save-buffer when directory doesn't exist

save-buffer when directory doesn't exist

[martin rudalics]

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Assume I modify *scratch* and try to `save-buffer' it as ".../bar/foo".
(I know `write-file' should be used for this purpose but `save-buffer'
offers the service as well.)  Assume further, I mistype the name as
".../baz/foo" where the subdirectory "baz" does not exist.  Emacs will
complain as:

basic-save-buffer-2: .../baz/foo: no such directory

which is misleading since ".../baz/foo" is supposed to be a file.

Assume now I notice my mistake and want to `save-buffer' *scratch* in
the existing directory ".../bar/".  Emacs will insist on storing my
buffer as ".../baz/foo" and continue telling me that such a directory
doesn't exist.

After a while `auto-save-mode' may kick in and add to my confusion by
complaining

Auto-saving foo: Opening output file: no such file or directory, .../baz/#foo#

This confusion could be relieved by the attached patch.

[-- Attachment #2: files.patch --]
[-- Type: text/plain, Size: 1428 bytes --]

*** files.el	Fri Mar  9 07:48:34 2007
--- files.el	Sat Mar 10 10:38:28 2007
***************
*** 3599,3606 ****
  		  (setq buffer-new-name (buffer-name buf))
  		  (kill-buffer buf))
  		(rename-buffer buffer-new-name)))
! 	  ;; If buffer has no file name, ask user for one.
! 	  (or buffer-file-name
  	      (let ((filename
  		     (expand-file-name
  		      (read-file-name "File to save in: ") nil)))
--- 3599,3607 ----
  		  (setq buffer-new-name (buffer-name buf))
  		  (kill-buffer buf))
  		(rename-buffer buffer-new-name)))
! 	  ;; If buffer has no file name or the visited file is not writable, ask
! 	  ;; user for one.
! 	  (or (and buffer-file-name (file-writable-p buffer-file-name))
  	      (let ((filename
  		     (expand-file-name
  		      (read-file-name "File to save in: ") nil)))
***************
*** 3681,3687 ****
  	  (if (not (file-directory-p dir))
  	      (if (file-exists-p dir)
  		  (error "%s is not a directory" dir)
! 		(error "%s: no such directory" buffer-file-name))
  	    (if (not (file-exists-p buffer-file-name))
  		(error "Directory %s write-protected" dir)
  	      (if (yes-or-no-p
--- 3682,3688 ----
  	  (if (not (file-directory-p dir))
  	      (if (file-exists-p dir)
  		  (error "%s is not a directory" dir)
! 		(error "%s: no such directory" dir))
  	    (if (not (file-exists-p buffer-file-name))
  		(error "Directory %s write-protected" dir)
  	      (if (yes-or-no-p

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Re: save-buffer when directory doesn't exist

[Jason Spiro]

martin rudalics <rudalics <at> gmx.at> writes:
> 
> Assume I modify *scratch* and try to `save-buffer' it as ".../bar/foo".
> (I know `write-file' should be used for this purpose but `save-buffer'
> offers the service as well.)  Assume further, I mistype the name as
> ".../baz/foo" where the subdirectory "baz" does not exist.  Emacs will
> complain as:
> 
> basic-save-buffer-2: .../baz/foo: no such directory
> 
> which is misleading since ".../baz/foo" is supposed to be a file.
> 
> Assume now I notice my mistake and want to `save-buffer' *scratch* in
> the existing directory ".../bar/".  Emacs will insist on storing my
> buffer as ".../baz/foo" and continue telling me that such a directory
> doesn't exist.
> 
> After a while `auto-save-mode' may kick in and add to my confusion by
> complaining
> 
> Auto-saving foo: Opening output file: no such file or directory, .../baz/#foo#
> 
> This confusion could be relieved by the attached patch.

I am not an Emacs developer, and I have not tested the patch (I am on a Windows
machine without Cygwin or patch(1) right now).  But Martin's problem seems to be
valid, and his patch seems like it will fix it.  Would it be helpful if I tested
the patch on my Linux PC?  I could check that it works and see if it does
something about the auto-save errors too.

