Split out XDG_CURRENT_DESKTOP handling to a separate function and make
sure that it drops all the invalid entries properly. Earlier a bad
entry could slip through the checks by sitting just after another bad
entry, like in env being set to `invalid1!:invalid2!`, where
`invalid2!` could slip the checks.
None of these files starts with a #! line, and they are not native
binary executables, so if a user attempts to execute them as a program,
Unix shells will run them as /bin/sh scripts. This is not going to end
well, since none of them are shell scripts (the gio bash completion
is for bash, which is not a lowest-common-denominator POSIX shell, and
in any case is designed to be sourced rather than executed).
Fixes: #1539
Signed-off-by: Simon McVittie <smcv@collabora.com>
g_desktop_app_info_load_from_keyfile() refuses to load .desktop files
where the executable doesn't exist. Therefore whether or not the .desktop
file added in commit 148995544 is actually considered during tests depends
on /usr/bin/flatpak being installed. This isn't a safe assumption to make,
so use /bin/sh to test filtering of "prefix" commands.
https://bugzilla.gnome.org/show_bug.cgi?id=795488
Add the basename from the first component of the Exec line to the list of
strings to search for via g_desktop_app_info_search().
We treat Exec as a fairly strong match -- just below the visible name.
Add a testcase to make sure everything is working OK.
https://bugzilla.gnome.org/show_bug.cgi?id=725023
