Work around for split not having a coherent way to work with/track updated versions of structures

cms/djangoapps/contentstore/tests/test_crud.py

@@ -208,8 +208,6 @@ class TemplateTests(unittest.TestCase):
         # The draft course root has 2 revisions: the published revision, and then the subsequent
         # changes to the draft revision
         version_history = self.split_store.get_block_generations(test_course.location)
-        # Base calculations on the draft revision, not the initial published revision
-        version_history = version_history.children[0]
         self.assertEqual(version_history.locator.version_guid, test_course.location.version_guid)
         self.assertEqual(len(version_history.children), 1)
         self.assertEqual(version_history.children[0].children, [])

common/lib/xmodule/xmodule/modulestore/split_migrator.py

@@ -67,13 +67,16 @@ class SplitMigrator(object):
                 **kwargs
             )
 
-            with self.split_modulestore.bulk_write_operations(new_course.id):
-                self._copy_published_modules_to_course(
-                    new_course, original_course.location, source_course_key, user_id, **kwargs
-                )
+            self._copy_published_modules_to_course(
+                new_course, original_course.location, source_course_key, user_id, **kwargs
+            )
+
+        # TODO: This should be merged back into the above transaction, but can't be until split.py
+        # is refactored to have more coherent access patterns
+        with self.split_modulestore.bulk_write_operations(new_course_key):
 
-                # create a new version for the drafts
-                self._add_draft_modules_to_course(new_course.location, source_course_key, user_id, **kwargs)
+            # create a new version for the drafts
+            self._add_draft_modules_to_course(new_course.location, source_course_key, user_id, **kwargs)
 
         return new_course.id
 
@@ -81,7 +84,7 @@ class SplitMigrator(object):
         """
         Copy all of the modules from the 'direct' version of the course to the new split course.
         """
-        course_version_locator = new_course.id
+        course_version_locator = new_course.id.replace(version_guid=None)
 
         # iterate over published course elements. Wildcarding rather than descending b/c some elements are orphaned (e.g.,
         # course about pages, conditionals)

common/lib/xmodule/xmodule/modulestore/split_mongo/split.py

@@ -113,10 +113,6 @@ class BulkWriteRecord(object):
         self.structures = {}
         self.structures_in_db = set()
 
-        # This stores the set of branches for whom version_structure
-        # has been called
-        self.dirty_branches = set()
-
     @property
     def active(self):
         """
@@ -143,13 +139,37 @@ class BulkWriteRecord(object):
         """
         return self._active_count == 1
 
+    # TODO: This needs to track which branches have actually been modified/versioned,
+    # so that copying one branch to another doesn't update the original branch.
+    @property
+    def dirty_branches(self):
+        """
+        Return a list of which branch version ids differ from what was stored
+        in the database at the beginning of this bulk operation.
+        """
+        # If no course index has been set, then no branches have changed
+        if self.index is None:
+            return []
+
+        # If there was no index in the database to start with, then all branches
+        # are dirty by definition
+        if self.initial_index is None:
+            return self.index.get('versions', {}).keys()
+
+        # Return branches whose ids differ between self.index and self.initial_index
+        return [
+            branch
+            for branch, _id
+            in self.index.get('versions', {}).items()
+            if self.initial_index.get('versions', {}).get(branch) != _id
+        ]
+
     def structure_for_branch(self, branch):
         return self.structures.get(self.index.get('versions', {}).get(branch))
 
     def set_structure_for_branch(self, branch, structure):
         self.index.get('versions', {})[branch] = structure['_id']
         self.structures[structure['_id']] = structure
-        self.dirty_branches.add(branch)
 
     def __repr__(self):
         return u"BulkWriteRecord<{!r}, {!r}, {!r}, {!r}, {!r}>".format(

common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py

@@ -714,10 +714,10 @@ class TestMixedModuleStore(unittest.TestCase):
     #        - load vertical
     #        - load inheritance data
 
-    # TODO: LMS-11220: Document why draft send count is 5
+    # TODO: LMS-11220: Document why draft send count is 6
     # TODO: LMS-11220: Document why draft find count is 18
     # TODO: LMS-11220: Document why split find count is 16
-    @ddt.data(('draft', [19, 5], 0), ('split', [2, 2], 0))
+    @ddt.data(('draft', [19, 6], 0), ('split', [2, 2], 0))
     @ddt.unpack
     def test_path_to_location(self, default_ms, num_finds, num_sends):
         """