Re: shell-command causes problems with absolute/relative paths in TAGS

[Eli Zaretskii]

> From: "David Chappaz" <david.chappaz@free.fr>
> Date: Fri, 6 Jan 2012 13:04:57 -0000
> 
> Eli Zaretskii wrote
> > > If, before doing M-x shell, I evaluate
> > > (setq explicit-cmdproxy.exe-args  '("/q"))
> > > to prevent shell commands from being echoed, then suddenly the TAGS file
> > > is generated properly, with relative filenames.
> > 
> > I see no such variable in Emacs. 
> 
> The variable name depends on which shell you use. By default, only
> explicit-bash-args and explicit-sh-args are defined in emacs.
> On windows, cmdproxy.exe is the default shell, hence the variable name.

Well, I tried that on Windows with cmdproxy as the shell, and I still
don't see this variable.

> 2/ Now from e.g. a scratch buffer, I evaluate
> 
> (progn
>    (cd "C:/test/")
>    (call-process-region (point) (point) "C:/Program
> Files/Emacs/emacs-23.3/bin/cmdproxy.exe" nil (current-buffer) nil "-c"
> "ctags -e -L filelist.txt"))
> 
> which is more or less what M-x shell-command would do... then the result is
> incorrect.

Yes, I see the problem.

> 3/ Worse, if you kill the original shell buffer created in 1/, and repeat
> the same operation as in 1/... then the result is incorrect.
> 
> So it really looks like something is happening in call-process-region...

It must be a bug in ctags, no matter what call-process-region does.  I
suspect that it doesn't correctly handle the backslash in file names,
and fails to realize that C:\foo\bar\baz.c and C:/foo/bar share the
same directory.  That's because the "absolute" file names it produces
are of the form "C:\foo\bar\./file", note the mixture of forward- and
back-slashes.