Subject: Re: bug#54636: dired fails to update subdirs when files are created/deleted/renamed

From: Tassilo Horn <[email-masked]>
Date: Wed, 30 Mar 2022 18:29:29 +0200

Tassilo Horn <[email-masked]> writes:

> I think my patch is valid but now I think I should just create a
> separate function dired-buffers-for-cleanup and use that from
> dired-clean-up-after-deletion (or just collect the buffers in that
> function) and remove the SUBDIRS argument from dired-buffers-for-dir
> as it changes its logic too drastically.
>
> I'll prepare a patch in that direction later.

Here it is:

diff --git a/lisp/dired.el b/lisp/dired.el
index 75dcd33e67..89b81ca0db 100644
--- a/lisp/dired.el
+++ b/lisp/dired.el
@@ -2870,12 +2870,10 @@ dired-copy-filename-as-kill
 
 ;;; Keeping Dired buffers in sync with the filesystem and with each other
 
-(defun dired-buffers-for-dir (dir &optional file subdirs)
+(defun dired-buffers-for-dir (dir &optional file)
   "Return a list of buffers for DIR (top level or in-situ subdir).
 If FILE is non-nil, include only those whose wildcard pattern (if any)
 matches FILE.
-If SUBDIRS is non-nil, also include the dired buffers of
-directories below DIR.
 The list is in reverse order of buffer creation, most recent last.
 As a side effect, killed dired buffers for DIR are removed from
 `dired-buffers'."
@@ -2889,8 +2887,7 @@ dired-buffers-for-dir
 	(setq dired-buffers (delq elt dired-buffers)))
        ((dired-in-this-tree-p dir (car elt))
 	(with-current-buffer buf
-          (when (and (or subdirs
-                         (assoc dir dired-subdir-alist))
+          (when (and (assoc dir dired-subdir-alist)
 	             (or (null file)
 		         (if (stringp dired-directory)
 		             (let ((wildcards (file-name-nondirectory
@@ -2903,6 +2900,22 @@ dired-buffers-for-dir
             (setq result (cons buf result)))))))
     result))
 
+(defun dired-buffers-for-dir-or-subdir (dir)
+  "Return a list of buffers for DIR or a subdirectory thereof.
+As a side effect, killed dired buffers for DIR are removed from
+`dired-buffers'."
+  (setq dir (file-name-as-directory dir))
+  (let (result buf)
+    (dolist (elt dired-buffers)
+      (setq buf (cdr elt))
+      (cond
+       ((null (buffer-name buf))
+	;; Buffer is killed - clean up:
+	(setq dired-buffers (delq elt dired-buffers)))
+       ((dired-in-this-tree-p (car elt) dir)
+        (setq result (cons buf result)))))
+    result))
+
 (defun dired-glob-regexp (pattern)
   "Convert glob-pattern PATTERN to a regular expression."
   (let ((matched-in-pattern 0)  ;; How many chars of PATTERN we've handled.
@@ -3479,15 +3492,16 @@ dired-clean-up-after-deletion
                                      (file-name-nondirectory fn))))
                (not dired-clean-confirm-killing-deleted-buffers))
            (kill-buffer buf)))
-    (let ((buf-list (dired-buffers-for-dir (expand-file-name fn)
-                                           nil 'subdirs)))
+    (let ((buf-list (dired-buffers-for-dir-or-subdir
+                     (expand-file-name fn))))
       (and buf-list
            (or (and dired-clean-confirm-killing-deleted-buffers
                     (y-or-n-p
                      (format
-                      (ngettext "Kill Dired buffer of %s, too? "
-                                "Kill Dired buffers of %s, too? "
-                                (length buf-list))
+                      (ngettext
+                       "Kill Dired buffer of %s, too? "
+                       "Kill Dired buffers of %s and its sub-directories, too? "
+                       (length buf-list))
                       (file-name-nondirectory
                        ;; FN may end in a / if `dired-listing-switches'
                        ;; contains -p, so we need to strip that

I think that's a better approach than changing dired-buffers-for-dir
which I shouldn't have done in the first place.

Bye,
Tassilo