Cannot create type codec for composite type with certain field types.

Hello, I noticed I can't create a type codec for a composite type if it has a field of type json, a jsonb or a geometry type. Why is so and is there a way to sidestep this issue?

import json
from dataclasses import dataclass

@dataclass
class Foo:
    data: dict

await conn.execute("CREATE TABLE foo (data jsonb NOT NULL);")

await conn.set_type_codec(
    "foo", 
    schema="public",
    encoder=lambda foo: (json.dumps(foo.data),), 
    decoder=lambda row: Foo(json.loads(row)), 
    format="tuple",
)

UnsupportedClientFeatureError: cannot decode type "public"."foo": text encoding of composite types is not supported

首先通过 conn.set_type_codec 使用包含 jsonb 字段的复合类型重现该示例，然后检查复合 codec 的处理方式以及 PostgreSQL 类型格式的约束。完成的标准是确定支持所报告的字段类型，或清楚地记录该限制和一种受支持的变通方案。