Fix metadata inheritance

* with xml datastore, re-do all inheritance once the whole course is loaded

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

@@ -55,6 +55,9 @@ class CachingDescriptorSystem(MakoDescriptorSystem):
         if json_data is None:
             return self.modulestore.get_item(location)
         else:
+            # TODO (vshnayder): metadata inheritance is somewhat broken because mongo, doesn't
+            # always load an entire course.  We're punting on this until after launch, and then
+            # will build a proper course policy framework.
             return XModuleDescriptor.load_from_json(json_data, self, self.default_class)
 
 

common/lib/xmodule/xmodule/modulestore/xml.py

@@ -213,6 +213,12 @@ class XMLModuleStore(ModuleStoreBase):
             system = ImportSystem(self, org, course, course_dir, tracker)
 
             course_descriptor = system.process_xml(etree.tostring(course_data))
+            # NOTE: The descriptors end up loading somewhat bottom up, which
+            # breaks metadata inheritance via get_children().  Instead
+            # (actually, in addition to, for now), we do a final inheritance pass
+            # after we have the course descriptor.
+            XModuleDescriptor.compute_inherited_metadata(course_descriptor)
+
             log.debug('========> Done with course import from {0}'.format(course_dir))
             return course_descriptor
 

common/lib/xmodule/xmodule/tests/test_import.py

@@ -8,8 +8,11 @@ from xmodule.x_module import XMLParsingSystem, XModuleDescriptor
 from xmodule.xml_module import is_pointer_tag
 from xmodule.errortracker import make_error_tracker
 from xmodule.modulestore import Location
+from xmodule.modulestore.xml import XMLModuleStore
 from xmodule.modulestore.exceptions import ItemNotFoundError
 
+from .test_export import DATA_DIR
+
 ORG = 'test_org'
 COURSE = 'test_course'
 
@@ -185,3 +188,22 @@ class ImportTestCase(unittest.TestCase):
             chapter_xml = etree.fromstring(f.read())
         self.assertEqual(chapter_xml.tag, 'chapter')
         self.assertFalse('graceperiod' in chapter_xml.attrib)
+
+    def test_metadata_inherit(self):
+        """Make sure that metadata is inherited properly"""
+
+        print "Starting import"
+        initial_import = XMLModuleStore(DATA_DIR, eager=True, course_dirs=['toy'])
+
+        courses = initial_import.get_courses()
+        self.assertEquals(len(courses), 1)
+        course = courses[0]
+
+        def check_for_key(key, node):
+            "recursive check for presence of key"
+            print "Checking {}".format(node.location.url())
+            self.assertTrue(key in node.metadata)
+            for c in node.get_children():
+                check_for_key(key, c)
+
+        check_for_key('graceperiod', course)

common/lib/xmodule/xmodule/x_module.py

@@ -403,6 +403,21 @@ class XModuleDescriptor(Plugin, HTMLSnippet):
         return dict((k,v) for k,v in self.metadata.items()
                     if k not in self._inherited_metadata)
 
+    @staticmethod
+    def compute_inherited_metadata(course):
+        """Given a course descriptor, traverse the entire course tree and do
+        metadata inheritance.  Should be called after importing a course.
+
+        NOTE: This means that there is no such thing as lazy loading at the
+        moment--this accesses all the children."""
+        def do_inherit(node):
+            for c in node.get_children():
+                c.inherit_metadata(node.metadata)
+                do_inherit(c)
+
+        do_inherit(course)
+
+
     def inherit_metadata(self, metadata):
         """
         Updates this module with metadata inherited from a containing module.
@@ -415,6 +430,7 @@ class XModuleDescriptor(Plugin, HTMLSnippet):
             if attr not in self.metadata and attr in metadata:
                 self._inherited_metadata.add(attr)
                 self.metadata[attr] = metadata[attr]
+        print "final self.metadata: {}".format(self.metadata)
 
     def get_children(self):
         """Returns a list of XModuleDescriptor instances for the children of
@@ -423,6 +439,9 @@ class XModuleDescriptor(Plugin, HTMLSnippet):
             self._child_instances = []
             for child_loc in self.definition.get('children', []):
                 child = self.system.load_item(child_loc)
+                # TODO (vshnayder): this should go away once we have
+                # proper inheritance support in mongo.  The xml
+                # datastore does all inheritance on course load.
                 child.inherit_metadata(self.metadata)
                 self._child_instances.append(child)