fix an issue in release_feedback where groupshared user could not re-release feedback

Author: Frans Welin

nbgrader/exchange/default/release_feedback.py

@@ -76,9 +76,11 @@ def copy_files(self):
 
             self.log.debug("Unique key is: {}".format(unique_key))
             checksum = notebook_hash(nbfile, unique_key)
-            dest = os.path.join(self.dest_path, "{}.html".format(checksum))
+            dest = os.path.join(self.dest_path, "{}-tmp.html".format(checksum))
 
             self.log.info("Releasing feedback for student '{}' on assignment '{}/{}/{}' ({})".format(
                 student_id, self.coursedir.course_id, self.coursedir.assignment_id, notebook_id, timestamp))
             shutil.copy(html_file, dest)
+            updated_feedback = os.path.join(self.dest_path, "{}.html". format(checksum))
+            shutil.move(dest, updated_feedback)
             self.log.info("Feedback released to: {}".format(dest))