fix: Transcripts in downstream creation [FC-0076] (#36509)

* Fix the issue described in https://github.com/openedx/frontend-app-authoring/issues/1352#issuecomment-2791305416

cms/djangoapps/contentstore/helpers.py

@@ -298,6 +298,8 @@ def _insert_static_files_into_downstream_xblock(
         static_files=static_files,
         usage_key=downstream_xblock.usage_key,
     )
+    # FIXME: This code shouldn't have any special cases for specific block types like video
+    # in the future.
     if downstream_xblock.usage_key.block_type == 'video':
         _import_transcripts(
             downstream_xblock,
@@ -390,6 +392,14 @@ def import_static_assets_for_library_sync(downstream_xblock: XBlock, lib_block:
     store = modulestore()
     try:
         with store.bulk_operations(downstream_xblock.context_key):
+            # FIXME: This code shouldn't have any special cases for specific block types like video
+            # in the future.
+            if downstream_xblock.usage_key.block_type == 'video' and not downstream_xblock.edx_video_id:
+                # If the `downstream_xblock` is a new created block, we need to create
+                # a new `edx_video_id` to import the transcripts.
+                downstream_xblock.edx_video_id = create_external_video(display_name='external video')
+                store.update_item(downstream_xblock, request.user.id)
+
             # Now handle static files that need to go into Files & Uploads.
             # If the required files already exist, nothing will happen besides updating the olx.
             notices = _insert_static_files_into_downstream_xblock(downstream_xblock, staged_content.id, request)

cms/djangoapps/contentstore/rest_api/v2/views/tests/test_downstreams.py

@@ -3,14 +3,17 @@ Unit tests for /api/contentstore/v2/downstreams/* JSON APIs.
 """
 import json
 from datetime import datetime, timezone
-from unittest.mock import patch
+from unittest.mock import patch, MagicMock
 
 from django.conf import settings
+from django.urls import reverse
 from freezegun import freeze_time
 from organizations.models import Organization
 
 from cms.djangoapps.contentstore.helpers import StaticFileNotices
 from cms.lib.xblock.upstream_sync import BadUpstream, UpstreamLink
+from cms.djangoapps.contentstore.tests.utils import CourseTestCase
+from opaque_keys.edx.keys import UsageKey
 from common.djangoapps.student.tests.factories import UserFactory
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
@@ -329,6 +332,60 @@ class _DownstreamSyncViewTestMixin(SharedErrorTestCases):
         assert "is not linked" in response.data["developer_message"][0]
 
 
+class CreateDownstreamViewTest(CourseTestCase, _BaseDownstreamViewTestMixin, SharedModuleStoreTestCase):
+    """
+    Tests create new downstream blocks
+    """
+    def call_api_post(self, library_content_key, category):
+        """
+        Call the api to create a downstream block using
+        `library_content_key` as upstream
+        """
+        data = {
+            "parent_locator": str(self.course.location),
+            "display_name": "Test block",
+            "library_content_key": library_content_key,
+            "category": category,
+        }
+        return self.client.post(
+            reverse("xblock_handler"),
+            data=json.dumps(data),
+            content_type="application/json",
+        )
+
+    def test_200(self):
+        response = self.call_api_post(self.html_lib_id, "html")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["upstreamRef"] == self.html_lib_id
+
+        usage_key = UsageKey.from_string(data["locator"])
+        item = modulestore().get_item(usage_key)
+        assert item.upstream == self.html_lib_id
+
+    @patch("cms.djangoapps.contentstore.helpers._insert_static_files_into_downstream_xblock")
+    @patch("cms.djangoapps.contentstore.helpers.content_staging_api.stage_xblock_temporarily")
+    @patch("cms.djangoapps.contentstore.xblock_storage_handlers.view_handlers.sync_from_upstream")
+    def test_200_video(self, mock_sync, mock_stage, mock_insert):
+        mock_lib_block = MagicMock()
+        mock_lib_block.runtime.get_block_assets.return_value = ['mocked_asset']
+        mock_sync.return_value = mock_lib_block
+        mock_stage.return_value = MagicMock()
+        mock_insert.return_value = StaticFileNotices()
+
+        response = self.call_api_post(self.video_lib_id, "video")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["upstreamRef"] == self.video_lib_id
+
+        usage_key = UsageKey.from_string(data["locator"])
+        item = modulestore().get_item(usage_key)
+        assert item.upstream == self.video_lib_id
+        assert item.edx_video_id is not None
+
+
 class PostDownstreamSyncViewTest(_DownstreamSyncViewTestMixin, SharedModuleStoreTestCase):
     """
     Test that `POST /api/v2/contentstore/downstreams/.../sync` initiates a sync from the linked upstream.