Query.fetch() w/o limit returns different results than w/ large limit.

[tseaver]

[dhermes]

Example:

>>> from gcloud import datastore
>>> from gcloud.datastore.entity import Entity
>>> from gcloud.datastore.key import Key
>>> from gcloud.datastore.query import Query
>>>
>>> datastore.set_default_connection()
>>> datastore.set_default_dataset(dataset_id='foo')
>>>
>>> q = Query(kind='Post')
>>> list(q.fetch(limit=0))
>>> []
>>>
>>> e = Entity(key=Key('Post'))
>>> e['foo'] = 'bar'
>>> e.save()
>>> e.key
<Key[{'kind': 'Post', 'id': 5021553624350720L}], dataset=foo>
>>>
>>> list(q.fetch())
[]
>>>
>>> list(q.fetch(limit=0))
[]
>>>
>>> list(q.fetch(limit=2))
[<Entity[{'kind': u'Post', 'id': 5021553624350720L}] {u'foo': 'bar'}>]

[dhermes]

Also note – per our previous discussion about this – offset has a default while limit does not.

[dhermes]

Also, something which may help us in the future

>>> from gcloud.datastore import datastore_v1_pb2 as datastore_pb
>>> limit_field = datastore_pb.Query.DESCRIPTOR.fields_by_name['limit']
>>> offset_field = datastore_pb.Query.DESCRIPTOR.fields_by_name['offset']
>>> offset_field.has_default_value
True
>>> limit_field.has_default_value
False
>>> offset_field.default_value
0