def publish_doctree(source, logger):
# type: (str, Any) -> Node
pub = Publisher(reader=None,
parser=None,
writer=None,
settings=None,
source_class=io.StringInput,
destination_class=io.NullOutput)
pub.reader = Reader(None, 'restructuredtext')
pub.reader.doc_logger = logger
pub.set_writer('null')
pub.parser = pub.reader.parser
pub.process_programmatic_settings(None, None, None)
pub.set_source(source, None)
pub.set_destination(None, None)
output = pub.publish(enable_exit_status=False)
return pub.document
