Merge branch 'release'

Conflict in import because someone had added an import in master that
was not in the release.

Conflicts:
	common/lib/xmodule/xmodule/modulestore/tests/test_xml_importer.py

common/lib/xmodule/xmodule/modulestore/__init__.py

@@ -352,16 +352,21 @@ class EditInfo(object):
         self.original_usage = edit_info.get('original_usage', None)
         self.original_usage_version = edit_info.get('original_usage_version', None)
 
-    def __str__(self):
-        return ("EditInfo(previous_version={0.previous_version}, "
-                "update_version={0.update_version}, "
-                "source_version={0.source_version}, "
-                "edited_on={0.edited_on}, "
-                "edited_by={0.edited_by}, "
-                "original_usage={0.original_usage}, "
-                "original_usage_version={0.original_usage_version}, "
-                "_subtree_edited_on={0._subtree_edited_on}, "
-                "_subtree_edited_by={0._subtree_edited_by})").format(self)
+    def __repr__(self):
+        # pylint: disable=bad-continuation, redundant-keyword-arg
+        return ("{classname}(previous_version={self.previous_version}, "
+                "update_version={self.update_version}, "
+                "source_version={source_version}, "
+                "edited_on={self.edited_on}, "
+                "edited_by={self.edited_by}, "
+                "original_usage={self.original_usage}, "
+                "original_usage_version={self.original_usage_version}, "
+                "_subtree_edited_on={self._subtree_edited_on}, "
+                "_subtree_edited_by={self._subtree_edited_by})").format(
+            self=self,
+            classname=self.__class__.__name__,
+            source_version="UNSET" if self.source_version is None else self.source_version,
+        )  # pylint: disable=bad-continuation
 
 
 class BlockData(object):
@@ -408,13 +413,17 @@ class BlockData(object):
         # EditInfo object containing all versioning/editing data.
         self.edit_info = EditInfo(**block_data.get('edit_info', {}))
 
-    def __str__(self):
-        return ("BlockData(fields={0.fields}, "
-                "block_type={0.block_type}, "
-                "definition={0.definition}, "
-                "definition_loaded={0.definition_loaded}, "
-                "defaults={0.defaults}, "
-                "edit_info={0.edit_info})").format(self)
+    def __repr__(self):
+        # pylint: disable=bad-continuation, redundant-keyword-arg
+        return ("{classname}(fields={self.fields}, "
+                "block_type={self.block_type}, "
+                "definition={self.definition}, "
+                "definition_loaded={self.definition_loaded}, "
+                "defaults={self.defaults}, "
+                "edit_info={self.edit_info})").format(
+            self=self,
+            classname=self.__class__.__name__,
+        )  # pylint: disable=bad-continuation
 
 
 new_contract('BlockData', BlockData)

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

@@ -2831,6 +2831,8 @@ class SplitMongoModuleStore(SplitBulkWriteMixin, ModuleStoreWriteBase):
             # perhaps replace by fixing the views or Field Reference*.from_json to return a Key
             if isinstance(reference, basestring):
                 reference = BlockUsageLocator.from_string(reference)
+            elif isinstance(reference, BlockKey):
+                return reference
             return BlockKey.from_usage_key(reference)
 
         for field_name, value in fields.iteritems():

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

@@ -494,11 +494,14 @@ class DraftVersioningModuleStore(SplitMongoModuleStore, ModuleStoreDraftAndPubli
                 block_id = self.DEFAULT_ROOT_LIBRARY_BLOCK_ID
             new_usage_key = course_key.make_usage_key(block_type, block_id)
 
+            # Only the course import process calls import_xblock(). If the branch setting is published_only,
+            # then the non-draft blocks are being imported.
             if self.get_branch_setting() == ModuleStoreEnum.Branch.published_only:
-                # override existing draft (PLAT-297, PLAT-299). NOTE: this has the effect of removing
-                # any local changes w/ the import.
+                # Override any existing drafts (PLAT-297, PLAT-299). This import/publish step removes
+                # any local changes during the course import.
                 draft_course = course_key.for_branch(ModuleStoreEnum.BranchName.draft)
                 with self.branch_setting(ModuleStoreEnum.Branch.draft_preferred, draft_course):
+                    # Importing the block and publishing the block links the draft & published blocks' version history.
                     draft_block = self.import_xblock(user_id, draft_course, block_type, block_id, fields, runtime)
                     return self.publish(draft_block.location.version_agnostic(), user_id, blacklist=EXCLUDE_ALL, **kwargs)
 

