GNU bug report logs - #21262
25.0.50; Diff-mode gets confused about its narrowing if hunk source not found

Previous Next

Full log

Message #19 received at 21262-done <at> debbugs.gnu.org (full text, mbox):

From: charles <at> aurox.ch (Charles A. Roelli)
To: npostavs <at> users.sourceforge.net
Cc: 21262-done <at> debbugs.gnu.org, dima <at> secretsauce.net
Subject: Re: bug#21262: 25.0.50;
 Diff-mode gets confused about its narrowing if hunk source not found
Date: Sun, 27 Aug 2017 14:21:05 +0200

> Date: Tue, 22 Aug 2017 16:02:17 +0200
> From: charles <at> aurox.ch (Charles A. Roelli) 
> 
> > From: npostavs <at> users.sourceforge.net
> > Cc: Dima Kogan <dima <at> secretsauce.net>,  21262 <at> debbugs.gnu.org
> > Date: Mon, 21 Aug 2017 20:18:39 -0400
> >
> > Looks like a reasonable fix to me (though I know only a little bit of
> > diff-mode).  Here it is again ignoring whitespace, which I think makes
> > it easier to see what is happening:
> > 
> > modified   lisp/vc/diff-mode.el
> > @@ -874,6 +874,8 @@ diff-find-file-name
> >      ;; Flush diff-remembered-files-alist if the default-directory is changed.
> >      (set (make-local-variable 'diff-remembered-defdir) default-directory)
> >      (set (make-local-variable 'diff-remembered-files-alist) nil))
> > +  (save-restriction
> > +    (widen)
> >      (save-excursion
> >        (unless (looking-at diff-file-header-re)
> >          (or (ignore-errors (diff-beginning-of-file))
> > @@ -919,7 +921,7 @@ diff-find-file-name
> >  				   (file-name-nondirectory file)))
> >               (set (make-local-variable 'diff-remembered-files-alist)
> >                    (cons (cons fs file) diff-remembered-files-alist))
> > -           file))))))
> > +             file)))))))
> > 
> > Perhaps we should swap the save-restriction and save-excursion around
> > though?  The elisp manual says:
> > 
> >      If you use both `save-restriction' and `save-excursion' together,
> >      `save-excursion' should come first (on the outside).  Otherwise,
> >      the old point value would be restored with temporary narrowing
> >      still in effect.
> 
> Good point, thank you.  I'll apply the attached patch in a few days if
> there's no further discussion.

I've pushed the fix, closing the bug now.

  commit 208a3cb05f4d954abc9dd6c8cd858ef2bedd7cb4
  Date:   Tue Aug 22 15:57:01 2017 +0200

  Fix 'diff-goto-source' when buffer is narrowed (Bug#21262)

  * lisp/vc/diff-mode.el (diff-find-file-name): Save the current
  narrowing, and widen the buffer before searching for the name of the
  file corresponding to the diff.

  With thanks to Noam Postavsky.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.