[PATCH] Save unmodified buffer when file has been deleted

[PATCH] Save unmodified buffer when file has been deleted

[Bastien]

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If you accidently delete the file while an unmodified buffer is visiting
it, trying to save this buffer will fail because it's unmodified.

This patch fixes this problem.

Let me know if it's okay to commit it (with a proper ChangeLog entry).

Thanks,


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diff --git a/lisp/files.el b/lisp/files.el
index 8b42eaa..029c55d 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -4309,7 +4309,11 @@ Before and after saving the buffer, this function runs
     ;; In an indirect buffer, save its base buffer instead.
     (if (buffer-base-buffer)
 	(set-buffer (buffer-base-buffer)))
-    (if (buffer-modified-p)
+    (if (or (buffer-modified-p)
+	    ;; handle the case when no modification has been made but
+	    ;; the file has been delete
+	    (and (buffer-file-name)
+		 (not (file-exists-p (buffer-file-name)))))
 	(let ((recent-save (recent-auto-save-p))
 	      setmodes)
 	  ;; If buffer has no file name, ask user for one.

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-- 
 Bastien

Re: [PATCH] Save unmodified buffer when file has been deleted

[Eli Zaretskii]

> From: Bastien <bastien.guerry@wikimedia.fr>
> Date: Fri, 11 Feb 2011 10:19:08 +0100
> 
> +    (if (or (buffer-modified-p)
> +	    ;; handle the case when no modification has been made but
> +	    ;; the file has been delete
                        ^^^^^^^^^^^^^^^
"has been deleted".  Actually, I would say "the file disappeared since
visited" or some such.

Re: [PATCH] Save unmodified buffer when file has been deleted

[Bastien]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Bastien <bastien.guerry@wikimedia.fr>
>> Date: Fri, 11 Feb 2011 10:19:08 +0100
>> 
>> +    (if (or (buffer-modified-p)
>> +	    ;; handle the case when no modification has been made but
>> +	    ;; the file has been delete
>                         ^^^^^^^^^^^^^^^
> "has been deleted".  Actually, I would say "the file disappeared since
> visited" or some such.

Yes, right.

Is that okay to commit this?  Would be my first commit from bzr, I'm
quite nervous about it :)

-- 
 Bastien

Re: [PATCH] Save unmodified buffer when file has been deleted

[Stefan Monnier]

> +	    (and (buffer-file-name)
> +		 (not (file-exists-p (buffer-file-name)))))

Please just use the buffer-file-name variable rather than the function.
Other than that, it looks like a good change (I've gotten used to
hitting SPC Backspace C-x C-s, and I also use this when I just want to
`touch' the file, so I probably won't use this feature much, tho).


        Stefan

Re: [PATCH] Save unmodified buffer when file has been deleted

[Lennart Borgman]

On Fri, Feb 11, 2011 at 3:38 PM, Stefan Monnier
<monnier@iro.umontreal.ca> wrote:
>> +         (and (buffer-file-name)
>> +              (not (file-exists-p (buffer-file-name)))))
>
> Please just use the buffer-file-name variable rather than the function.
> Other than that, it looks like a good change (I've gotten used to
> hitting SPC Backspace C-x C-s, and I also use this when I just want to
> `touch' the file, so I probably won't use this feature much, tho).

Why is the variable buffer-file-name preferred over the function?

Re: [PATCH] Save unmodified buffer when file has been deleted

[Eli Zaretskii]

> From: Bastien <bastien.guerry@wikimedia.fr>
> Cc: emacs-devel@gnu.org
> Date: Fri, 11 Feb 2011 10:48:37 +0100
> 
> Would be my first commit from bzr, I'm quite nervous about it :)

If you want, you could post the commands you think you will need here,
and ask for comments.

Re: [PATCH] Save unmodified buffer when file has been deleted

[Bastien]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> +	    (and (buffer-file-name)
>> +		 (not (file-exists-p (buffer-file-name)))))
>
> Please just use the buffer-file-name variable rather than the
> function.

Done, thanks.

> Other than that, it looks like a good change (I've gotten used to
> hitting SPC Backspace C-x C-s, and I also use this when I just want to
> `touch' the file, so I probably won't use this feature much, tho).

Well, we shouldn't get used to hit useless keystrokes :)

-- 
 Bastien

Re: [PATCH] Save unmodified buffer when file has been deleted

[Bastien]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Bastien <bastien.guerry@wikimedia.fr>
>> Cc: emacs-devel@gnu.org
>> Date: Fri, 11 Feb 2011 10:48:37 +0100
>> 
>> Would be my first commit from bzr, I'm quite nervous about it :)
>
> If you want, you could post the commands you think you will need here,
> and ask for comments.

Thanks for proposing.  I have read 

  http://www.emacswiki.org/emacs/BzrForEmacsDevs

quite carefully and I just committed the change by using a "quickfixes"
branch, as suggested on this page.  Things worked as expected.

-- 
 Bastien

Re: [PATCH] Save unmodified buffer when file has been deleted

[Eli Zaretskii]

> From: Bastien <bastien.guerry@wikimedia.fr>
> Date: Fri, 11 Feb 2011 18:56:36 +0100
> Cc: emacs-devel@gnu.org
> 
> I have read 
> 
>   http://www.emacswiki.org/emacs/BzrForEmacsDevs
> 
> quite carefully and I just committed the change by using a "quickfixes"
> branch, as suggested on this page.  Things worked as expected.

Is your "quickfixes" branch bound to the remote repository?  Or maybe
you "bzr push"ed the changes from an un-bound branch?  Because I don't
see any signs of a merge in your commit.

Re: [PATCH] Save unmodified buffer when file has been deleted

[Bastien]

Eli Zaretskii <eliz@gnu.org> writes:

> Is your "quickfixes" branch bound to the remote repository?  

Yes -- sorry I didn't mention that.  (This is the way the quickfixes
branch is set up on emacswiki instructions.)

-- 
 Bastien

Re: [PATCH] Save unmodified buffer when file has been deleted

[Eli Zaretskii]

> From: Bastien <bastien.guerry@wikimedia.fr>
> Cc: emacs-devel@gnu.org
> Date: Fri, 11 Feb 2011 20:01:00 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Is your "quickfixes" branch bound to the remote repository?  
> 
> Yes -- sorry I didn't mention that.  (This is the way the quickfixes
> branch is set up on emacswiki instructions.)

Right, I forgot that the wiki was changed to recommend that quickfixes
be also a bound branch.  (In my workflow, it isn't; it is a "task
branch".)

Re: [PATCH] Save unmodified buffer when file has been deleted

[Stefan Monnier]

>>> +         (and (buffer-file-name)
>>> +              (not (file-exists-p (buffer-file-name)))))
>> 
>> Please just use the buffer-file-name variable rather than the function.
>> Other than that, it looks like a good change (I've gotten used to
>> hitting SPC Backspace C-x C-s, and I also use this when I just want to
>> `touch' the file, so I probably won't use this feature much, tho).

> Why is the variable buffer-file-name preferred over the function?

Because IMHO the function is just a historical accident.
And the variable is slightly more efficient.


        Stefan