Dear Maintainer,

I checked, and it seems I had packages form tetsinginstalled - the stable
1.42.4-8~deb10u1 version has the required types.

I find nothing in the NEWS or debian changelog about this, so this is
likely an oversight by upstream, it's not the first time that they broke
subclassing.

I'm sorry, I replied too quickly on the bugreport without realising that it
doesn't yet have an id assigned, so #974140 and #974139 belong together, but
I don't know how to merge them.

Control: merge 974139 974140
Control: retitle 974139 libpango1.0-dev: PangoFcFont, PangoFcFontMap no longer subclassable
Control: forwarded 974139 https://gitlab.gnome.org/GNOME/pango/-/issues/513
Control: tags 974139 = upstream wontfix

Sorry, I don't think it's appropriate for Debian to be unilaterally
changing Pango's API. If upstream makes these APIs public again, we can
pick that up; but if upstream confirms that they're intentionally private,
making them public again in Debian is just going to cause us more trouble
in future.

    smcv

I think this can't be a wontfix, as it directly breaks debian policy
(8.1), as the ABI has changed incompatibly.

upstream has confirmed that pango is essentially unmaintained and they do
not keep ABI compatibility, or more exactly, they change the ABI without
bumping the soname.

Since these ABI changes can easily cause security issues as it creates
out-of-bound writes, I think debian at the very least has to bump the
soname version to avoid this.