bookmarks / switch-to-buffer

bookmarks / switch-to-buffer

[David Reitter]

The function `bookmark-jump' failed to work in my environment, where  
switch-to-buffer is advised.

The reason was that bookmark-jump expects switch-to-buffer to return  
a non-nil value (if succeeded), but switch-to-buffer is not actually  
documented to do so.

Therefore I'd suggest to ignore the return value of switch-to-buffer  
in bookmark's bookmark-jump function. This fixed the problem for me.

*** bookmark.el 19 Oct 2005 09:45:43 -0000      1.84
--- bookmark.el 10 Nov 2005 00:46:21 -0000
***************
*** 1062,1068 ****
     (bookmark-maybe-historicize-string bookmark)
     (let ((cell (bookmark-jump-noselect bookmark)))
       (and cell
!          (switch-to-buffer (car cell))
            (goto-char (cdr cell))
          (progn (run-hooks 'bookmark-after-jump-hook) t)
          (if bookmark-automatically-show-annotations
--- 1062,1068 ----
     (bookmark-maybe-historicize-string bookmark)
     (let ((cell (bookmark-jump-noselect bookmark)))
       (and cell
!          (or (switch-to-buffer (car cell)) t)
            (goto-char (cdr cell))
          (progn (run-hooks 'bookmark-after-jump-hook) t)

Re: bookmarks / switch-to-buffer

[Luc Teirlinck]

David Reitter wrote:

   The reason was that bookmark-jump expects switch-to-buffer to return  
   a non-nil value (if succeeded), but switch-to-buffer is not actually  
   documented to do so.

>From the docstring:

This function returns the buffer it switched to.

>From the description of the function in the Elisp manual:

It returns the buffer that it switched to.

   Therefore I'd suggest to ignore the return value of switch-to-buffer  
   in bookmark's bookmark-jump function. This fixed the problem for me.

I believe that you should fix your problem locally by fixing your advise.

If you advise a function to return a value that is different from the
documented one, then of course you run the risk to run into problems.
That is a bug in your advise, not a bug in Emacs.

Sincerely,

Luc.

Re: bookmarks / switch-to-buffer

[Karl Fogel]

Luc Teirlinck <teirllm@dms.auburn.edu> writes:
> If you advise a function to return a value that is different from the
> documented one, then of course you run the risk to run into problems.
> That is a bug in your advise, not a bug in Emacs.

I agree with Luc on this one.

The code may be a bit misleading there, because the return value of
the 'switch-to-buffer' call isn't really used for its conditional
value in the 'and', it's just one of the things that needs to happen
in the sequence of events.  But it's still correct.  If you advise a
function in such a way as to change its documented return value, you
should be prepared for code to stop working...

Best,
-Karl