mime apps specification

[Ryan Lortie]

hi David,

On Wed, Apr 2, 2014, at 11:06, David Faure wrote:
> After so many years, he's finally a proposal for a unified mechanism for 
> selecting the default application for a given mimetype.

A couple notes after my attempts to integrate this work with the desktop
file index:

The multiple defaults thing is a bit strange and it makes the cache more
complex.  It would be nice to just give the desktop file ID for each
type.

What is the interaction between the mime cache and replaced desktop
files?

Specifically, imagine this situation: we have 'x.desktop' in ~ and /usr.
 In /usr it supports MimeType=text/plain, but the .desktop file in ~ has
no such mention.  In /usr it is listed in mimeapps.info as the default
for text/plain.

As written, the spec suggests that because x.desktop is mentioned as the
default for text/plain we should implicitly add it.  What if it was in
Added, though?  It seems that, at any given level, having an Added
association for a desktop file that already lists the mime type among
its MimeTypes= should be redundant, but here we see that we would get a
different result.

Is this desirable?  What does it mean if the user replaces a desktop
file with one in their homedir that has a more restrictive set of
supported mimetypes?  Probably that means that the version that they
install does not support the wider range, and then the added association
is probably inappropriate -- doubly so if it was only there in order to
break a tie over the choice of default.

Thoughts?

Cheers