Re: [O] Version 7.5: C-c C-t <anything> fails with "args out of range"

[David Maus]

At Tue, 8 Mar 2011 15:08:57 -0800,
Josh Berry wrote:
>
> Hi list,
>
> I just upgraded from org-mode 7.4 to 7.5, and I can't set or change
> TODO states at all with C-c C-t now; an args-out-of-range error gets
> raised.  I've tried doing a "make clean" in my org-mode checkout, to
> no avail.
>
> I'm running GNU emacs 23.2.1 on Mac OSX (in Aqua), installed via
> Homebrew.  Debugger backtrace is pasted below.
>
> [[BTW, please forgive me if this isn't a well-formed bug report; I'm
> relatively new to Emacs and don't know Elisp.  Just let me know if you
> need anything else.]]

Just a fast comment: Couldn't this be a problem with the macro
`org-with-wide-buffer'?

#+begin_src emacs-lisp
(defmacro org-with-wide-buffer (&rest body)
  "Execute body while temporarily widening the buffer."
  `(let ((beg (point-min)) (end (point-max)) (pos (point)))
     (prog2
         (widen)
         ,@body
       (narrow-to-region beg end)
       (goto-char pos))))
#+end_src

What if BODY inserts or deletes characters inside the narrowed region?
In this case the upper boundary of the region is no longer (point-max)
before executing body. Thus the buffer might be narrowed to the wrong
region after executing body. No, wait: If BODY inserts or deletes
something inside OR above the region the boundaries of the originally
narrowed region change, don't they?

This would explain the error: Buffer is narrowed to a region that
happens to end at eob.  BODY deletes something inside the region, eob
is decreased by the number of characters deleted. The call to
`narrow-to-region' tries to narrow to a region with an upper boundary
greater than eob -- and that's not possible.

Solution? Not sure. The function must take into account that BODY
modifies buffer in a way that changes buffer in a way that requires
adjustment of the region boundaries OR even in a way that removes the
part of buffer that contained the region.

So something like this would fix it: Store markers of beginning and
end of region. IIRC they will move with inserts and deletes. After
executing body narrow to position of these markers if they exist. If
marker for point-max is gone, use eob. If both are gone... Don't
narrow at all?

Best,

 -- David
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