Add revert_to_published method.

STUD-1860

common/lib/xmodule/xmodule/modulestore/mixed.py

@@ -354,6 +354,19 @@ class MixedModuleStore(ModuleStoreWriteBase):
         store = self._verify_modulestore_support(location, 'delete_item')
         store.delete_item(location, user_id=user_id, **kwargs)
 
+    def revert_to_published(self, location, user_id=None):
+        """
+        Reverts an item to its last published version (recursively traversing all of its descendants).
+        If no published version exists, a VersionConflictError is thrown.
+
+        If a published version exists but there is no draft version of this item or any of its descendants, this
+        method is a no-op.
+
+        :raises InvalidVersionError: if no published version exists for the location specified
+        """
+        store = self._verify_modulestore_support(location, 'revert_to_published')
+        return store.revert_to_published(location, user_id=user_id)
+
     def close_all_connections(self):
         """
         Close all db connections

common/lib/xmodule/xmodule/modulestore/mongo/draft.py

@@ -597,6 +597,51 @@ class DraftModuleStore(MongoModuleStore):
         self._verify_branch_setting(ModuleStoreEnum.Branch.draft_preferred)
         return self._convert_to_draft(location, user_id, delete_published=True)
 
+    def revert_to_published(self, location, user_id=None):
+        """
+        Reverts an item to its last published version (recursively traversing all of its descendants).
+        If no published version exists, a VersionConflictError is thrown.
+
+        If a published version exists but there is no draft version of this item or any of its descendants, this
+        method is a no-op. It is also a no-op if the root item is in DIRECT_ONLY_CATEGORIES.
+
+        :raises InvalidVersionError: if no published version exists for the location specified
+        """
+        self._verify_branch_setting(ModuleStoreEnum.Branch.draft_preferred)
+        _verify_revision_is_published(location)
+
+        if location.category in DIRECT_ONLY_CATEGORIES:
+            return
+
+        if not self.has_item(location, revision=ModuleStoreEnum.RevisionOption.published_only):
+            raise InvalidVersionError(location)
+
+        def delete_draft_only(root_location):
+            """
+            Helper function that calls delete on the specified location if a draft version of the item exists.
+            If no draft exists, this function recursively calls itself on the children of the item.
+            """
+            query = root_location.to_deprecated_son(prefix='_id.')
+            del query['_id.revision']
+            versions_found = self.collection.find(
+                query, {'_id': True, 'definition.children': True}, sort=[SORT_REVISION_FAVOR_DRAFT]
+            )
+            # If 2 versions versions exist, we can assume one is a published version. Go ahead and do the delete
+            # of the draft version.
+            if versions_found.count() > 1:
+                self._delete_subtree(root_location, [as_draft])
+            elif versions_found.count() == 1:
+                # Since this method cannot be called on something in DIRECT_ONLY_CATEGORIES and we call
+                # delete_subtree as soon as we find an item with a draft version, if there is only 1 version
+                # it must be published (since adding a child to a published item creates a draft of the parent).
+                item = versions_found[0]
+                assert item.get('_id').get('revision') != MongoRevisionKey.draft
+                for child in item.get('definition', {}).get('children', []):
+                    child_loc = Location.from_deprecated_string(child)
+                    delete_draft_only(child_loc)
+
+        delete_draft_only(location)
+
     def _query_children_for_cache_children(self, course_key, items):
         # first get non-draft in a round-trip
         to_process_non_drafts = super(DraftModuleStore, self)._query_children_for_cache_children(course_key, items)

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

@@ -1380,6 +1380,18 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         log.info(u"deleting course from split-mongo: %s", course_key)
         self.db_connection.delete_course_index(index)
 
+    def revert_to_published(self, location, user_id=None):
+        """
+        Reverts an item to its last published version (recursively traversing all of its descendants).
+        If no published version exists, a VersionConflictError is thrown.
+
+        If a published version exists but there is no draft version of this item or any of its descendants, this
+        method is a no-op.
+
+        :raises InvalidVersionError: if no published version exists for the location specified
+        """
+        raise NotImplementedError()
+
     def get_errored_courses(self):
         """
         This function doesn't make sense for the mongo modulestore, as structures

