win: fix watch loop logic (#5013)

Refs: https://github.com/nodejs/node/issues/61398

src/win/fs-event.c

@@ -433,6 +433,7 @@ void uv__process_fs_event_req(uv_loop_t* loop, uv_req_t* req,
   WCHAR* filenamew = NULL;
   WCHAR* long_filenamew = NULL;
   DWORD offset = 0;
+  int dir_event_detected = 0;
 
   assert(req->type == UV_FS_EVENT_REQ);
   assert(handle->req_pending);
@@ -459,6 +460,10 @@ void uv__process_fs_event_req(uv_loop_t* loop, uv_req_t* req,
         assert(!filenamew);
         assert(!long_filenamew);
 
+        if (file_info->FileNameLength == 0) {
+          dir_event_detected = 1;
+        }
+
         /*
          * Fire the event only if we were asked to watch a directory,
          * or if the filename filter matches.
@@ -587,6 +592,7 @@ void uv__process_fs_event_req(uv_loop_t* loop, uv_req_t* req,
                                      sizeof(info)) &&
         info.Directory &&
         info.DeletePending) {
+      dir_event_detected = 1;
       uv__convert_utf16_to_utf8(handle->dirw, -1, &filename);
       handle->cb(handle, filename, UV_RENAME, 0);
       uv__free(filename);
@@ -599,6 +605,26 @@ void uv__process_fs_event_req(uv_loop_t* loop, uv_req_t* req,
   if (handle->flags & UV_HANDLE_CLOSING) {
     uv__want_endgame(loop, (uv_handle_t*)handle);
   } else if (uv__is_active(handle)) {
+    /*
+     * Check if the handle has become a zombie pointing to \$Extend\$Deleted\.
+     * Only perform the check if we detected an event on the directory, which
+     * may indicate deletion.
+     */
+    if (dir_event_detected) {
+      WCHAR path_buf[MAX_PATH];
+      DWORD path_len = GetFinalPathNameByHandleW(handle->dir_handle,
+                                                 path_buf,
+                                                 ARRAY_SIZE(path_buf),
+                                                 FILE_NAME_NORMALIZED | VOLUME_NAME_NONE);
+
+      if (path_len > 0 && path_len < ARRAY_SIZE(path_buf)) {
+        if (wcsstr(path_buf, L"\\$Extend\\$Deleted\\") != NULL) {
+          handle->cb(handle, NULL, 0, UV_ENOENT);
+          return;
+        }
+      }
+    }
+
     uv__fs_event_queue_readdirchanges(loop, handle);
   }
 }

test/test-fs-event.c

@@ -519,6 +519,51 @@ TEST_IMPL(fs_event_watch_delete_dir) {
   return 0;
 }
 
+#ifdef _WIN32
+static int fs_event_cb_del_dir_perm_got_enoent;
+
+static void fs_event_cb_del_dir_perm(uv_fs_event_t* handle,
+                                     const char* filename,
+                                     int events,
+                                     int status) {
+  if (status == UV_ENOENT) {
+    fs_event_cb_del_dir_perm_got_enoent = 1;
+    uv_close((uv_handle_t*)handle, close_cb);
+  }
+}
+
+TEST_IMPL(fs_event_watch_delete_dir_win) {
+  uv_loop_t* loop = uv_default_loop();
+  int r;
+
+  /* Setup */
+  fs_event_cb_del_dir_perm_got_enoent = 0;
+  fs_event_unlink_files(NULL);
+  delete_dir("watch_del_dir/");
+  create_dir("watch_del_dir");
+
+  r = uv_fs_event_init(loop, &fs_event);
+  ASSERT_OK(r);
+  r = uv_fs_event_start(&fs_event, fs_event_cb_del_dir_perm, "watch_del_dir", 0);
+  ASSERT_OK(r);
+  r = uv_timer_init(loop, &timer);
+  ASSERT_OK(r);
+  r = uv_timer_start(&timer, fs_event_del_dir, 100, 0);
+  ASSERT_OK(r);
+
+  uv_run(loop, UV_RUN_DEFAULT);
+
+  ASSERT_EQ(1, fs_event_cb_del_dir_perm_got_enoent);
+  ASSERT_EQ(2, close_cb_called);
+
+  /* Cleanup */
+  fs_event_unlink_files(NULL);
+
+  MAKE_VALGRIND_HAPPY(loop);
+  return 0;
+}
+#endif
+
 
 TEST_IMPL(fs_event_watch_dir_recursive) {
 #if defined(__APPLE__) && defined(__TSAN__)

test/test-list.h

@@ -410,6 +410,9 @@ TEST_FS_DECLARE   (fs_read_bufs)
 TEST_FS_DECLARE   (fs_read_file_eof)
 TEST_DECLARE   (fs_event_watch_dir)
 TEST_DECLARE   (fs_event_watch_delete_dir)
+#ifdef _WIN32
+TEST_DECLARE   (fs_event_watch_delete_dir_win)
+#endif
 TEST_DECLARE   (fs_event_watch_dir_recursive)
 #ifdef _WIN32
 TEST_DECLARE   (fs_event_watch_dir_short_path)
@@ -1143,6 +1146,9 @@ TASK_LIST_START
   TEST_FS_ENTRY  (fs_file_open_append)
   TEST_ENTRY  (fs_event_watch_dir)
   TEST_ENTRY  (fs_event_watch_delete_dir)
+#ifdef _WIN32
+  TEST_ENTRY  (fs_event_watch_delete_dir_win)
+#endif
   TEST_ENTRY  (fs_event_watch_dir_recursive)
 #ifdef _WIN32
   TEST_ENTRY  (fs_event_watch_dir_short_path)