index when no watch is alive.
+  if watch_is_running; then
+    return 0
+  fi
+  if index_is_running; then
+    return 0
+  fi
+
+  if [ -d "$INDEX_LOCKDIR" ]; then
+    rmdir "$INDEX_LOCKDIR" 2>/dev/null || return 0
+  fi
+  mkdir "$INDEX_LOCKDIR" 2>/dev/null || return 0
+
+  (
+    trap 'rm -rf "$INDEX_LOCKDIR" "$INDEX_PIDFILE" 2>/dev/null || true' EXIT
+    run_memsearch index "$MEMORY_DIR" >/dev/null
+  ) </dev/null >/dev/null 2>&1 &
+  echo $! > "$INDEX_PIDFILE"
+}
+
 # Kill a process and its entire process group to avoid orphans
 _kill_tree() {
   local pid="$1"

plugins/codex/hooks/stop.sh

@@ -197,8 +197,7 @@ ${CONTENT}"
   local _uri
   _uri="${MILVUS_URI:-$(_memsearch config get milvus.uri 2>/dev/null || echo "")}"
   if [[ "$_uri" == http* ]] || [[ "$_uri" == tcp* ]]; then
-    kill_orphaned_index
-    run_memsearch index "$MEMORY_DIR" >/dev/null
+    start_background_index
   fi
 
   run_maintenance
@@ -339,7 +338,7 @@ if [ ${#CONTENT} -gt "$MAX_CONTENT_CHARS" ]; then
   CONTENT="$(printf '%s' "$CONTENT" | _truncate_chars "$MAX_CONTENT_CHARS")...(truncated)"
 fi
 
-WORK_FILE="$(mktemp "${TMPDIR:-/tmp}/memsearch-stop.XXXXXX.json")"
+WORK_FILE="$(mktemp "${TMPDIR:-/tmp}/memsearch-stop.XXXXXX")"
 python3 - "$WORK_FILE" "$NOW" "$MEMORY_FILE" "$SESSION_ID" "$TRANSCRIPT_PATH" "$CONTENT" "$USER_QUESTION" "$LAST_MSG" <<'PY'
 from pathlib import Path
 import json

tests/test_codex_stop_hook_worker.py

@@ -0,0 +1,107 @@
+from __future__ import annotations
+
+import os
+import signal
+import subprocess
+from contextlib import suppress
+from pathlib import Path
+
+COMMON = Path("plugins/codex/hooks/common.sh")
+STOP = Path("plugins/codex/hooks/stop.sh")
+
+
+def _write_fake_memsearch(fake_bin: Path) -> None:
+    fake_memsearch = fake_bin / "memsearch"
+    fake_memsearch.write_text(
+        """#!/usr/bin/env bash
+set -euo pipefail
+if [ "${1:-}" = "config" ] && [ "${2:-}" = "get" ]; then
+  case "${3:-}" in
+    milvus.uri) echo "http://localhost:19530" ;;
+    *) echo "" ;;
+  esac
+  exit 0
+fi
+if [ "${1:-}" = "index" ]; then
+  echo "$$ $*" >> "$MEMSEARCH_FAKE_INDEX_LOG"
+  sleep 5
+  exit 0
+fi
+exit 0
+""",
+        encoding="utf-8",
+    )
+    fake_memsearch.chmod(0o755)
+
+
+def _run_common_function(tmp_path: Path, function_body: str, log_file: Path) -> subprocess.CompletedProcess[str]:
+    project = tmp_path / "project"
+    project.mkdir()
+    fake_bin = tmp_path / "bin"
+    fake_bin.mkdir()
+    _write_fake_memsearch(fake_bin)
+
+    script = f"""
+set -euo pipefail
+SCRIPT_DIR="{Path("plugins/codex/hooks").resolve()}"
+source "{COMMON.resolve()}"
+{function_body}
+"""
+    env = {
+        **os.environ,
+        "HOME": str(tmp_path / "home"),
+        "MEMSEARCH_PROJECT_DIR": str(project),
+        "MEMSEARCH_SKIP_HOOK_STDIN": "1",
+        "MEMSEARCH_FAKE_INDEX_LOG": str(log_file),
+        "MILVUS_URI": "http://localhost:19530",
+        "PATH": f"{fake_bin}:/usr/bin:/bin:/usr/sbin:/sbin",
+    }
+    return subprocess.run(["bash", "-c", script], check=True, capture_output=True, text=True, env=env)
+
+
+def test_stop_hook_uses_suffix_safe_mktemp_template() -> None:
+    source = STOP.read_text(encoding="utf-8")
+
+    assert "memsearch-stop.XXXXXX.json" not in source
+    assert 'mktemp "${TMPDIR:-/tmp}/memsearch-stop.XXXXXX"' in source
+
+
+def test_background_index_is_singleton_when_watch_is_missing(tmp_path: Path) -> None:
+    log_file = tmp_path / "index.log"
+    result = _run_common_function(
+        tmp_path,
+        """
+start_background_index
+start_background_index
+for _ in 1 2 3 4 5 6 7 8 9 10; do
+  [ -s "$MEMSEARCH_FAKE_INDEX_LOG" ] && break
+  sleep 0.1
+done
+cat "$INDEX_PIDFILE"
+""",
+        log_file,
+    )
+
+    pid = int(result.stdout.strip())
+    try:
+        lines = log_file.read_text(encoding="utf-8").splitlines()
+        assert len(lines) == 1
+    finally:
+        with suppress(ProcessLookupError):
+            os.kill(pid, signal.SIGTERM)
+
+
+def test_background_index_skips_when_watch_pid_is_alive(tmp_path: Path) -> None:
+    log_file = tmp_path / "index.log"
+    _run_common_function(
+        tmp_path,
+        """
+ensure_memory_dir
+echo "$$" > "$WATCH_PIDFILE"
+start_background_index
+sleep 0.2
+""",
+        log_file,
+    )
+
+    assert not log_file.exists()