MIME database

[Ludovic Courtès]

Hello,

(Moving the discussions to guix-devel.)

address@hidden skribis:

> I was wondering why my pdf documents were getting opened in Gimp by default 
> instead of Evince, so I investigated xdg-open and found it uses mimeopen as a 
> fallback, and packaged it. Turns out it didn't make a difference and the 
> issue was simply that the generated mimedata.cache in xdg-mime-database had 
> Gimp listed before Evince.

Oh, good catch.  Profile generation is sensitive to package order; so
indeed, if GIMP comes first, it “wins.”

> I was also I little confused that xdg-mime-database produces so many 
> conflicts with shared-mime-info. It's role appears to be to update the data 
> in shared-mime-data and have it overshadow the original data when  conflicts 
> are resolved during profile generation. Looks ugly seeing all those conflicts 
> though.

I guess it’s OK in that users normally don’t want to install these
packages at all, let alone installing both in the same profile.

> I had a look at Fedora's version. They just have a single shared-mime-data 
> package that runs update-mime-database, but also they add a few changes to 
> make Evince open pdf's instead of Gimp, among other changes.
>
> This makes me feel that it's desirable for us to also tweak mimedata to make 
> it more sensible -- Pdf's should open in a pdf reader before it opens in an 
> image editor. It seems unrealistic to only tweak upstream projects to make 
> all this mimedata mesh together perfectly to produce ideal default behaviour.

Right, so I think the immediate course of action here would be to patch
GIMP’s MIME data so that it does not register as a PDF viewer.

If we stumble upon other issues like that, we can fix them similarly.

How does that sound?

Thanks for investigating!

Ludo’.