Re: PATCH: Unbreak `mailcap-mailcap-entry-passes-test'

[Katsumi Yamaoka <yamaoka@jpl.org>]

On Tue, 20 Oct 2015 11:10:55 +0200, Michael Sperber wrote:
> I had to apply to attached patch to make mailcap work on XEmacs.  I'm
> puzzled by this, as I think it should break mailcap for just about
> everyone.  On the other hand, I don't see how the code (without) the
> patch could work as advertised.

> So if somebody could review (and maybe apply) it, that - again - would
> be much appreciated.

This is what I grasped of how mailcap.el does:

What is passed to mailcap-mailcap-entry-passes-test is an entry
of a mailcap file (user's or system's) like this:

image/*; xv %s; test=test -n "$DISPLAY"

This entry is parsed by mailcap-parse-mailcap into:

((viewer . "xv %s") (type . "image/*") (test . "test -n \"$DISPLAY\""))

It is passed to mailcap-mailcap-entry-passes-test as an argument,
and the result is added to mailcap-mime-data.  Where the result is

((viewer . "xv %s") (type . "image/*") (test . t))

if $DISPLAY is not empty, otherwise:

((viewer . "xv %s") (type . "image/*") (test))

If your patch is applied, the `test' token will not be updated
whatever $DISPLAY is.

Regards,