Cannot set `min_length` for optional string filed

[RoTorEx]

Description

Error while creating an object with optional filed with min_length meta.

from typing import Annotated

import msgspec


class Author(msgspec.Struct):
    name: Annotated[str, msgspec.Meta(min_length=1)]
    biography: Annotated[None | str, msgspec.Meta(min_length=10)]


element = {"name": "Me", "biography": None}

author = msgspec.convert(element, type=Author)

---

Traceback (most recent call last):
File "", line 198, in _run_module_as_main
File "", line 88, in _run_code
File "/path/report.py", line 13, in
author = msgspec.convert(element, type=Author)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: Can only set min_length on a str, bytes, or collection type - type typing.Annotated[None | str, msgspec.Meta(min_length=10)] is invalid

---

msgspec version 0.19.0

[oek1ng]

None does not have a length, is that an issue? Try to use Annonated[str, msgspec.Meta(min_length=10)] | None