After we merged this PR: https://github.com/openedx/edx-platform/pull/33920
this error began popping up in logs:
Unable to load XBlock 'staffgradedxblock'
....
ImportError: cannot import name 'get_course_blocks' from
partially initialized module 'lms.djangoapps.course_blocks.api'
(most likely due to a circular import) ...
The root cause was the new imports of `derived_key` and `BlockKey` into
xmodule/library_content_block.py. Those new imports come from
xmodule/modulestore/store_utilities.py, which runs
`XBlock.load_classes()` at the module level, which fails because we are
still in the process of loading xmodule/library_content_block.
As a solution, we move both `derived_key` and `BlockKey` to
xmodule/util/keys.py. We could potentially move that file to opaque-keys
eventually, depending on how well we think that those concepts generalize.
Also:
* We rename the function from derived_key to derive_key, as
functions should be verbs.
* We combine the first to parameters of derive_key (a source ContextKey
and a source BlockKey) into a single parameter (a source UsageKey). In
my opinion, this makes the function call easier to understand.
e8b60aef60