Map field message definitions do not consistently use module alias disambiguation #618
Description
This is visible with Bigtable Admin. The generation produces output and generates no errors, but the generated unit tests fail.
from .bigtable_instance_admin import (CreateInstanceRequest, GetInstanceRequest, ListInstancesRequest, ListInstancesResponse, PartialUpdateInstanceRequest, DeleteInstanceRequest, CreateClusterRequest, GetClusterRequest, ListClustersRequest, ListClustersResponse, DeleteClusterRequest, CreateInstanceMetadata, UpdateInstanceMetadata, CreateClusterMetadata, UpdateClusterMetadata, CreateAppProfileRequest, GetAppProfileRequest, ListAppProfilesRequest, ListAppProfilesResponse, UpdateAppProfileRequest, DeleteAppProfileRequest, UpdateAppProfileMetadata, )
google/cloud/bigtable_admin_v2/types/bigtable_instance_admin.py:55: in <module>
class CreateInstanceRequest(proto.Message):
google/cloud/bigtable_admin_v2/types/bigtable_instance_admin.py:88: in CreateInstanceRequest
message=instance.Cluster,
E AttributeError: 'Field' object has no attribute 'Cluster
In the above stacktrace, message=instance.Cluster should be message=gba_instance.Cluster.