feat: Implement discriminators knowledge in code generation BNCH-30443

openapi_python_client/parser/properties/__init__.py

@@ -162,6 +162,8 @@ class UnionProperty(Property):
  inner_properties: List[Property]
  template: ClassVar[str] = "union_property.pyi"
  has_properties_without_templates: bool = attr.ib(init=False)
+ discriminator_property: Optional[str]
+ discriminator_mappings: Dict[str, Property]
 
  def __attrs_post_init__(self) -> None:
  super().__attrs_post_init__()
@@ -171,6 +173,8 @@ def __attrs_post_init__(self) -> None:
 
  def _get_inner_type_strings(self, json: bool = False) -> List[str]:
  inner_types = [p.get_type_string(no_optional=True, json=json) for p in self.inner_properties]
+ if not json:
+ inner_types.append("UnknownType")
  unique_inner_types = list(dict.fromkeys(inner_types))
  return unique_inner_types
 
@@ -428,13 +432,27 @@ def build_union_property(
  *, data: oai.Schema, name: str, required: bool, schemas: Schemas, parent_name: str
 ) -> Tuple[Union[UnionProperty, PropertyError], Schemas]:
  sub_properties: List[Property] = []
+ inverted_mappings = {}
+ for k, v in (data.discriminator.mapping if data.discriminator else {}).items():
+ class_name = Reference.from_ref(v).class_name
+ if class_name in inverted_mappings:
+ raise ArgumentError(
+ f"Mapping more than one name to a class is currently not supported (class: {class_name})."
+ )
+ inverted_mappings[Reference.from_ref(v).class_name] = k
+ discriminator_mappings: Dict[str, Property] = {}
  for sub_prop_data in chain(data.anyOf, data.oneOf):
  sub_prop, schemas = property_from_data(
  name=name, required=required, data=sub_prop_data, schemas=schemas, parent_name=parent_name
  )
  if isinstance(sub_prop, PropertyError):
  return PropertyError(detail=f"Invalid property in union {name}", data=sub_prop_data), schemas
+
  sub_properties.append(sub_prop)
+ if data.discriminator is not None:
+ discriminated_by = inverted_mappings.get(sub_prop.reference.class_name)
+ if discriminated_by is not None:
+ discriminator_mappings[discriminated_by] = sub_prop
 
  default = convert_chain((prop._type_string for prop in sub_properties), data.default)
  return (
@@ -444,6 +462,8 @@ def build_union_property(
  default=default,
  inner_properties=sub_properties,
  nullable=data.nullable,
+ discriminator_property=data.discriminator.propertyName if data.discriminator else None,
+ discriminator_mappings=discriminator_mappings,
  description=data.description,
  ),
  schemas,