Provide a way to disable `datetime` being converted to `str`

[uyha]

Currently, https://github.com/yukinarit/pyserde/blob/35901de31a8b135c777710d5388c8f5a0f11dc66/serde/se.py#L383-L384 converts datetime to an ISO string unconditionally. This makes the msgpack serializer unable to convert datetime to its extension type in the spec. It would be nice to have a flag to disable this convertion and let the serializer handle it.

[yukinarit]

Hi @uyha Can you please try reuse_instances=True?

This is how objects are treated within generated code.

[uyha]

I changed https://github.com/yukinarit/pyserde/blob/a517254b18b2927348b94f59de095ce873abe101/serde/msgpack.py#L71 to

 kwargs: Any = {"c": cls, "reuse_instances": True, "convert_sets": True} 

with the following snippet, it still converts the datetime object to a str

from serde.msgpack import to_msgpack

from datetime import datetime

from msgpack import packb

time = datetime.fromisoformat("2020-01-01 00:00:00+00")
print(to_msgpack(time, datetime=True))
print(packb(time, datetime=True))

which outputs

b'\xb92020-01-01T00:00:00+00:00'
b'\xd6\xff^\x0b\xe1\x00'

[yukinarit]

Ah,

1. reuse_instances are not available in to_msgpack
2. reuse_instances works only for dataclass field

   
   @dataclass
   class Foo:
   v: datetime

f = Foo(datetime.fromisoformat("2020-01-01 00:00:00+00")) print(to_dict(f, reuse_instances=True)) print(to_dict(f, reuse_instances=False))

it prints

{'v': datetime.datetime(2020, 1, 1, 0, 0, tzinfo=datetime.timezone.utc)} {'v': '2020-01-01T00:00:00+00:00'}

[yukinarit]

ok, I found a way to fix. let me post it tomorrow

[yukinarit]

@uyha v0.14.2 was published to PyPI. Please take a look if it resolves your issue.

[uyha]

yup, works