Add Field.stores_model_instance

Author: timgraham

django_mongodb_backend/compiler.py

@@ -746,7 +746,7 @@ def execute_sql(self, result_type):
  elif hasattr(value, "prepare_database_save"):
  if field.remote_field:
  value = value.prepare_database_save(field)
- elif not hasattr(field, "embedded_model"):
+ elif not getattr(field, "stores_model_instance", False):
  raise TypeError(
  f"Tried to update field {field} with a model "
  f"instance, {value!r}. Use a value compatible with "

django_mongodb_backend/fields/embedded_model.py

@@ -12,6 +12,8 @@
 class EmbeddedModelField(models.Field):
  """Field that stores a model instance."""
 
+ stores_model_instance = True
+
  def __init__(self, embedded_model, *args, **kwargs):
  """
  `embedded_model` is the model class of the instance to be stored.