Annotated[schema(description=...)] erased when using Generic types

[Tom Cobb]

#280 went back to using get_type_hints, but appears to have lost the description annotations on Generic classes. Here's a snippet that works on 0.16.4:

from dataclasses import dataclass
from types import new_class
from typing import Any, Dict, Generic, TypeVar

from apischema import deserializer, schema, serializer
from apischema.conversions import Conversion
from apischema.graphql import graphql_schema
from apischema.tagged_unions import Tagged, TaggedUnion, get_tagged
from apischema.type_names import type_name
from graphql import print_schema
from typing_extensions import Annotated

Cls = TypeVar("Cls", bound=type)

T = TypeVar("T")

generic_name = type_name(lambda cls, *args: cls.__name__)

def as_tagged_union(cls: Cls) -> Cls:
    def serialization() -> Conversion:
        annotations = {sub.__name__: Tagged[sub] for sub in cls.__subclasses__()}
        namespace = {"__annotations__": annotations}
        tagged_union = new_class(
            cls.__name__,
            (TaggedUnion, Generic[T]),
            exec_body=lambda ns: ns.update(namespace),
        )
        return Conversion(
            lambda obj: tagged_union(**{obj.__class__.__name__: obj}),
            source=cls[T],
            target=tagged_union[T],
            # Conversion must not be inherited because it would lead to
            # infinite recursion otherwise
            inherited=False,
        )

    def deserialization() -> Conversion:
        generic_name(cls)
        for sub in cls.__subclasses__():
            generic_name(sub)

        namespace: Dict[str, Any] = {
            "__annotations__": {
                sub.__name__: Tagged[sub[T]] for sub in cls.__subclasses__()
            }
        }
        # Create the deserialization tagged union class
        tagged_union = new_class(
            cls.__name__,
            (TaggedUnion, Generic[T]),
            exec_body=lambda ns: ns.update(namespace),
        )
        return Conversion(
            lambda obj: get_tagged(obj)[1], source=tagged_union[T], target=cls[T]
        )

    deserializer(lazy=deserialization, target=cls)
    serializer(lazy=serialization, source=cls)
    return cls

@as_tagged_union
class Base(Generic[T]):
    bar: T

@dataclass
class Foo(Base[T]):
    bar: Annotated[T, schema(description="A Foo bar")]

@dataclass
class Bat(Base[T]):
    bar: Annotated[T, schema(description="A Foo bar")]

def get_bar(base: Base[str]) -> str:
    return base.bar

def test_fails():
    expected = '''\
type Query {
  getBar(base: BaseInput!): String!
}

input BaseInput {
  Foo: FooInput
  Bat: BatInput
}

input FooInput {
  """A Foo bar"""
  bar: String!
}

input BatInput {
  """A Foo bar"""
  bar: String!
}
'''
    assert print_schema(graphql_schema(query=[get_bar])) == expected

On 0.16.5 it fails with:

Traceback (most recent call last):
  File "/dls/science/users/tmc43/common/python/scanspec/tests/test_fails.py", line 103, in test_fails
    assert print_schema(graphql_schema(query=[get_bar])) == expected
AssertionError: assert ('type Query {\n'\n '  getBar(base: BaseInput!): String!\n'\n '}\n'\n '\n'\n 'input BaseInput {\n'\n '  Foo: FooInput\n'\n '  Bat: BatInput\n'\n '}\n'\n '\n'\n 'input FooInput {\n'\n '  bar: String!\n'\n '}\n'\n '\n'\n 'input BatInput {\n'\n '  bar: String!\n'\n '}\n') == ('type Query {\n'\n '  getBar(base: BaseInput!): String!\n'\n '}\n'\n '\n'\n 'input BaseInput {\n'\n '  Foo: FooInput\n'\n '  Bat: BatInput\n'\n '}\n'\n '\n'\n 'input FooInput {\n'\n '  """A Foo bar"""\n'\n '  bar: String!\n'\n '}\n'\n '\n'\n 'input BatInput {\n'\n '  """A Foo bar"""\n'\n '  bar: String!\n'\n '}\n')
    type Query {
      getBar(base: BaseInput!): String!
    }
    
    input BaseInput {
      Foo: FooInput
      Bat: BatInput
    }
    
    input FooInput {
  -   """A Foo bar"""
      bar: String!
    }
    
    input BatInput {
  -   """A Foo bar"""
      bar: String!
    }

[Joseph Perez]

Shame on me … I've forgotten one include_extras=True in #280.
I will fix it tonight and release a new patch (version 0.16.4 should be deleted because it's bugged).
Sorry for the inconvenience, I hope you can still work with v0.16.4 for now.

[Tom Cobb]

Thanks for the quick response, 0.16.4 will be fine for me, I only noticed because I have a weekly job on one of my projects that tests against the latest version of all its dependencies...

[Tom Cobb]

Thanks, all working now