Created attachment 129146 [details] [review]
possible default applications are separated by semicolons
on my Fedora 24 system, xdg-mime will return a semicolon separated list (from /usr/share//applications/mimeapps.list). xdg-open will use the whole string verbatim as the name of the desktop file, and it fails.
$ /bin/xdg-mime query default image/jpeg
$ /bin/xdg-mime query default image/svg+xml
notice the trailing semicolon.
it seems to me xdg-open should split on ";" and look for each application in turn. I have a patch to do so at
the patch is enclosed. it also fixes a trivial but critical typo in xdg-open.
Alternatively, I think we can consider that 'xdg-mime default' return at most a single (validated) value. By validated, I mean that it must/should(?) be verified to exist.