Fix issues with overrides on duplicated RCBs.

cms/djangoapps/contentstore/tests/test_libraries.py

@@ -3,6 +3,7 @@ Content library unit tests that require the CMS runtime.
 """
 from contentstore.tests.utils import AjaxEnabledTestClient, parse_json
 from contentstore.utils import reverse_url, reverse_usage_url, reverse_library_url
+from contentstore.views.item import _duplicate_item
 from contentstore.views.preview import _load_preview_module
 from contentstore.views.tests.test_library import LIBRARY_REST_URL
 import ddt
@@ -726,6 +727,7 @@ class TestLibraryAccess(SignalDisconnectTestMixin, LibraryTestCase):
         self.assertEqual(len(lc_block.children), 1 if expected_result else 0)
 
 
+@ddt.ddt
 class TestOverrides(LibraryTestCase):
     """
     Test that overriding block Scope.settings fields from a library in a specific course works
@@ -822,7 +824,8 @@ class TestOverrides(LibraryTestCase):
         self.assertEqual(self.problem.definition_locator.definition_id, definition_id)
         self.assertEqual(self.problem_in_course.definition_locator.definition_id, definition_id)
 
-    def test_persistent_overrides(self):
+    @ddt.data(False, True)
+    def test_persistent_overrides(self, duplicate):
         """
         Test that when we override Scope.settings values in a course,
         the override values persist even when the block is refreshed
@@ -834,7 +837,14 @@ class TestOverrides(LibraryTestCase):
         self.problem_in_course.weight = new_weight
 
         modulestore().update_item(self.problem_in_course, self.user.id)
-        self.problem_in_course = modulestore().get_item(self.problem_in_course.location)
+        if duplicate:
+            # Check that this also works when the RCB is duplicated.
+            self.lc_block = modulestore().get_item(
+                _duplicate_item(self.course.location, self.lc_block.location, self.user)
+            )
+            self.problem_in_course = modulestore().get_item(self.lc_block.children[0])
+        else:
+            self.problem_in_course = modulestore().get_item(self.problem_in_course.location)
         self.assertEqual(self.problem_in_course.display_name, new_display_name)
         self.assertEqual(self.problem_in_course.weight, new_weight)
 

cms/djangoapps/contentstore/views/item.py

@@ -593,17 +593,27 @@ def _duplicate_item(parent_usage_key, duplicate_source_usage_key, user, display_
             runtime=source_item.runtime,
         )
 
+        handle_children = True
+        handle_parenting = True
+
+        if hasattr(dest_module, 'studio_post_duplicate'):
+            # Allow an XBlock to do anything fancy it may need to when duplicated from another block.
+            # These blocks may handle their own children or parenting if needed. Let them return booleans to
+            # let us know if we need to handle these or not.
+            handle_children, handle_parenting = dest_module.studio_post_duplicate(store, parent_usage_key, source_item)
+
         # Children are not automatically copied over (and not all xblocks have a 'children' attribute).
         # Because DAGs are not fully supported, we need to actually duplicate each child as well.
-        if source_item.has_children:
-            dest_module.children = []
+        if source_item.has_children and handle_children:
+            dest_module.children = dest_module.children or []
             for child in source_item.children:
                 dupe = _duplicate_item(dest_module.location, child, user=user)
                 if dupe not in dest_module.children:  # _duplicate_item may add the child for us.
                     dest_module.children.append(dupe)
             store.update_item(dest_module, user.id)
 
-        if 'detached' not in source_item.runtime.load_block_type(category)._class_tags:
+        # pylint: disable=protected-access
+        if ('detached' not in source_item.runtime.load_block_type(category)._class_tags) and handle_parenting:
             parent = store.get_item(parent_usage_key)
             # If source was already a child of the parent, add duplicate immediately afterward.
             # Otherwise, add child to end.

common/lib/xmodule/xmodule/library_content_module.py

@@ -306,6 +306,29 @@ class LibraryContentDescriptor(LibraryContentFields, MakoModuleDescriptor, XmlDe
         non_editable_fields.extend([LibraryContentFields.mode, LibraryContentFields.source_library_version])
         return non_editable_fields
 
