bug#74881: 31.0.50; [PATCH] * lisp/vc/ediff-util.el: Remove temp files on kill-emacs

bug#74881: 31.0.50; [PATCH] * lisp/vc/ediff-util.el: Remove temp files on kill-emacs

[Lin Sun]

[-- Attachment #1: Type: text/plain, Size: 681 bytes --]

The ediff lefts temporary files "/tmp/fineDiff*" when kill emacs during an ediff comparing.

Reproducing steps:

1. echo 0 > /tmp/0; echo 1 > /tmp/1

2. emacs -nw -q -f ediff-files-command /tmp/0 /tmp/1 

on the ediff control buffer, press "n" to move to first difference; there should have two temp files like /tmp/fineDiffA* and /tmp/fineDiffB* were generated by ediff, stay on the ediff buffer (do not press "q" to quit the ediff session). then

3. Press "C-x C-c" or kill-emacs to quit the emacs directly.

Then two temp files /tmp/fineDiff* were left there.

This patch will make sure the temp files be removed when kill-emacs without quitting the ediff session.

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-lisp-vc-ediff-util.el-Remove-temp-files-on-kill-emac.patch --]
[-- Type: text/x-patch; name="0001-lisp-vc-ediff-util.el-Remove-temp-files-on-kill-emac.patch", Size: 1195 bytes --]

From dee9750144df6cdd827397f3d97e74f56e25e1fa Mon Sep 17 00:00:00 2001
From: Lin Sun <sunlin7@hotmail.com>
Date: Sun, 15 Dec 2024 06:52:17 +0000
Subject: [PATCH] * lisp/vc/ediff-util.el: Remove temp files on kill-emacs

---
 lisp/vc/ediff-util.el | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lisp/vc/ediff-util.el b/lisp/vc/ediff-util.el
index 6038f3eae30..fb47b3f7563 100644
--- a/lisp/vc/ediff-util.el
+++ b/lisp/vc/ediff-util.el
@@ -213,6 +213,12 @@ ediff-setup-keymap
   (fset 'ediff-mode-map ediff-mode-map)
   (run-hooks 'ediff-keymap-setup-hook))
 
+(defun ediff--delete-temp-files-on-kill-emacs ()
+  "Delete the temp-files associated with the ediff buffers."
+  (dolist (b (buffer-list))
+    (with-current-buffer b
+      (when (eq major-mode 'ediff-mode)
+        (ediff-delete-temp-files)))))
 
 ;;; Setup functions
 
@@ -488,6 +494,7 @@ ediff-setup
       (if (ediff-buffer-live-p ediff-meta-buffer)
 	  (ediff-update-meta-buffer
 	   ediff-meta-buffer nil ediff-meta-session-number))
+      (add-hook 'kill-emacs-hook #'ediff--delete-temp-files-on-kill-emacs)
       (run-hooks 'ediff-startup-hook)
       ) ; eval in control-buffer
     control-buffer))
-- 
2.34.1

bug#74881: 31.0.50; [PATCH] * lisp/vc/ediff-util.el: Remove temp files on kill-emacs

[Eli Zaretskii]

> From: Lin Sun <sunlin7@hotmail.com>
> Date: Sun, 15 Dec 2024 05:59:40 +0000
> 
> @@ -488,6 +494,7 @@ ediff-setup
>        (if (ediff-buffer-live-p ediff-meta-buffer)
>  	  (ediff-update-meta-buffer
>  	   ediff-meta-buffer nil ediff-meta-session-number))
> +      (add-hook 'kill-emacs-hook #'ediff--delete-temp-files-on-kill-emacs)
>        (run-hooks 'ediff-startup-hook)
>        ) ; eval in control-buffer
>      control-buffer))

This should be carefully programmed to avoid preventing Emacs from
exiting due to some problem.  If ediff-delete-temp-files or one of the
functions it calls can signal an error, it should be wrapped by
condition-case, and if it or one of its callees can try interacting
with the user, we should use kill-emacs-query-functions instead.

Alternatively, we could end the Ediff session when Emacs is killed.

Bottom line: this is a minor cleanup feature, so we should be very
careful not to cause any regressions and problems just because we want
to exit more cleanly.  (On most systems, files in /tmp are routinely
deleted by system's cleanup processes anyway.)

Thanks.