- `handle_update_xblock_upstream_link` is called asynchronously with celery. In `update_upstream_downstream_link_handler`, the xblock has the updated version, but when calling `handle_update_xblock_upstream_link` inside Celery, the xblock is outdated in a previous version, which is why the error occurs. This happens because `on_commit_changes_to` is executed before the MySQL transaction ends.
- Added `ImmediateOnCommitMixin` to be used in tests that need to call `on_commit_changes_to`. See https://github.com/openedx/edx-platform/pull/37485#issuecomment-3412979170 for more info
- Moving xmodule folder to root as we're dissolving sub-projects of common folder in edx-platform
- More info: https://openedx.atlassian.net/browse/BOM-2579
- -e common/lib/xmodule has been removed from the requirements as xmodule has itself become the part of edx-platform and not being installed through requirements
- The test files common/lib/xmodule/test_files/ have been removed as they are not being used anymore