+    def get_tools(self):
+        """
+        Grab the library tools service or raise an error.
+        """
+        lib_tools = self.runtime.service(self, 'library_tools')
+        if not lib_tools:
+            # This error is diagnostic. The user won't see it, but it may be helpful
+            # during debugging.
+            return Response(_(u"Course does not support Library tools."), status=400)
+        return lib_tools
+
+    def get_user_id(self):
+        """
+        Get the ID of the current user.
+        """
+        user_service = self.runtime.service(self, 'user')
+        if user_service:
+            # May be None when creating bok choy test fixtures
+            user_id = user_service.get_current_user().opt_attrs.get('edx-platform.user_id', None)
+        else:
+            user_id = None
+        return user_id
+
     @XBlock.handler
     def refresh_children(self, request=None, suffix=None):  # pylint: disable=unused-argument
         """
@@ -320,21 +343,50 @@ class LibraryContentDescriptor(LibraryContentFields, MakoModuleDescriptor, XmlDe
         the version number of the libraries used, so we easily determine if
         this block is up to date or not.
         """
-        lib_tools = self.runtime.service(self, 'library_tools')
-        if not lib_tools:
-            # This error is diagnostic. The user won't see it, but it may be helpful
-            # during debugging.
-            return Response(_(u"Course does not support Library tools."), status=400)
-        user_service = self.runtime.service(self, 'user')
+        lib_tools = self.get_tools()
         user_perms = self.runtime.service(self, 'studio_user_permissions')
-        if user_service:
-            # May be None when creating bok choy test fixtures
-            user_id = user_service.get_current_user().opt_attrs.get('edx-platform.user_id', None)
-        else:
-            user_id = None
+        user_id = self.get_user_id()
         lib_tools.update_children(self, user_id, user_perms)
         return Response()
 
+    # pylint: disable=unused-argument
+    def studio_post_duplicate(self, store, parent_usage_key, source_block):
+        """
+        Used by the studio after basic duplication of a source block. We handle the children
+        ourselves, because we have to properly reference the library upstream and set the overrides.
+
+        Otherwise we'll end up losing data on the next refresh.
+        """
+        # The first task will be to refresh our copy of the library to generate the children.
+        # We must do this at the currently set version of the library block. Otherwise we may not have
+        # exactly the same children-- someone may be duplicating an out of date block, after all.
+        lib_tools = self.get_tools()
+        user_id = self.get_user_id()
+        user_perms = self.runtime.service(self, 'studio_user_permissions')
+        # pylint: disable=no-member
+        lib_tools.update_children(self, user_id, user_perms, version=self.source_library_version)
+
+        # Copy over any overridden settings the course author may have applied to the blocks.
+        def copy_overrides(source, dest):
+            """
+            Copy any overrides the user has made on blocks in this library.
+            """
+            for field_name in source.fields.keys():
+                field = dest.fields[field_name]
+                if field.scope == Scope.settings and field.is_set_on(source):
+                    setattr(dest, field_name, getattr(source, field_name))
+            if source.has_children:
+                source_children = [store.get_item(source_key) for source_key in source.children]
+                dest_children = [store.get_item(dest_key) for dest_key in dest.children]
+                for source_child, dest_child in zip(source_children, dest_children):
+                    copy_overrides(source_child, dest_child)
+            store.update_item(dest, user_id)
+
+        copy_overrides(source_block, self)
+
+        # Don't handle children. Handle parenting.
+        return False, True
+
     def _validate_library_version(self, validation, lib_tools, version, library_key):
         """
         Validates library version

common/lib/xmodule/xmodule/library_tools.py

@@ -16,16 +16,21 @@ class LibraryToolsService(object):
     def __init__(self, modulestore):
         self.store = modulestore
 
-    def _get_library(self, library_key):
+    def _get_library(self, library_key, version=None):
         """
         Given a library key like "library-v1:ProblemX+PR0B", return the
         'library' XBlock with meta-information about the library.
 
+        A specific version may be specified.
+
         Returns None on error.
         """
         if not isinstance(library_key, LibraryLocator):
             library_key = LibraryLocator.from_string(library_key)
-        assert library_key.version_guid is None
+
+        library_key = LibraryLocator(
+            org=library_key.org, library=library_key.library, branch=library_key.branch, version_guid=version
+        )
 
         try:
             return self.store.get_library(library_key, remove_version=False, remove_branch=False)
@@ -102,7 +107,7 @@ class LibraryToolsService(object):
         """
         return self.store.check_supports(block.location.course_key, 'copy_from_template')
 
-    def update_children(self, dest_block, user_id, user_perms=None):
+    def update_children(self, dest_block, user_id, user_perms=None, version=None):
         """
         This method is to be used when the library that a LibraryContentModule
         references has been updated. It will re-fetch all matching blocks from
@@ -123,7 +128,7 @@ class LibraryToolsService(object):
 
         source_blocks = []
         library_key = dest_block.source_library_key
-        library = self._get_library(library_key)
+        library = self._get_library(library_key, version=version)
         if library is None:
             raise ValueError("Requested library not found.")
         if user_perms and not user_perms.can_read(library_key):