Open issue: introspection: module name, sane defaults

[Viicos]

The introspection is meant to be provide high-level utilities to inspect annotations at runtime.

• The current module name could be changed. Any ideas?

• There are two functions — get_literal_values() and inspect_annotation() — that can unpack PEP 695 type aliases. When such type aliases are encountered, you generally don't need to unpack them eagerly. For instance, with the following:

  type MyInt = Annotated[int, Gt(1)]
  
  @my_dataclass
  class MyClass:
      m: list[MyInt]

  You can retrieve the value of the MyInt alias only when processing the class argument of list.
  However, there are cases where having type aliases eagerly unpacked is beneficial. For instance:

  type MyInt = Annotated[int, field(alias='test')]
  
  @my_dataclass
  class MyClass:
      m: Myint

  The @my_dataclass implementation could benefit from having MyInt eagerly unpacked, so that it can detect the field alias early in the class creation (in Pydantic, this happens in the first class creation step, fields collection. We then have a step to generate the type validation logic, and realizing that the annotated metadata contains field metadata such as aliases isn't ideal).

  For this reason, the default value for unpack_type_aliases is to unpack them eagerly. However, this makes the functions unsafe as NameErrors can happen. Probably we should switch to skip as a default value, but recommend using eager.

[Viicos]

• The @my_dataclass implementation could benefit from having MyInt eagerly unpacked, so that it can detect the field alias early in the class creation (in Pydantic, this happens in the first class creation step, fields collection. We then have a step to generate the type validation logic, and realizing that the annotated metadata contains field metadata such as aliases isn't ideal).

Turns out we changed this recently. A better default for inspect_annotation() would be to skip unpacking type aliases. The current get_literal_values() default will be kept however.