feat!: remove version from library serializer

The ContentLibraryMetadata used to hold a version field that was meant
to represent the version of the library as a whole. This is a holdover
from v1 libraries, where all changes to the library resulted in a new
version of the content, and that version indicator was used by courses
to know whether or not an update was available.

This maps poorly to Learning Core backed libraries for a number of
reasons:

1. LC-backed libraries have Draft and Published branches, meaning that
   a global "version" may be ambiguous.
2. LC-backed libraries have things like tagging and collections, where
   modifications are explicitly *not* versioned at all, and do not show
   up in either the publish log or the draft change log.
3. Courses that borrow content from LC-backed libraries track
   versioning at the level of the individual thing being borrowed, e.g.
   a single Component. This is in keeping with the goal to have very
   large libraries with many small bits of content to search and use.

This commit removes the notion of a Library-global version entirely for
v2 (LC-backed) libraries. This does not affect legacy v1 libraries that
are backed by ModuleStore.

openedx/core/djangoapps/content_libraries/api/libraries.py

@@ -289,7 +289,6 @@ def get_metadata(queryset: QuerySet[ContentLibrary], text_search: str | None = N
             key=lib.library_key,
             title=lib.learning_package.title if lib.learning_package else "",
             description="",
-            version=0,
             allow_public_learning=lib.allow_public_learning,
             allow_public_read=lib.allow_public_read,
 
@@ -352,22 +351,6 @@ def get_library(library_key: LibraryLocatorV2) -> ContentLibraryMetadata:
     has_unpublished_deletes = authoring_api.get_entities_with_unpublished_deletes(learning_package.id) \
                                            .exists()
 
-    # Learning Core doesn't really have a notion of a global version number,but
-    # we can sort of approximate it by using the primary key of the last publish
-    # log entry, in the sense that it will be a monotonically increasing
-    # integer, though there will be large gaps. We use 0 to denote that nothing
-    # has been done, since that will never be a valid value for a PublishLog pk.
-    #
-    # That being said, we should figure out if we really even want to keep a top
-    # level version indicator for the Library as a whole. In the v1 libs
-    # implemention, this served as a way to know whether or not there was an
-    # updated version of content that a course could pull in. But more recently,
-    # we've decided to do those version references at the level of the
-    # individual blocks being used, since a Learning Core backed library is
-    # intended to be referenced in multiple course locations and not 1:1 like v1
-    # libraries. The top level version stays for now because LegacyLibraryContentBlock
-    # uses it, but that should hopefully change before the Redwood release.
-    version = 0 if last_publish_log is None else last_publish_log.pk
     published_by = ""
     if last_publish_log and last_publish_log.published_by:
         published_by = last_publish_log.published_by.username
@@ -377,7 +360,6 @@ def get_library(library_key: LibraryLocatorV2) -> ContentLibraryMetadata:
         title=learning_package.title,
         description=learning_package.description,
         num_blocks=num_blocks,
-        version=version,
         last_published=None if last_publish_log is None else last_publish_log.published_at,
         published_by=published_by,
         last_draft_created=last_draft_created,
@@ -454,7 +436,6 @@ def create_library(
         title=title,
         description=description,
         num_blocks=0,
-        version=0,
         last_published=None,
         allow_public_learning=ref.allow_public_learning,
         allow_public_read=ref.allow_public_read,

openedx/core/djangoapps/content_libraries/rest_api/serializers.py

@@ -38,7 +38,6 @@ class ContentLibraryMetadataSerializer(serializers.Serializer):
     title = serializers.CharField()
     description = serializers.CharField(allow_blank=True)
     num_blocks = serializers.IntegerField(read_only=True)
-    version = serializers.IntegerField(read_only=True)
     last_published = serializers.DateTimeField(format=DATETIME_FORMAT, read_only=True)
     published_by = serializers.CharField(read_only=True)
     last_draft_created = serializers.DateTimeField(format=DATETIME_FORMAT, read_only=True)

openedx/core/djangoapps/content_libraries/tests/test_content_libraries.py

@@ -69,7 +69,6 @@ class ContentLibrariesTestCase(ContentLibrariesRestApiTest):
             "slug": "téstlꜟط",
             "title": "A Tést Lꜟطrary",
             "description": "Just Téstꜟng",
-            "version": 0,
             "license": CC_4_BY,
             "has_unpublished_changes": False,
             "has_unpublished_deletes": False,