flatpak-builder: No GSettings schemas are installed on the system

[Alec Leamas]

Dear list,

We are all of a sudden getting flatpak-builder errors like

(appstream-compose:2): GLib-GIO-ERROR **: 02:22:58.138: No GSetting 
schemas are installed on the system

when running the appstream-compose step. Complete log in  [1]. This is 
on an otherwise unmodified build which has worked.

Digging into this it seems it is about the file gschemas.compiled which 
is expected in one on the XDG_DATA_DIRS paths. This exists as expected 
in the builder VM as /usr/share/glib-2.0/schemas/gschemas.compiled

However, when inspecting the failed build sandbox the file 
gschemas.compiled is missing in /usr/share/glib2.0/schemas and 
elsewhere. I assume this is the very core of this problem (?)

A possible work around would be to use glib-compile-schemas(1) to create 
the missing gschemas.compiled. However, appstream-compose seems to look 
in XDG_DATA_DIRS paths. XDG_DATA_DIRS is set by flatpak-builder to a set 
read-only file system paths. So no joy.

Can anyone out there shed some light on this?

Cheers!
--alec


[1]: 
https://app.circleci.com/pipelines/github/leamas/OpenCPN/4873/workflows/b210a1dd-8748-42ac-8d83-c93c7900018b/jobs/10156