on import, when enumerating through the 'draft content', OSX environments will…

on import, when enumerating through the 'draft content', OSX environments will have hidden binary encoded quarantine files. We don't want to try to process these as they will throw an exception when trying to be parsed. It's harmless - the import goes on fine - but it's a lot of clutter in the output logs.

common/lib/xmodule/xmodule/modulestore/xml_importer.py

@@ -242,9 +242,37 @@ def import_course_draft(xml_module_store, store, draft_store, course_data_path,
     for dirname, dirnames, filenames in os.walk(draft_dir + "/vertical"):
         for filename in filenames:
             module_path = os.path.join(dirname, filename)
-            with open(module_path) as f:
+            with open(module_path, 'r') as f:
                 try:
-                    xml = f.read().decode('utf-8')
+                    # note, on local dev it seems like OSX will put some extra files in
+                    # the directory with "quarantine" information. These files are
+                    # binary files and will throw execptions when we try to parse
+                    # the file as an XML string. Let's make sure we're
+                    # dealing with a string before ingesting
+                    data = f.read()
+
+                    try:
+                        xml = data.decode('utf-8')
+                    except UnicodeDecodeError, e:
+                        # seems like on OSX localdev, the OS is making quarantine files
+                        # in the unzip directory when importing courses
+                        # so if we blindly try to enumerate through the directory, we'll try
+                        # to process a bunch of binary quarantine files (which are prefixed with a '._' character
+                        # which will dump a bunch of exceptions to the output, although they are harmless.
+                        #
+                        # Reading online docs there doesn't seem to be a good means to detect a 'hidden'
+                        # file that works well across all OS environments. So for now, I'm using
+                        # OSX's utilization of a leading '.' in the filename to indicate a system hidden
+                        # file.
+                        #
+                        # Better yet would be a way to figure out if this is a binary file, but I
+                        # haven't found a good way to do this yet.
+                        #
+                        if filename.startswith('.'):
+                            continue
+                        # Not a 'hidden file', then re-raise exception
+                        raise e
+
                     descriptor = system.process_xml(xml)
 
                     def _import_module(module):