Regards,
Jason

Re: save-buffer when directory doesn't exist

[martin rudalics]

> I am not an Emacs developer, and I have not tested the patch (I am on a Windows
> machine without Cygwin or patch(1) right now).  But Martin's problem seems to be
> valid, and his patch seems like it will fix it.  Would it be helpful if I tested
> the patch on my Linux PC?  I could check that it works and see if it does
> something about the auto-save errors too.

I just checked in a slightly modified version.  Could you test it on your
GNU Linux machine?

Re: save-buffer when directory doesn't exist

[Jason Spiro]

> I just checked in a slightly modified version.  Could you test it on your
> GNU Linux machine?
>
I like the new error message much better.  But now that I think about
it, the error message could be improved even more.  Instead of
"/ho,e/j/Desktop/: no such directory", how about this?

Cannot save /ho,e/jspiro/Desktop/todo.txt because directory /ho,e does not exist

I did 4 things different in my suggested example:  I used the word
"because";  I added a verbose explanation of why it failed;  I left
out the trailing slash on the directory name since I think it looks
better that way;  and I only mentioned the nonexistent directory /ho,e
and not its subdirectories.

By the way, what can be done about the annoying "can't auto-save"
messages?  I wish emacs would just auto-save to /tmp by default.

Cheers,
Jason

Re: save-buffer when directory doesn't exist

[martin rudalics]

 > I like the new error message much better.  But now that I think about
 > it, the error message could be improved even more.  Instead of
 > "/ho,e/j/Desktop/: no such directory", how about this?
 >
 > Cannot save /ho,e/jspiro/Desktop/todo.txt because directory /ho,e does
 > not exist
 >
 > I did 4 things different in my suggested example:  I used the word
 > "because";  I added a verbose explanation of why it failed;  I left
 > out the trailing slash on the directory name since I think it looks
 > better that way;  and I only mentioned the nonexistent directory /ho,e
 > and not its subdirectories.

Then I would have to change the text in `basic-save-buffer-2' as well.
I don't want to think about the consequences of doing that now.  BTW,
`file-exists-p' won't tell me which subdirectory doesn't exist.

 > By the way, what can be done about the annoying "can't auto-save"
 > messages?  I wish emacs would just auto-save to /tmp by default.

Are you sure that you get them now?  When the directory doesn't exist
`set-visited-file-name' should _not_ be executed and auto-saving should
_not_ try to save the buffer.  Anything else wold be a bug.

Re: save-buffer when directory doesn't exist

[Jason Spiro]

2007/4/7, martin rudalics <rudalics@gmx.at> wrote:
>  > I like the new error message much better.  But now that I think about
>  > it, the error message could be improved even more.  Instead of
>  > "/ho,e/j/Desktop/: no such directory", how about this?
>  >
>  > Cannot save /ho,e/jspiro/Desktop/todo.txt because directory /ho,e does
>  > not exist
>  >
>  > I did 4 things different in my suggested example:  I used the word
>  > "because";  I added a verbose explanation of why it failed;  I left
>  > out the trailing slash on the directory name since I think it looks
>  > better that way;  and I only mentioned the nonexistent directory /ho,e
>  > and not its subdirectories.
>
> Then I would have to change the text in `basic-save-buffer-2' as well.
> I don't want to think about the consequences of doing that now.  BTW,
> `file-exists-p' won't tell me which subdirectory doesn't exist.

That's fair.  But wouldn't it be better to at least use a more verbose
text like "Cannot save file: no such directory /ho,e/j/Desktop"?

>  > By the way, what can be done about the annoying "can't auto-save"
>  > messages?  I wish emacs would just auto-save to /tmp by default.
>
> Are you sure that you get them now?  When the directory doesn't exist
> `set-visited-file-name' should _not_ be executed and auto-saving should
> _not_ try to save the buffer.  Anything else wold be a bug.

Never mind.

Regards,
Jason

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Re: save-buffer when directory doesn't exist

[martin rudalics]

 > That's fair.  But wouldn't it be better to at least use a more verbose
 > text like "Cannot save file: no such directory /ho,e/j/Desktop"?

Maybe.  But as I said earlier we would have to check all
file-saving related messages if we changed this one.