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

@@ -10,7 +10,7 @@ from xmodule.x_module import XModuleMixin
 from opaque_keys.edx.locations import Location
 from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.inheritance import InheritanceMixin
-from xmodule.modulestore.xml_importer import _import_module_and_update_references, _update_module_location
+from xmodule.modulestore.xml_importer import _update_and_import_module, _update_module_location
 from xmodule.modulestore.tests.mongo_connection import MONGO_PORT_NUM, MONGO_HOST
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from xmodule.tests import DATA_DIR
@@ -145,7 +145,7 @@ class RemapNamespaceTest(ModuleStoreNoSettings):
 
         # Move to different runtime w/ different course id
         target_location_namespace = SlashSeparatedCourseKey("org", "course", "run")
-        new_version = _import_module_and_update_references(
+        new_version = _update_and_import_module(
             self.xblock,
             modulestore(),
             999,
@@ -182,7 +182,7 @@ class RemapNamespaceTest(ModuleStoreNoSettings):
 
         # Remap the namespace
         target_location_namespace = Location("org", "course", "run", "category", "stubxblock")
-        new_version = _import_module_and_update_references(
+        new_version = _update_and_import_module(
             self.xblock,
             modulestore(),
             999,
@@ -214,7 +214,7 @@ class RemapNamespaceTest(ModuleStoreNoSettings):
 
         # Remap the namespace
         target_location_namespace = Location("org", "course", "run", "category", "stubxblock")
-        new_version = _import_module_and_update_references(
+        new_version = _update_and_import_module(
             self.xblock,
             modulestore(),
             999,

common/lib/xmodule/xmodule/modulestore/xml_exporter.py

@@ -42,6 +42,9 @@ def _export_drafts(modulestore, course_key, export_fs, xml_centric_course_key):
             qualifiers={'category': {'$nin': DIRECT_ONLY_CATEGORIES}},
             revision=ModuleStoreEnum.RevisionOption.draft_only
         )
+        # Check to see if the returned draft modules have changes w.r.t. the published module.
+        # Only modules with changes will be exported into the /drafts directory.
+        draft_modules = [module for module in draft_modules if modulestore.has_changes(module)]
 
         if draft_modules:
             draft_course_dir = export_fs.makeopendir(DRAFT_DIR)
@@ -153,20 +156,15 @@ class ExportManager(object):
         Perform the export given the parameters handed to this class at init.
         """
         with self.modulestore.bulk_operations(self.courselike_key):
-            # depth = None: Traverses down the entire course structure.
-            # lazy = False: Loads and caches all block definitions during traversal for fast access later
-            #               -and- to eliminate many round-trips to read individual definitions.
-            # Why these parameters? Because a course export needs to access all the course block information
-            # eventually. Accessing it all now at the beginning increases performance of the export.
-            fsm = OSFS(self.root_dir)
-            courselike = self.get_courselike()
-            export_fs = courselike.runtime.export_fs = fsm.makeopendir(self.target_dir)
-            root_courselike_dir = self.root_dir + '/' + self.target_dir
 
+            fsm = OSFS(self.root_dir)
             root = lxml.etree.Element('unknown')  # pylint: disable=no-member
 
             # export only the published content
             with self.modulestore.branch_setting(ModuleStoreEnum.Branch.published_only, self.courselike_key):
+                courselike = self.get_courselike()
+                export_fs = courselike.runtime.export_fs = fsm.makeopendir(self.target_dir)
+
                 # change all of the references inside the course to use the xml expected key type w/o version & branch
                 xml_centric_courselike_key = self.get_key()
                 adapt_references(courselike, xml_centric_courselike_key, export_fs)
@@ -176,6 +174,7 @@ class ExportManager(object):
             self.process_root(root, export_fs)
 
             # Process extra items-- drafts, assets, etc
+            root_courselike_dir = self.root_dir + '/' + self.target_dir
             self.process_extra(root, courselike, root_courselike_dir, xml_centric_courselike_key, export_fs)
 
             # Any last pass adjustments
@@ -192,6 +191,11 @@ class CourseExportManager(ExportManager):
         )
 
     def get_courselike(self):
+        # depth = None: Traverses down the entire course structure.
+        # lazy = False: Loads and caches all block definitions during traversal for fast access later
+        #               -and- to eliminate many round-trips to read individual definitions.
+        # Why these parameters? Because a course export needs to access all the course block information
+        # eventually. Accessing it all now at the beginning increases performance of the export.
         return self.modulestore.get_course(self.courselike_key, depth=None, lazy=False)
 
     def process_root(self, root, export_fs):