Reverse delete rule not allowed for EmbeddedDocuments

Hi!

I have the following models:

class A(Document):
    name = StringField()

class Embedded(EmbeddedDocument):
    ref = ReferenceField('A', reverse_delete_rule=DENY)

class B(Document):
    children = MapField(EmbeddedDocumentField('Embedded'))

But I obtain the error:

File "/home/.../mongoengine/base/metaclasses.py", line 210, in __new__
    raise InvalidDocumentError(msg)
mongoengine.errors.InvalidDocumentError: Reverse delete rules are not supported for EmbeddedDocuments (field: ref)

What is it due to? Is there a way to bypass this constraint?

Thanks!

Start with the model definitions in the issue and inspect mongoengine/base/metaclasses.py around line 210, where InvalidDocumentError is raised. Trace how reverse delete rules are validated for EmbeddedDocuments and compare that with the documented behavior. Done means establishing whether support is feasible or the constraint should instead be documented clearly.