Why would I see g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed?

[Brendan Long <self brendanlong com>]

I'm not sure if this is a Glib, Meson or Vala thing, but I don't even understand why this glib error would ever happen so I hope this is the right place to ask (I know it means "this type is null", but I have no idea why that would ever be the case).

I'm trying to convert a Vala project that uses dynamically loaded plugins to Meson:

https://github.com/jangernert/FeedReader/pull/662

For some reason, linking a test exectable with one of our plugins causes errors like:

$ ./plugins/backend/feedbin/test_feedbin

/feedbinapi/construct: 

(./plugins/backend/feedbin/test_feedbin:27002): GLib-GObject-CRITICAL **: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

Trace/breakpoint trap (core dumped)

< div>

The file is just a simple class that extends GLib.object: https://github.com/brendanlong/FeedReader/blob/meson/plugins/backend/feedbin/feedbinAPI.vala

The meson build is here, if that matters: https://github.com/brendanlong/FeedReader/blob/meson/plugins/backend/feedbin/meson.build

We were getting similar issues when linking our main library statically, but it's a shared library now (and the plugin has always been a shared library).

The only things I could find on Google were versioning issues, but I get this error in Docker, where no other version of FeedReader is installed:

https://circleci.com/g h/brendanlong/FeedReader/206

Can someone help me understand what's going wrong, and what I might do to fix it?