Fix prolearn bug for existing resources whose urls have changed

learning_resources/etl/loaders.py

@@ -301,7 +301,7 @@ def load_run(
     return learning_resource_run
 
 
-def upsert_course_or_program(
+def upsert_course_or_program(  # noqa: C901
     resource_data: dict,
     blocklist: list[str],
     duplicates: list[dict],
@@ -388,9 +388,25 @@ def upsert_course_or_program(
             platform=platform,
             resource_type=LearningResourceType.course.name,
         ).order_by("-updated_on")
-        if existing_courses.count() > 1:
+        if existing_courses.count() > 0:
             for course in existing_courses[1:]:
                 resource_delete_actions(course)
+        # does a resource with the same readable id already exist?
+        # if so, update it with the new unique field value
+        elif LearningResource.objects.filter(
+            readable_id=resource_data["readable_id"],
+            platform=platform,
+            resource_type=LearningResourceType.course.name,
+        ).exists():
+            resource_data[unique_field_name] = unique_field_value
+            unique_field_name = READABLE_ID_FIELD
+            unique_field_value = resource_data.pop(READABLE_ID_FIELD)
+        return LearningResource.objects.select_for_update().update_or_create(
+            **{unique_field_name: unique_field_value},
+            platform=platform,
+            resource_type=resource_type,
+            defaults=resource_data,
+        )
     else:
         unique_field_value = resource_id
     return LearningResource.objects.select_for_update().update_or_create(

learning_resources/etl/loaders_test.py

@@ -627,6 +627,46 @@ def test_load_course_unique_urls(unique_url):
     assert old_course == result
 
 
+def test_load_course_old_id_new_url():
+    """
+    If url is supposed to be unique field, and a resource with the same readable_id
+    but different url exists, that resource should be updated with the new url.
+    """
+    unique_url = "https://mit.edu/unique.html"
+    readable_id = "new_unique_course_id"
+    platform = LearningResourcePlatformFactory.create(code=PlatformType.ocw.name)
+    existing_course = LearningResourceFactory.create(
+        readable_id=readable_id,
+        url="https://mit.edu/old.html",
+        platform=platform,
+        is_course=True,
+    )
+    props = {
+        "readable_id": readable_id,
+        "platform": PlatformType.ocw.name,
+        "offered_by": {"code": OfferedBy.ocw.name},
+        "title": "New title",
+        "url": unique_url,
+        "description": "something",
+        "unique_field": "url",
+        "runs": [
+            {
+                "run_id": "run_id",
+                "enrollment_start": "2024-01-01T00:00:00Z",
+                "start_date": "2024-01-20T00:00:00Z",
+                "end_date": "2024-06-20T00:00:00Z",
+            }
+        ],
+    }
+    result = load_course(props, [], [])
+    assert result.readable_id == readable_id
+    assert result.url == unique_url
+    assert result.published is True
+    existing_course.refresh_from_db()
+    assert existing_course.url == unique_url
+    assert existing_course.readable_id == readable_id
+
+
 @pytest.mark.parametrize("course_exists", [True, False])
 def test_load_course_fetch_only(mocker, course_exists):
     """When fetch_only is True, course should just be fetched from db"""