Error while saving a non-initialized JsonProperty

[eyalhei]

google-cloud-ndb==0.1.0

code example:

from google.cloud import ndb
with get_datastore_context():
 class Test(ndb.Model):
 prop = ndb.JsonProperty(compressed=True, json_type=dict)

 a = Test()
 a.put()

I get an exception:

Traceback (most recent call last):
 a.put()
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/_options.py", line 91, in wrapper
 return wrapped(*pass_args, _options=_options, **kwargs)
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/model.py", line 4917, in _put
 return self._put_async(_options=_options).result()
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/tasklets.py", line 190, in result
 self.check_success()
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/tasklets.py", line 137, in check_success
 raise self._exception
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/tasklets.py", line 293, in _advance_tasklet
 yielded = self.generator.send(send_value)
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/model.py", line 4974, in put
 ds_entity = _entity_to_ds_entity(self)
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/model.py", line 718, in _entity_to_ds_entity
 names = prop._to_datastore(entity, data)
 File "<venv>/lib/python3.7/site-packages/google/cloud/ndb/model.py", line 2482, in _to_datastore
 if not value.startswith(_ZLIB_COMPRESSION_MARKER):
AttributeError: 'NoneType' object has no attribute 'startswith'

Thanks for your awesome work!

[cguardia]

I created a PR for this. Should be merged in a couple of days. Thanks a lot for helping us find and fix these issues.

#200

[cguardia]

Fixed via #200.

[eyalhei]

Hi, I know you just released a version lately, but is there any chance this fix be released soon?