bug#13272: 24.3.50; `diff' output header line shows MS Windows root incorrectly

bug#13272: 24.3.50; `diff' output header line shows MS Windows root incorrectly

[Drew Adams]

I'm seeing this now in the very first line of my `M-x diff' output:
 
diff -c c\:/foo/simple.el c\:/foo/simple-patched-2012-12-24.el
 
The "c\:/" part is incorrect.  It makes no sense to write that.  It
should be written "c:/" - the `:' should not have a backslash in front
of it
 
The lines that follow the first line are, however, correct:
 
*** c:/foo/simple.el Mon Dec 24 13:48:06 2012
--- c:/foo/simple-patched-2012-12-24.el Mon Dec 24 14:00:56 2012
 
In GNU Emacs 24.3.50.1 (i386-mingw-nt5.1.2600)
 of 2012-12-18 on MS-W7-DANI
Bzr revision: 111265 eliz@gnu.org-20121218190556-x9wmq083vwecgu0f
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.7) --no-opt --enable-checking --cflags
 -Ic:/emacs/libs/libXpm-3.5.10/include -Ic:/emacs/libs/libXpm-3.5.10/src
 -Ic:/emacs/libs/libpng-dev_1.4.3-1_win32/include
 -Ic:/emacs/libs/zlib-dev_1.2.5-2_win32/include
 -Ic:/emacs/libs/giflib-4.1.4-1-lib/include
 -Ic:/emacs/libs/jpeg-6b-4-lib/include
 -Ic:/emacs/libs/tiff-3.8.2-1-lib/include
 -Ic:/emacs/libs/libxml2-2.7.8-w32-bin/include/libxml2
 -Ic:/emacs/libs/gnutls-3.0.9-w32-bin/include
 -Ic:/emacs/libs/libiconv-1.9.2-1-lib/include'
 

bug#13272: 24.3.50; `diff' output header line shows MS Windows root incorrectly

[Eli Zaretskii]

> From: "Drew Adams" <drew.adams@oracle.com>
> Date: Mon, 24 Dec 2012 14:07:05 -0800
> 
> I'm seeing this now in the very first line of my `M-x diff' output:
>  
> diff -c c\:/foo/simple.el c\:/foo/simple-patched-2012-12-24.el

That's your diff.exe at work, I'm quite sure: it tries to quote the
colon, because it's a Cygwin Diff and lives in the Unix world.  Don't
you see the same if you redirect Diff output to a file?

The version of Diff I have does this instead:

  diff -c "c:/foo/simple.el" "c:/foo/simple-patched-2012-12-24.el"

which is much more reasonable.

bug#13272: 24.3.50; `diff' output header line shows MS Windows root incorrectly

[Eli Zaretskii]

> Date: Tue, 25 Dec 2012 05:44:53 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 13272@debbugs.gnu.org
> 
> > From: "Drew Adams" <drew.adams@oracle.com>
> > Date: Mon, 24 Dec 2012 14:07:05 -0800
> > 
> > I'm seeing this now in the very first line of my `M-x diff' output:
> >  
> > diff -c c\:/foo/simple.el c\:/foo/simple-patched-2012-12-24.el
> 
> That's your diff.exe at work, I'm quite sure: it tries to quote the
> colon, because it's a Cygwin Diff and lives in the Unix world.

There's another possibility: that this quoting is done by
shell-quote-argument.  What do you get if you evaluate the following
expression?

   (shell-quote-argument "c:/foo/simple.el")

If you get the colon quoted with a backslash, then my crystal ball
says that you customized shell-file-name to point to the Cygwin Bash,
in which case this is normal behavior, see shell-quote-argument.

bug#13272: 24.3.50; `diff' output header line shows MS Windows root incorrectly

[Drew Adams]

> > That's your diff.exe at work, I'm quite sure: it tries to quote the
> > colon, because it's a Cygwin Diff and lives in the Unix world.
> 
> There's another possibility: that this quoting is done by
> shell-quote-argument.  What do you get if you evaluate the following
> expression?
> 
>    (shell-quote-argument "c:/foo/simple.el")
> 
> If you get the colon quoted with a backslash, then my crystal ball
> says that you customized shell-file-name to point to the Cygwin Bash,
> in which case this is normal behavior, see shell-quote-argument.

I see this returned from M-: (which prints the result):

"c\\:/foo/simple.el"

Yes, I have customized it:

Its value is
"C:/cygwin/bin/bash.exe"
Original value was 
"c:/emacs/trunk/bin/cmdproxy.exe"

And yes, I see that also in Emacs 23 and 22.  (However, prior to Emacs 22 I see
this instead:

"\"c:/foo/simple.el\""

Guess I never noticed this before.  I closed the bug.  Thx.

bug#13272: 24.3.50; `diff' output header line shows MS Windows root incorrectly

[Eli Zaretskii]

> From: "Drew Adams" <drew.adams@oracle.com>
> Cc: <13272@debbugs.gnu.org>
> Date: Tue, 25 Dec 2012 21:46:38 -0800
> 
> And yes, I see that also in Emacs 23 and 22.  (However, prior to Emacs 22 I see
> this instead:
> 
> "\"c:/foo/simple.el\""

I guess prior to Emacs 22, shell-quote-argument on Windows didn't
support Posix shells.