feat: History log logic for Components and Containers (openedx#38178)

**Publish history groups: Pre-Verawood vs Post-Verawood**

The `openedx-content` library added a `direct` field to `PublishLogRecord` starting in the Verawood release (openedx/openedx-core#539). This field changes how publish history groups are structured, so the endpoint handles both eras:

**Pre-Verawood** (`PublishLogRecord.direct is None`): When a container and its components are published together, each entity produces its own independent group, even though they share the same `publish_log_uuid`. For example, publishing a Unit with 3 components creates 4 separate groups. Each group has `scope_entity_key` set to that specific entity's key, which the frontend must pass to the entries endpoint to fetch that entity's individual changes.

**Post-Verawood** (`PublishLogRecord.direct is not None`): The `direct` field marks which entities the user explicitly clicked "Publish" on (`direct=True`) vs. which were pulled in as side effects (`direct=False`, e.g. a shared component published from a sibling container). In this era, all entities from the same `PublishLog` are merged into a single group, and `direct_published_entities` lists only the explicitly published items. The `scope_entity_key` is `null` — the frontend uses the current container key to fetch entries.

This design means the frontend does not need era awareness: it always uses `group.scope_entity_key ?? currentContainerKey` when calling the entries endpoint.

**Functions**

- Implements python api and REST_API functions to get the history log for a component:
    - `get_library_component_draft_history`: Return the draft change history for a library component since its last publication.
    - `get_library_component_publish_history`: Return the publish history of a library component as a list of groups.
    - `get_library_component_publish_history_entries`: Return the individual draft change entries for a specific publish event.
    - `get_library_component_creation_entry`: Return the creation entry (who created it and when).
- Implements python api and REST_API functions to get the history log for containers:
    - `get_library_container_draft_history`: Return the combined draft history for a container and all of its descendant components.
    - `get_library_container_publish_history`: Return the publish history of a container as a list of groups.
    - `get_library_container_publish_history_entries`: Return the individual draft change entries for the container entity in a specific publish event.
    - `get_library_container_creation_entry`: Return the creation entry for a container.

Note: This used Claude's help to write the separation of the Post and Pre-Verawood eras

Author: ChrisChV

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

@@ -4,18 +4,39 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
+from datetime import datetime
+from typing import TypedDict
+from uuid import UUID
 
+from django.contrib.auth.models import AbstractUser
 from django.utils.translation import gettext as _  # noqa: F401
-from opaque_keys.edx.locator import LibraryUsageLocatorV2
+from opaque_keys.edx.locator import LibraryContainerLocator, LibraryLocatorV2, LibraryUsageLocatorV2
+from openedx_content.models_api import PublishableEntityVersion, PublishLogRecord
 
-from .libraries import PublishableItem, library_component_usage_key
+from openedx.core.djangoapps.user_api.accounts.image_helpers import get_profile_image_urls_for_user
+
+from .libraries import (
+    PublishableItem,
+    library_component_usage_key,
+)
 
 # The public API is only the following symbols:
 __all__ = [
     "LibraryXBlockMetadata",
     "LibraryXBlockStaticFile",
+    "LibraryHistoryEntry",
+    "LibraryHistoryContributor",
+    "LibraryPublishHistoryGroup",
 ]
 
+class ProfileImageUrls(TypedDict):
+    """URLs for a user's profile image in different sizes."""
+
+    full: str
+    large: str
+    medium: str
+    small: str
+
 
 @dataclass(frozen=True, kw_only=True)
 class LibraryXBlockMetadata(PublishableItem):
@@ -48,6 +69,7 @@ def from_component(cls, library_key, component, associated_collections=None):
             usage_key=usage_key,
             display_name=draft.title,
             created=component.created,
+            created_by=component.created_by.username if component.created_by else None,
             modified=draft.created,
             draft_version_num=draft.version_num,
             published_version_num=published.version_num if published else None,
@@ -63,6 +85,76 @@ def from_component(cls, library_key, component, associated_collections=None):
         )
 