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

@@ -9,6 +9,7 @@ from xmodule.tests import DATA_DIR
 from opaque_keys.edx.locations import Location
 from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.exceptions import ItemNotFoundError
+from xmodule.exceptions import InvalidVersionError
 
 from opaque_keys.edx.locator import BlockUsageLocator, CourseLocator
 from xmodule.modulestore.tests.test_location_mapper import LocMapperSetupSansDjango, loc_mapper
@@ -460,6 +461,87 @@ class TestMixedModuleStore(LocMapperSetupSansDjango):
             (child_to_delete, None, ModuleStoreEnum.RevisionOption.published_only),
         ])
 
+
+    @ddt.data('draft')
+    def test_revert_to_published_root_draft(self, default_ms):
+        """
+        Test calling revert_to_published on draft vertical.
+        """
+        self.initdb(default_ms)
+        self._create_block_hierarchy()
+        self.store.publish(self.course.location, self.user_id)
+
+        # delete leaf problem (will make parent vertical a draft)
+        self.store.delete_item(self.problem_x1a_1.location, self.user_id)
+
+        draft_parent = self.store.get_item(self.vertical_x1a.location)
+        self.assertEqual(2, len(draft_parent.children))
+        published_parent = self.store.get_item(
+            self.vertical_x1a.location,
+            revision=ModuleStoreEnum.RevisionOption.published_only
+        )
+        self.assertEqual(3, len(published_parent.children))
+
+        self.store.revert_to_published(self.vertical_x1a.location, self.user_id)
+        reverted_parent = self.store.get_item(self.vertical_x1a.location)
+        self.assertEqual(3, len(published_parent.children))
+        self.assertEqual(reverted_parent, published_parent)
+
+    @ddt.data('draft')
+    def test_revert_to_published_root_published(self, default_ms):
+        """
+        Test calling revert_to_published on a published vertical with a draft child.
+        """
+        self.initdb(default_ms)
+        self._create_block_hierarchy()
+        self.store.publish(self.course.location, self.user_id)
+
+        orig_display_name = self.problem_x1a_1.display_name
+
+        # Change display name of problem and update just it (so parent remains published)
+        self.problem_x1a_1.display_name = "updated before calling revert"
+        self.store.update_item(self.problem_x1a_1, self.user_id)
+        self.store.revert_to_published(self.vertical_x1a.location, self.user_id)
+
+        reverted_problem = self.store.get_item(self.problem_x1a_1.location)
+        self.assertEqual(orig_display_name, reverted_problem.display_name)
+
+    @ddt.data('draft')
+    def test_revert_to_published_no_draft(self, default_ms):
+        """
+        Test calling revert_to_published on vertical with no draft content does nothing.
+        """
+        self.initdb(default_ms)
+        self._create_block_hierarchy()
+        self.store.publish(self.course.location, self.user_id)
+
+        orig_vertical = self.vertical_x1a
+        self.store.revert_to_published(self.vertical_x1a.location, self.user_id)
+        reverted_vertical = self.store.get_item(self.vertical_x1a.location)
+        self.assertEqual(orig_vertical, reverted_vertical)
+
+    @ddt.data('draft')
+    def test_revert_to_published_no_published(self, default_ms):
+        """
+        Test calling revert_to_published on vertical with no published version errors.
+        """
+        self.initdb(default_ms)
+        self._create_block_hierarchy()
+        with self.assertRaises(InvalidVersionError):
+            self.store.revert_to_published(self.vertical_x1a.location)
+
+    @ddt.data('draft')
+    def test_revert_to_published_direct_only(self, default_ms):
+        """
+        Test calling revert_to_published on a direct-only item is a no-op.
+        """
+        self.initdb(default_ms)
+        self._create_block_hierarchy()
+        self.store.revert_to_published(self.sequential_x1.location)
+        reverted_parent = self.store.get_item(self.sequential_x1.location)
+        # It does not discard the child vertical, even though that child is a draft (with no published version)
+        self.assertEqual(1, len(reverted_parent.children))
+
     @ddt.data('draft', 'split')
     def test_get_orphans(self, default_ms):
         self.initdb(default_ms)