Reports from the internal operator weren't forwarded to the Python
operator, they were printed in the console instead.
Resolve by moving the operator to C++, use a utility function
to launch the external editor instead of an operator.
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.
Listing the "Blender Foundation" as copyright holder implied the Blender
Foundation holds copyright to files which may include work from many
developers.
While keeping copyright on headers makes sense for isolated libraries,
Blender's own code may be refactored or moved between files in a way
that makes the per file copyright holders less meaningful.
Copyright references to the "Blender Foundation" have been replaced with
"Blender Authors", with the exception of `./extern/` since these this
contains libraries which are more isolated, any changed to license
headers there can be handled on a case-by-case basis.
Some directories in `./intern/` have also been excluded:
- `./intern/cycles/` it's own `AUTHORS` file is planned.
- `./intern/opensubdiv/`.
An "AUTHORS" file has been added, using the chromium projects authors
file as a template.
Design task: #110784
Ref !110783.
