Possible regression of __modify_schema__ for enum fields

[therefromhere]

Bug

A side-effect of #1432 is that __modify_schema__ on enum subclasses is still affecting the field schema, rather than the enumeration schema.

I'd like it if __modify_schema__ applied to the resulting enum model. Does that seem reasonable?

In my use case I'm subclassing enum to add a tsEnumNames property, so that I could generate proper typescript enums from the resulting Json schema (using json-schema-to-typescript - see bcherny/json-schema-to-typescript#15 ).

Using latest master 2eb62a3 (or d560c57 from #1562)

import enum
import pydantic


class TsCompatibleEnum(enum.Enum):
  """Enum subclass that adds tsEnumNames to enumeration fields
  for compatibility with json-schema-to-typescript

  See https://github.com/bcherny/json-schema-to-typescript/pull/15
  """
  @classmethod
  def __modify_schema__(cls, field_schema):
    field_schema["tsEnumNames"] = list(e.name for e in cls)


class MyEnum(TsCompatibleEnum):
  """Enumeration - note that the names and values are different"""
  FOO = "foo"
  BAR = "bar"


class MyModel(pydantic.BaseModel):
  my_field: MyEnum = MyEnum.FOO


print(MyModel.schema_json(indent=2))

Outputs:

{
  "title": "MyModel",
  "type": "object",
  "properties": {
    "my_field": {
      "$ref": "#/definitions/MyEnum",
      "tsEnumNames": [
        "FOO",
        "BAR"
      ]
    }
  },
  "definitions": {
    "MyEnum": {
      "title": "MyEnum",
      "description": "Enumeration - note that the names and values are different",
      "enum": [
        "foo",
        "bar"
      ]
    }
  }
}

vs with pydantic 1.5.1:

{
  "title": "MyModel",
  "type": "object",
  "properties": {
    "my_field": {
      "title": "My Field",
      "default": "foo",
      "enum": [
        "foo",
        "bar"
      ],
      "tsEnumNames": [
        "FOO",
        "BAR"
      ]
    }
  }
}

I'd like to get this instead:

{
  "title": "MyModel",
  "type": "object",
  "properties": {
    "my_field": {
      "$ref": "#/definitions/MyEnum"
    }
  },
  "definitions": {
    "MyEnum": {
      "title": "MyEnum",
      "description": "Enumeration - note that the names and values are different",
      "enum": [
        "foo",
        "bar"
      ],
      "tsEnumNames": [
        "FOO",
        "BAR"
      ]
    }
  }
}

[samuelcolvin]

I'm confused, is this the same or linked to #1552?

[therefromhere]

No, I think it's unrelated.