Error raised when using embedded with nested dict.

[pramos12]

Expected Behavior

Using following schemas:

brands = {
    "item_title": "brand",
    "schema": {
        "name": {"type": "string"},
        "address": "string",
    }
}

components = {
    "item_title": "component",
    "schema": {
        "name": {"type": "string"},
        "price": "integer",
        "brand": {"type": "objectid", "data_relation": {"resource": "brands"}},
    }
}

computers = {
    "item_title": "computers",
    "schema": {
        "name": {"type": "string"},
        "components": {
            "type": "dict",
            "schema": {
                "cpu": {"type": "objectid", "data_relation": {"resource": "components"}},
                "motherboard": {"type": "objectid", "data_relation": {"resource": "components"}},
            }
        }
    }
}

Making the following request:

/computers/5f8e82e3b51714d566994c13?embedded={"components.cpu": 1, "components.motherboard": 1, "components.cpu.brand": 1, "components.motherboard.brand": 1} [GET]

Should provide results with embedded documents

Actual Behavior

Error is raised:

-------------------------------------------------- Captured log call --------------------------------------------------
ERROR    eve:app.py:1891 Exception on /computers/5f8e82e3b51714d566994c13/ [GET]
Traceback (most recent call last):
  File "c:\dev\github\eve\env\lib\site-packages\flask\app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "c:\dev\github\eve\env\lib\site-packages\flask\app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "c:\dev\github\eve\env\lib\site-packages\flask\app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "c:\dev\github\eve\env\lib\site-packages\flask\_compat.py", line 39, in reraise
    raise value
  File "c:\dev\github\eve\env\lib\site-packages\flask\app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "c:\dev\github\eve\env\lib\site-packages\flask\app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\dev\github\eve\eve\endpoints.py", line 94, in item_endpoint
    response = getitem(resource, **lookup)
  File "C:\dev\github\eve\eve\methods\common.py", line 325, in rate_limited
    return f(*args, **kwargs)
  File "C:\dev\github\eve\eve\auth.py", line 80, in decorated
    return f(*args, **kwargs)
  File "C:\dev\github\eve\eve\methods\common.py", line 1369, in decorated
    r = f(resource, **combined_args)
  File "C:\dev\github\eve\eve\methods\get.py", line 321, in getitem
    return getitem_internal(resource, **lookup)
  File "C:\dev\github\eve\eve\methods\get.py", line 414, in getitem_internal
    build_response_document(document, resource, embedded_fields, latest_doc)
  File "C:\dev\github\eve\eve\methods\common.py", line 673, in build_response_document
    resolve_embedded_documents(document, resource, embedded_fields)
  File "C:\dev\github\eve\eve\methods\common.py", line 1110, in resolve_embedded_documents
    for subdocument in subdocuments(fields_chain[:-1], resource, document):
  File "C:\dev\github\eve\eve\methods\common.py", line 1066, in subdocuments
    for result in subdocuments(fields_chain[1:], resource, doc):
  File "C:\dev\github\eve\eve\methods\common.py", line 1059, in subdocuments
    resource = field_definition(resource, fields_chain[0])["data_relation"][
TypeError: 'NoneType' object is not subscriptable

Environment

• Python version: 3.8.x
• Eve version: 1.1.3