Re: problems with emacsclient started by cygwin programs (mswindows)

[Stefan Monnier]

> I mostly agree.  The problem only happens when external pathnames get
> introduced into Emacs.  The ways this can happen are:
>  - command line
>  - server (used by emacsclient)
> I'm not sure they can get into Emacs in other meaningful ways.

They can show up in several other ways, e.g. in *compile*/*grep* if your
compiler/grep is using cygwin.

Enumerating them all and making them all do the right thing is rather
tedious/difficult, which is why cygwin-mount is fairly popular for those
people who mix cygwin and the native Windows port of Emacs: by handling
cygwin filenames everywhere, it's sure to handle them where needed.

>>> But there a mount from c:/cygwin to / so cygwin-mount should be able
>>> to translate /home/user/foo.el to c:/cygwin/home/user/foo.el.  At least
>>> in theory.
> But when it's OK to do this?  What if there was a c:/home/ and
> c:/cygwin/home, then what would /home refer to?  Could be c:/home/ and
> not c:/cygwin/home/.

Indeed, cygwin-mount isn't told when a file is using cygwin syntax and
when it uses some other syntax, so it has to guess.  That's probably why
it did not handle your /home (too ambiguous).

> To me, this global interpretation of pathnames (if I correctly
> interpret what you are suggesting for expand-file-name or
> cygwin-mount) to fix them is asking for trouble.  On the other hand, I
> know the Emacs command line and Emacs server inputs will for me always
> have cygwin paths on them.

OK.

> I do (now) agree that hook should be applied to the command line
> processing.  If we come to agreement on all this I can look into doing
> that, too.

That sounds great.  I think we should simply add a new function
file-name-import-function (feel free to come up with a better name)
which by default is set to `identity' and whose intention is to
translate an external file name (coming from another process) into one
usable inside Emacs.  And then call this function where appropriate.


        Stefan