Improve handling of pending file notification events

* lisp/filenotify.el (file-notify--check-pending-rename): New defun.
(file-notify--handle-event): Use it.  Start a timer checking
pending events.  (Bug#81531)

* test/lisp/filenotify-tests.el (file-notify--test-with-actions):
Read pending event.
(file-notify-test05-file-validity, file-notify-test12-symlinks):
Adapt tests.
(file-notify-test13-unmount): Rename.

lisp/filenotify.el

@@ -243,6 +243,16 @@ It is nil or a `file-notify--rename' defstruct where the cookie can be nil.")
                    (list desc action file file1)
                  (list desc action file))))))
 
+(defun file-notify--check-pending-rename ()
+  "Fire a `deleted' event from a pending `rename'."
+  (when file-notify--pending-rename
+    (file-notify--call-handler
+     (file-notify--rename-watch file-notify--pending-rename)
+     (file-notify--rename-desc file-notify--pending-rename)
+     'deleted
+     (file-notify--rename-from-file file-notify--pending-rename)
+     (setq file-notify--pending-rename nil))))
+
 (defun file-notify--handle-event (desc actions file file1-or-cookie)
   "Handle an event returned from file notification.
 DESC is the back-end descriptor.  ACTIONS is a list of:
@@ -290,7 +300,8 @@ DESC is the back-end descriptor.  ACTIONS is a list of:
            ((eq action 'renamed-from)
             (setq file-notify--pending-rename
                   (file-notify--rename-make watch desc file file1-or-cookie)
-                  action nil))
+                  action nil)
+	    (run-at-time 0.1 nil #'file-notify--check-pending-rename))
            ;; Look for pending event.
            ((eq action 'renamed-to)
             (if file-notify--pending-rename
@@ -323,14 +334,7 @@ DESC is the back-end descriptor.  ACTIONS is a list of:
                        (string-equal
                         file (file-notify--watch-absolute-filename watch))))
           ;; Fire pending `renamed-from' event.
-          (when file-notify--pending-rename
+          (file-notify--check-pending-rename)
-            (file-notify--call-handler
-             (file-notify--rename-watch file-notify--pending-rename)
-             (file-notify--rename-desc file-notify--pending-rename)
-             'deleted
-             (file-notify--rename-from-file file-notify--pending-rename)
-             nil)
-            (setq file-notify--pending-rename nil))
           (setq actions nil)
           ;; Make sure this is the last time the callback was invoked.
           (when (eq action 'stopped)

test/lisp/filenotify-tests.el

@@ -641,6 +641,8 @@ delivered."
       (* (ceiling max-length 100) (file-notify--test-timeout))
       (or (= max-length (length file-notify--test-events))
           (memq 'stopped (file-notify--test-event-actions))))
+     ;; Read possible pending event.
+     (file-notify--test-wait-event)
      ;; Check the result sequence just to make sure that all actions
      ;; are as expected.
      (dolist (result file-notify--test-results)
@@ -1070,7 +1072,6 @@ delivered."
      (write-region "another text" nil file-notify--test-tmpfile nil 'no-message)
      (file-notify--test-wait-event)
      (delete-file file-notify--test-tmpfile))
-   (file-notify--test-wait-event)
    ;; After deleting the file, the descriptor is not valid anymore.
    (should-not (file-notify-valid-p file-notify--test-desc))
    (file-notify-rm-watch file-notify--test-desc)
@@ -1693,18 +1694,13 @@ the file watch."
           (t '(attribute-changed)))
        (set-file-times file-notify--test-tmpfile '(0 0) 'nofollow))
 
-     ;; Deleting the target should not raise any event.
+     ;; Deleting the target should remove the watch.
-     (file-notify--test-with-actions nil
+     (file-notify--test-with-actions '(deleted stopped)
        (delete-file file-notify--test-tmpfile1)
        (delete-file file-notify--test-tmpfile))
-     ;; Sanity check.
+     (file-notify-rm-watch file-notify--test-desc)
-     (file-notify--test-wait-for-events
-      (file-notify--test-timeout)
-      (not (input-pending-p)))
-     (should-not file-notify--test-events)
 
      ;; The environment shall be cleaned up.
-     (file-notify-rm-watch file-notify--test-desc)
      (file-notify--test-cleanup-p)))
 
   (with-file-notify-test
@@ -1724,21 +1720,38 @@ the file watch."
        (should (file-notify-valid-p file-notify--test-desc))
 
        ;; None of the actions on a file in the symlinked directory
-       ;; will be reported.
+       ;; will be reported, except ...
-       (file-notify--test-with-actions nil
+       (file-notify--test-with-actions
+           (cond
+            ;; GKqueueFileMonitor reports deleted only.
+            ((eq (file-notify--test-monitor) 'GKqueueFileMonitor)
+             '(deleted))
+            ;; GInotifyFileMonitor still reports changes.
+            ((and (string-equal (file-notify--test-library) "gio")
+	          (eq (file-notify--test-monitor) 'GInotifyFileMonitor))
+	     '(changed changed attribute-changed changed changed
+               attribute-changed attribute-changed attribute-changed
+               attribute-changed attribute-changed deleted))
+            ((and (string-equal (file-notify--test-library) "gfilenotify")
+	          (eq (file-notify--test-monitor) 'GInotifyFileMonitor))
+             '(changed changed changed changed attribute-changed
+               attribute-changed attribute-changed attribute-changed deleted))
+            (t nil))
          (write-region "another text" nil tmpfile nil 'no-message)
+         (file-notify--test-wait-event)
          (write-region "another text" nil tmpfile1 nil 'no-message)
+         (file-notify--test-wait-event)
          (set-file-times tmpfile '(0 0))
+         (file-notify--test-wait-event)
          (set-file-times tmpfile '(0 0) 'nofollow)
+         (file-notify--test-wait-event)
          (set-file-times tmpfile1 '(0 0))
+         (file-notify--test-wait-event)
          (set-file-times tmpfile1 '(0 0) 'nofollow)
+         (file-notify--test-wait-event)
          (delete-file tmpfile)
+         (file-notify--test-wait-event)
          (delete-file tmpfile1))
-       ;; Sanity check.
-       (file-notify--test-wait-for-events
-        (file-notify--test-timeout)
-        (not (input-pending-p)))
-       (should-not file-notify--test-events)
 
        ;; The environment shall be cleaned up.
        (delete-directory file-notify--test-tmpdir 'recursive)
@@ -1748,7 +1761,7 @@ the file watch."
 (file-notify--deftest-remote file-notify-test12-symlinks
   "Check `file-notify-test12-symlinks' for remote files.")
 
-(ert-deftest file-notify-test12-unmount ()
+(ert-deftest file-notify-test13-unmount ()
   "Check that file notification stop after unmounting the filesystem."
   :tags '(:expensive-test)
   (skip-unless (file-notify--test-local-enabled))
@@ -1799,8 +1812,8 @@ the file watch."
    ;; The environment shall be cleaned up.
    (file-notify--test-cleanup-p)))
 
-(file-notify--deftest-remote file-notify-test12-unmount
+(file-notify--deftest-remote file-notify-test13-unmount
-  "Check `file-notify-test12-unmount' for remote files.")
+  "Check `file-notify-test13-unmount' for remote files.")
 
 (defun file-notify-test-all (&optional interactive)
   "Run all tests for \\[file-notify]."