The `Library.tag` data is supposed to be runtime only, so needs to be
cleared when reading data from blendfile.
This fixes the 'need resync' status of a library staying around forever
once set, annoying visual warning in the Outliner.
The `lib_link` callback cannot always be fully replaced/removed, as in
some case it is also doing some validation checks, or data editing based
on the result of lib_linking internal ID pointers.
The callback has been renamed for that purpose, from `read_lib` to
`read_after_liblink`. It is now called after all ID pointers have been
fully lib-linked for the current ID, but still before the call to
`do_versions_after_linking`.
This change should not have any behavioral effect. Although in theory
the side-effect of this commit (to split lib linking itself, and the
validation/further processing code) into two completely separated steps
could have some effects, in practice none are expected, and tests did
not show any changes in behavior either..
Part of implementing #105134: Removal of readfile's lib_link & expand code.
The `expand` callback is 'trivial' to replace, since it is only iterating
over ID pointers and calling a callback.
The only change in behavior here is that some pointers that were not
processed previously will now be.
In practice this is not expected to have any real effect (usually
the IDs used by these pointers would have been expanded through other
usages anyway). But it may solve a few corner cases, undocumented issues
though.
Part of implementing #105134: Removal of readfile's lib_link & expand code.
This commit adds a new option flag to the lib_query foreach_id code,
which will make deprecated ID pointers to be processed as well.
NOTE: Currently there is no report to the callbakcs about the fact that
it is processing a deprecated ID. This can be easily added later if it
becomes necessary.
Part of implementing #105134: Removal of readfile's lib_link & expand code.
Also see #103343.
Couldn't move two files yet:
* `softbody.c`: The corresponding regression test fails. It seems like the
conversion to C++ changes floating point accuracy, but it's not clear where that happens exactly.
* `writeffmpeg.c`: Is a bit more complex to convert because of the static array in `av_err2str`.
Pull Request: https://projects.blender.org/blender/blender/pulls/110182