 
+@dataclass(frozen=True)
+class LibraryHistoryEntry:
+    """
+    One entry in the history of a library component.
+    """
+    contributor: LibraryHistoryContributor | None
+    changed_at: datetime
+    title: str  # title at time of change
+    item_type: str
+    action: str  # "created" | "edited" | "renamed" | "deleted"
+
+
+@dataclass(frozen=True)
+class LibraryHistoryContributor:
+    """
+    A contributor in a publish history group, with profile image URLs.
+    """
+    username: str
+    profile_image_urls: ProfileImageUrls
+
+    @classmethod
+    def from_user(cls, user, request=None) -> LibraryHistoryContributor:
+        return cls(
+            username=user.username,
+            profile_image_urls=get_profile_image_urls_for_user(user, request),
+        )
+
+
+@dataclass(frozen=True)
+class DirectPublishedEntity:
+    """
+    Represents one entity the user directly requested to publish (direct=True).
+    Each entry carries its own title and entity_type so the frontend can display
+    the correct label for each directly published item.
+
+    Pre-Verawood groups have exactly one entry (approximated from available data).
+    Post-Verawood groups have one entry per direct=True record in the PublishLog.
+    """
+    entity_key: LibraryUsageLocatorV2 | LibraryContainerLocator
+    title: str               # title of the entity at time of publish
+    entity_type: str  # e.g. "html", "problem" for components; "unit", "section" for containers
+
+
+@dataclass(frozen=True)
+class LibraryPublishHistoryGroup:
+    """
+    Summary of a publish event for a library item.
+
+    Each instance represents one or more PublishLogRecords, and includes the
+    set of contributors who authored draft changes between the previous publish
+    and this one.
+
+    Pre-Verawood (direct=None): one group per entity × publish event.
+    Post-Verawood (direct!=None): one group per unique PublishLog.
+    """
+    publish_log_uuid: UUID
+    published_by: AbstractUser | None
+    published_at: datetime
+    contributors: list[LibraryHistoryContributor]  # distinct authors of versions in this group
+    # Each element is one entity the user directly requested to publish.
+    # Pre-Verawood: single approximated entry derived from the group's entity.
+    # Post-Verawood: one entry per direct=True record in the PublishLog.
+    direct_published_entities: list[DirectPublishedEntity]
+    # Key to pass as scope_entity_key when fetching entries for this group.
+    # Pre-Verawood: the specific entity key for this group (container or usage key).
+    # Post-Verawood container groups: None — frontend must use currentContainerKey.
+    # Component history (all eras): usage_key.
+    scope_entity_key: LibraryUsageLocatorV2 | LibraryContainerLocator | None
+
+
 @dataclass(frozen=True)
 class LibraryXBlockStaticFile:
     """
@@ -76,3 +168,85 @@ class LibraryXBlockStaticFile:
     url: str
     # Size in bytes
     size: int
+
+
+
+def get_entity_item_type(entity) -> str:
+    """
+    Return the item type string for a PublishableEntity (component or container).
+    """
+    if hasattr(entity, 'component'):
+        return entity.component.component_type.name
+    if hasattr(entity, 'container'):
+        return entity.container.container_type.type_code
+    raise ValueError(f"Entity {entity} is neither a component nor a container.")
+
+
+def make_contributor(user, request=None) -> LibraryHistoryContributor | None:
+    """
+    Convert a single User (or None) to a LibraryHistoryContributor.
+
+    None input produces None output — frontend renders as default/anonymous.
+    """
+    return LibraryHistoryContributor.from_user(user, request) if user else None
+
+
+def resolve_change_action(
+    old_version: PublishableEntityVersion | None,
+    new_version: PublishableEntityVersion | None,
+) -> str:
+    """
+    Derive a human-readable action label from a draft history record's versions.
+    """
+    if old_version is None:
+        return "created"
+    if new_version is None:
+        return "deleted"
+    if old_version.title != new_version.title:
+        return "renamed"
+    return "edited"
+
+
+def direct_published_entity_from_record(
+    record: PublishLogRecord,
+    lib_key: LibraryLocatorV2,
+) -> DirectPublishedEntity:
+    """
+    Build a DirectPublishedEntity from a PublishLogRecord.
+
+    lib_key is used only to construct locator strings — entity_key is always
+    derived from record.entity itself, never from an external container key.
+
+    Callers must ensure the record is fetched with:
+        select_related(
+            'entity__component__component_type',
+            'entity__container__container_type',
+            'new_version',
+            'old_version',
+        )
+    """
+    # Import here to avoid circular imports (container_metadata imports block_metadata).
+    from .container_metadata import library_container_locator  # noqa: PLC0415
+
+    # Use new_version title when available; fall back to old_version for soft-deletes (new_version=None).
+    version = record.new_version or record.old_version
+    title = version.title if version else ""
+    if hasattr(record.entity, 'component'):
+        component = record.entity.component
+        return DirectPublishedEntity(
+            entity_key=LibraryUsageLocatorV2(  # type: ignore[abstract]
+                lib_key=lib_key,
+                block_type=component.component_type.name,
+                usage_id=component.component_code,
+            ),
+            title=title,
+            entity_type=component.component_type.name,
+        )
+    if hasattr(record.entity, 'container'):
+        container = record.entity.container
+        return DirectPublishedEntity(
+            entity_key=library_container_locator(lib_key, container),
+            title=title,
+            entity_type=container.container_type.type_code,
+        )
+    raise ValueError(f"PublishableEntity {record.entity.pk!r} is neither a Component nor a Container")