Subject: Re: bug#60897: 29.0.60; vc-revert fails to revert buffer

From: Juri Linkov <[email-masked]>
Date: Tue, 24 Jan 2023 19:46:51 +0200

>> >> >  (defun vc-resynch-buffer (file &optional keep noquery reset-vc-info)
>> >> >    "If FILE is currently visited, resynch its buffer."
>> >> > +  (unless (file-name-absolute-p file)
>> >> > +    (setq file (expand-file-name file (vc-root-dir))))
>> >> >    (if (string= buffer-file-name file)
>> >> >        (vc-resynch-window file keep noquery reset-vc-info)
>> >> >      (if (file-directory-p file)
>>
>> There is another string= call that fails inside vc-resynch-window
>> called from vc-resynch-buffer.
>
> How about replacing string= in these two cases with something smarter,
> which would expand-file-name?  Comparing file names as simple strings
> is wrought with trouble anyway.

This works as well:

diff --git a/lisp/vc/vc-dispatcher.el b/lisp/vc/vc-dispatcher.el
index e1a3eff448d..8a0cdef4726 100644
--- a/lisp/vc/vc-dispatcher.el
+++ b/lisp/vc/vc-dispatcher.el
@@ -608,7 +608,7 @@ vc-resynch-window
 difference between the buffer and the file is due to
 modifications by the dispatcher client code, rather than user
 editing!"
-  (and (string= buffer-file-name file)
+  (and (string-prefix-p file buffer-file-name)
        (if keep
 	   (when (file-exists-p file)
 	     (when reset-vc-info
@@ -643,7 +643,7 @@ vc-resynch-buffers-in-directory
 
 (defun vc-resynch-buffer (file &optional keep noquery reset-vc-info)
   "If FILE is currently visited, resynch its buffer."
-  (if (string= buffer-file-name file)
+  (if (string-prefix-p file buffer-file-name)
       (vc-resynch-window file keep noquery reset-vc-info)
     (if (file-directory-p file)
 	(vc-resynch-buffers-in-directory file keep noquery reset-vc-info)