GNU bug report logs - #21443
24.5; etags' complete-tag changes the global value of tags-file-name

Previous Next

Full log

View this message in rfc822 format

From: Dmitry Gutov <dgutov <at> yandex.ru>
To: Eli Zaretskii <eliz <at> gnu.org>, HGY <mohu3g <at> 163.com>
Cc: 21443 <at> debbugs.gnu.org
Subject: bug#21443: 24.5; etags' complete-tag changes the global value of tags-file-name
Date: Tue, 24 Nov 2015 00:03:12 +0200

On 09/11/2015 09:57 AM, Eli Zaretskii wrote:

> You can't, currently.  You need to invoke visit-tags-table manually,
> with a prefix argument, before the mini-buffer completion.  This is
> how the code was designed.

Unfortunately, this is also broken: you can C-u M-x visit-tags-table, 
and it will set the local value of tags-file-name, but as soon as you 
M-x find-tag, it changes the global value of tags-file-name as well, to 
the last element in tags-table-list.

Apparently because the lambda in tags-lazy-completion-table calls 
visit-tags-table-buffer at least twice, and the latter function modifies 
tags-file-name, _and_ changes the current buffer (and when called the 
second time, it changes tags-file-name in the tags table buffer, thus 
changing the global value).

And I can't simply wrap most of the second half of 
visit-tags-table-buffer in a with-current-buffer, because some code 
assumes that the buffer does indeed change. Otherwise, the value of 
tags-completion-table-function is nil (tags-completion-table calls it 
after calling visit-tags-table-buffer).

Modifications of tags-file-name are also numerous, so changing a couple 
of setq to setq-local inside visit-tags-table-buffer doesn't do the 
trick either.

At this point I'm leaving this to someone else who's more motivated. But 
we'll likely already migrate to e.g. GNU Global before that happens.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.