bug#10827: 24.0.93; M-RET behaviour with M-x diff-buffer-with-file RET

[Jambunathan K <kjambunathan@gmail.com>]

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

>> 1. Make some modification to a file and don't save it.  
>> 2. Do M-x diff-buffer-with-file RET.
>> 3. Pick a modified line and press M-RET.
>> 4. Now the user is prompted for a file.
>
> When I try it, Emacs just jumps to the corresponding line in the
> original buffer without prompting the user for a file name.
> Could the problem be triggered by some particular customization
> of yours?  (I.e. try to reproduce it with "emacs -Q" and if the problem
> doesn't appear there, try to figure out which part of your config
> triggers the problem).

I am on Windows + Cygwin. The immediate problem seems to be that
`diff-hunk-file-names' assumes that file names have no spaces.

If I (blindly) modify the following regexp in `diff-hunk-file-names'

--8<---------------cut here---------------start------------->8---
"[-*][-*][-*] \\(\\S-+\\)\\(\\s-.*\\)?\n[-+][-+][-+] \\(\\S-+\\)"
--8<---------------cut here---------------end--------------->8---

to 

--8<---------------cut here---------------start------------->8---
"[-*][-*][-*] \\(.+\\)\\(\\s-.*\\)?\n[-+][-+][-+] \\(.+\\)"
              ^^^^^^^^                            ^^^^^^^^^ 
--8<---------------cut here---------------end--------------->8---

I get the right behaviour.

Down below is a *Diff* buffer that I get with `diff-buffer-with-file'.

With re-builder, you can see that the first regexp fails to "collect"
the files correctly.  The regexp (incorrectly) matches only part of the
filename/buffer name and not the whole name.

I also have my doubts regarding the correctness of another regexp
towards the end of `diff-hunk-file-names' which looks like this.

--8<---------------cut here---------------start------------->8---
"^diff \\(-\\S-+ +\\)*\\(\\S-+\\)\\( +\\(\\S-+\\)\\)?"
--8<---------------cut here---------------end--------------->8---

In summary, review the regexps in lisp/vc/diff-mode.el so that they do
the right thing on Windows where filenames can have spaces.

--8<---------------cut here---------------start------------->8---
diff -pub -L c\:/Documents\ and\ Settings/kjambunathan/My\ Documents/My\ Data/devel/devel-notes.org -L \#\<buffer\ devel-notes.org\> c\:/Documents\ and\ Settings/kjambunathan/My\ Documents/My\ Data/devel/devel-notes.org c\:/Documents\ and\ Settings/kjambunathan/My\ Documents/My\ Data/tmp/buffer-content-3804sEa
--- c:/Documents and Settings/kjambunathan/My Documents/My Data/devel/devel-notes.org
+++ #<buffer devel-notes.org>
@@ -4,6 +4,7 @@
 
 
 
+
 http://cygwin.com/ml/cygwin/2006-05/msg00756.html
 
 # texi to pdf conversion using miktex

Diff finished.  Thu Mar 22 20:04:55 2012

--8<---------------cut here---------------end--------------->8---