--- Begin Message ---
Subject: |
29.0.50; Buffer-menu-visit-tags-table disrupts non-tags buffers |
Date: |
Wed, 23 Feb 2022 16:37:11 -0500 |
In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.20, cairo
version 1.16.0)
of 2022-02-19 built on orion
Repository revision: 563bb08c5998f82e034a0aa1b48dce29fb9bc375
Repository branch: rgr-smtpmail-env-from
Windowing system distributor 'The X.Org Foundation', version 11.0.12003000
System Description: openSUSE Leap 15.3
Configured using:
'configure --with-dbus=no --with-gsettings=no --with-gif=ifavailable
--with-tiff=no --with-gnutls=yes --with-gconf=no'
Configured features:
ACL CAIRO FREETYPE GIF GLIB GMP GNUTLS HARFBUZZ JPEG LIBSELINUX LIBXML2
MODULES NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS
TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM GTK3 ZLIB
To reproduce:
In master ecaedf2117cb015ad4028e4d6fc7058608c98096:
1. "emacs -Q &"
2. Visit pretty much any random file that is NOT a tags file; for
this purpose, lisp/abbrev.el from the source tree will do nicely.
3. Type "C-x C-b" to get the "*Buffer List*" window to appear.
4. Type "C-x o" to move the to the buffer list, then move to the
abbrev.el line, and type "t" to invoke Buffer-menu-visit-tags-table on
it (which I seem to do accidentally more often than I care to admit).
This produces the error message:
user-error: File /scratch/rogers/emacs/lisp/abbrev.el is not a valid
tags table
but the abbrev.el buffer is left in tags-table-mode, and any undo
information is thrown away.
The attached patch addresses the problem in a straightforward way by
making Buffer-menu-visit-tags-table prompt the user for buffers not
already in tags-table-mode.
The real problem is that visit-tags-table assumes that the user knows
what they're doing, and makes these irreversible changes before being
sure of having a valid tags table. That would be a harder thing to fix,
though -- and might not deal as well with my buffer-menu typos. ;-}
-- Bob Rogers
http://www.rgrjr.com/
From 05d2d1855cddc8d5c310d718c07d91ae861b8436 Mon Sep 17 00:00:00 2001
From: Bob Rogers <rogers@rgrjr.com>
Date: Wed, 23 Feb 2022 16:23:17 -0500
Subject: [PATCH] Make Buffer-menu-visit-tags-table more circumspect
* lisp/buff-menu.el:
+ (Buffer-menu-visit-tags-table): Ask before visit-tags-table on a
buffer not already in tags-table-mode, lest it destroy state.
---
lisp/buff-menu.el | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/lisp/buff-menu.el b/lisp/buff-menu.el
index 50c2c155ca..0bed539008 100644
--- a/lisp/buff-menu.el
+++ b/lisp/buff-menu.el
@@ -530,10 +530,21 @@ Buffer-menu-multi-occur
(defun Buffer-menu-visit-tags-table ()
"Visit the tags table in the buffer on this line. See `visit-tags-table'."
(interactive nil Buffer-menu-mode)
- (let ((file (buffer-file-name (Buffer-menu-buffer t))))
- (if file
- (visit-tags-table file)
- (error "Specified buffer has no file"))))
+ (let* ((buffer (Buffer-menu-buffer t))
+ (file (buffer-file-name buffer)))
+ (or file
+ (error "Specified buffer has no file"))
+ ;; Ensure that it's really a tags file buffer (or the user at
+ ;; least believes it should be). Otherwise, visit-tags-table will
+ ;; change the mode and discard any undo information.
+ (if (not (or (eq (with-current-buffer buffer
+ major-mode)
+ 'tags-table-mode)
+ (yes-or-no-p
+ (format "%s is not a tags table; visit as such anyway? "
+ buffer))))
+ (error "Aborted."))
+ (visit-tags-table file)))
(defun Buffer-menu-1-window ()
"Select this line's buffer, alone, in full frame."
--
2.34.1
--- End Message ---
--- Begin Message ---
Subject: |
Re: bug#54133: 29.0.50; Buffer-menu-visit-tags-table disrupts non-tags buffers |
Date: |
Thu, 24 Feb 2022 22:00:30 +0200 |
> From: Bob Rogers <rogers@rgrjr.com>
> Date: Thu, 24 Feb 2022 13:02:40 -0500
> CC: 54133@debbugs.gnu.org
>
> Maybe we should have a more thorough implementation in
> etags-verify-tags-table, then. But that function's purpose is to do
> what we need here.
>
> That would require disentangling detection and initialization. Which
> shouldn't be all that hard; it just seemed like more work than necessary
> to scratch this particular itch.
>
> > In short, I thought checking the major mode was the better choice,
> > since the file was already present in a buffer.
>
> But what if the file is already in a buffer, but not under the right
> major-mode? E.g., what if the file was visited literally?
>
> Ah, so you mean that Buffer-menu-visit-tags-table is normally meant to
> introduce tags-table-mode in buffers not already there. I see now that
> is implied by "Visit the tags table ..." in the command documentation.
> In which case I withdraw my reservations.
Thanks, I installed the changes, and I'm marking this bug done.
> And maybe I'll have a look at cleaning up etags initialization when I
> get a chance . . .
TIA.
--- End Message ---