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Subject: |
Emacs fails to respect the intent in `C-u C-u C-x C-s' of making a backup |
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Date: |
Sun, 28 Jun 2009 14:13:16 -0400 |
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User-agent: |
IMAIL/1.21; Edwin/3.116; MIT-Scheme/7.7.90.+ |
Often, when saving a file, I want to make a backup. The only way I
know to express this intent is `C-u C-u C-x C-s'. When I type `C-u
C-u C-x C-s', I mean to tell Emacs: `I want you to make a backup and
then save this file.' The documentation for the `save-buffer' command
says:
Prefixed by two C-u's,
unconditionally makes the previous version into a backup file.
^^^^^^^^^^^^^^^
Unfortunately, Emacs fails to respect my intent in many circumstances.
First, I set `version-control' to t in order to keep numbered backups.
Then in order to make backups in directories such as /tmp, I set
`backup-enable-predicate' to be a function that always returns t.
Next, in order to make backups when `vc' is involved, I set
`vc-make-backup-files' to t, which confused me because it didn't take
effect immediately -- I had to reload all my buffers before it did.
This is because some vc hook set another variable, `backup-inhibited',
when I first loaded those buffers.
There are plenty of other documented ways for arbitrary modes to
interfere with my intent when I type `C-u C-u' -- there are several
hooks that are run during `save-buffer' before `backup-buffer' and
conditions under which backups will be made. This contradicts the
documentation of `save-buffer' which explicitly says that `C-u C-u'
means a backup will be made *unconditionally*. I don't mind that
there may be various heuristics for choosing whether to make a backup
file when the user has not indicated a preference either way (by
typing `C-u 0' or `C-u C-u' or whatnot), but it is very frustrating
when the documentation says `unconditionally' and the implementation
has many documented ways to interfere and add conditions. Of course,
the documentation could simply omit the word `unconditionally', but I
don't want that either -- I want it really to be unconditional (as far
as the documented hooks in Emacs go; of course someone could redefine
`save-buffer', but it's the documented hooks and conditions such as
`backup-inhibited' that bother me).
I am using
GNU Emacs 22.2.1 (i386-apple-darwin8.11.1, GTK+ Version 2.10.13) of 2008-07-06
on Oberon.local.
In my .emacs file, relevant to backups, I have
(defun always-backup (filename) filename t)
(setq-default backup-enable-predicate 'always-backup)
(setq-default version-control t)
(setq-default vc-make-backup-files t)
(setq-default backup-inhibited nil)
(setq-default make-backup-files t)
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--- Begin Message ---
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Subject: |
Re: bug#3702: Emacs fails to respect the intent in `C-u C-u C-x C-s' of making a backup |
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Date: |
Sat, 09 Jul 2016 14:19:08 +0300 |
> From: Andrew Hyatt <address@hidden>
> Date: Sat, 25 Jun 2016 23:22:42 -0400
>
>
> Eli Zaretskii <address@hidden> writes:
>
> >> From: Andrew Hyatt <address@hidden>
> >> Date: Fri, 17 Jun 2016 23:37:28 -0400
> >> Cc: address@hidden
> >>
> >>
> >> Sorry for the late reply on this one. This problem still exists in
> >> Emacs 25. I agree that the current behavior doesn't match up with the
> >> documentation.
> >>
> >> This probably is fixable by adding another free variable set by
> >> save-buffer and read in various functions, but there's a lot of those
> >> kind of variables already - the logic here, IMHO, could use a rewrite to
> >> make the interactions clear. Maybe someone familiar with this code
> >> might give their opinion.
> >
> > It sounds like this report boils down to interpreting the single word
> > "unconditionally" in the doc string of save-buffer. All the rest is
> > actually a request for a feature that never existed in Emacs. (FWIW,
> > I don't object to adding such a feature, if someone submits patches to
> > that effect.)
>
> Maybe the solution then is just to change the wording in the
> documentation? But it might take someone who is very familiar with the
> various exceptions to craft the new wording.
OK, I modified the doc string to the above effect on the emacs-25
branch, and I'm marking this bug done.
Thanks.
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