appcenter fails to compile on fedora 34+ (probably caused by appstream 0.13)

[decathorpe]

appcenter from the master branch fails to compile on fedora 34 since about a month ago. I am unsure whether this issue was caused by a Vala or libappstream update, but it looks like one of the types is no longer compatible (weak vs. non-weak AppStream.Components in the array). However, I think that appstream 0.13.1 might be the cause. The last good build of appcenter was still with appstream 0.12.11.

../src/Core/FlatpakBackend.vala:289.53-289.57: error: Assignment: Cannot convert from `GLib.GenericArray<AppStream.Component>' to `GLib.GenericArray<weak AppStream.Component>?'
        GLib.GenericArray<weak AppStream.Component> comps = user_appstream_pool.search (query);
                                                    ^^^^^
../src/Core/PackageKitBackend.vala:396.53-396.57: error: Assignment: Cannot convert from `GLib.GenericArray<AppStream.Component>' to `GLib.GenericArray<weak AppStream.Component>?'
        GLib.GenericArray<weak AppStream.Component> comps = appstream_pool.search (query);
                                                    ^^^^^
../src/Views/AbstractView.vala:34.55-34.93: warning: Access to possible `null'. Perform a check or use an unsafe cast.
                    if (child is Views.AppInfoView && (child as Views.AppInfoView).to_recycle) {
                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Compilation failed: 2 error(s), 1 warning(s)

Relevant package versions:

• appstream 0.13.1
• vala 0.48.13
• meson 0.56.0
• gcc 11 pre-release

[decathorpe]

Fixed by PR #1493 , thanks!