SQLModel cannot fetch the type of a enum field containing Annotated type

[fubuloubu]

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Example Code

def iso_format(dt: datetime) -> str:
    return dt.isoformat()

ISOTimestamp = Annotated[
    datetime,
    PlainSerializer(iso_format, return_type=str),
]

class Product(BaseModel, table=True):
    created: ISOTimestamp = Field(default_factory=utc_now, nullable=False)
    deprecated: ISOTimestamp | None = Field(default=None)  # Works if I remove this field

Description

When loading the above model I get

  ...
  File "site-packages/sqlmodel/main.py", line 474, in __new__
    col = get_column_from_field(v)
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "site-packages/sqlmodel/main.py", line 618, in get_column_from_field
    sa_type = get_sqlalchemy_type(field)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "site-packages/sqlmodel/main.py", line 567, in get_sqlalchemy_type
    if issubclass(type_, Enum):
       ^^^^^^^^^^^^^^^^^^^^^^^
TypeError: issubclass() arg 1 must be a class

Operating System

Linux

Operating System Details

No response

SQLModel Version

0.0.16

Python Version

3.11.7

Additional Context

No response

[joachimhuet]

In fact this error comes from sqlalchemy, you can see that the error disapeear if you remove the tablle=True

So what you can do is specify a sa_type to make sqlalchemy understand what type you actually want to be used in the database side.

Something like that should fix your problem:

from sqlalchemy import DateTime  # if you want the DateTime type or String if you want it to be a string

class Product(BaseModel, table=True):
    created: ISOTimestamp = Field(default_factory=utc_now, nullable=False, sa_type=DateTime)
    deprecated: ISOTimestamp | None = Field(default=None, sa_type=DateTime)

[fubuloubu]

Ah okay, this makes sense as it skips the requirement to dynamically infer the SA type (just need to add nullable too)