This replaces:

• mixing attributes and slots in a single class can cause some forward references not to be quoted in pythongen #1166.

It looks like there are some situations where foward ref detection falsely assumes no forward reference when it should use one

This is because _sort_classes is applied prior to writing classes, but the following code operates over the asserted sort order

this replicates the issue:

id: http://example.org/issue-1168
name: issue_1168
description: Tests forward reference edge case
see_also:
  - https://github.com/linkml/linkml/issues/1168

classes:
  C:
    is_a: D
    attributes:
      d:
        range: D
  D:
    attributes:
      c:
        range: C

the order becomes D, C:

@dataclass
class D(YAMLRoot):
    _inherited_slots: ClassVar[List[str]] = []

    class_class_uri: ClassVar[URIRef] = URIRef("http://example.org/issue-1168/D")
    class_class_curie: ClassVar[str] = None
    class_name: ClassVar[str] = "D"
    class_model_uri: ClassVar[URIRef] = URIRef("http://example.org/issue-1168/D")

    c: Optional[Union[dict, C]] = None
    ...


@dataclass
class C(D):

which yields

NameError: name 'C' is not defined

The workaround is to order elements with your schema accordingly, but this should not be necessary