Pyright cannot recognize the type of `SQLModel.__tablename__`

[Ma233]

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the SQLModel documentation, with the integrated search.
• I already searched in Google "How to X in SQLModel" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to SQLModel but to Pydantic.
• I already checked if it is not related to SQLModel but to SQLAlchemy.

Commit to Help

• I commit to help with one of those options 👆

Example Code

from sqlmodel import SQLModel

reveal_type(SQLModel.__tablename__)

# mypy(0.910) output: Revealed type is "Union[builtins.str, def (*Any, **Any) -> builtins.str]"
# pyright(1.1.166) output: Type of "SQLModel.__tablename__" is "declared_attr"


class User(SQLModel, table=True): # pyright error: Instance variable "__name__" overrides class variable of same name in class "SQLModel"
 __tablename__ = "users" # pyright error: Expression of type "Literal['users']" cannot be assigned to declared type "declared_attr"
 name: str

Description

This will cause a type error when you declare __tablename__ with pyright as type checker. Like:

Expression of type "Literal['users']" cannot be assigned to declared type "declared_attr"

Operating System

Linux, macOS

Operating System Details

No response

SQLModel Version

0.0.4

Python Version

3.8.6

Additional Context

No response

[Chedi]

this is my workaround to silence that type of errors (not my proudest hack but it work)

from sqlmodel import SQLModel
from sqlalchemy.orm import declared_attr

class User(SQLModel, table=True): 
 name: str

 @declared_attr
 def __tablename__(cls): # noqa: N805
 return 'users'

inspired by the declared_attr documentation, tested with pyright 1.1.172 (Linux), python 3.9.7, sqlmodel 0.0.4

[Ma233]

@Chedi Hi, of my own workaround is adding a # type: ignore after __tablename__ = "users".

[mudassirkhan19]

With @Chedi 's workaround, I still get an error on Mypy: error: Signature of "__tablename__" incompatible with supertype "SQLModel".
Only # type: ignore works.

[indivisible]

another really easy workaround is just specifying the type: __tablename__: str = 'poop'

[cassieopea]

another really easy workaround is just specifying the type: __tablename__: str = 'poop'

Note that Pyright complains at this:

"__tablename__" incorrectly overrides property of same name in class "SQLModel" Pylance(reportIncompatibleMethodOverride)

To satisfy the type checker you need to use the declared_attr approach, eg:

class Lineitem(SQLModel, table=True):
 @declared_attr
 def __tablename__(cls):
 return "invoice_lineitems"

This could be mentioned in the docs, and maybe in a future version a more intuitive approach could be used, such as putting it in a Meta as ormar does:

class Lineitem(SQLModel, table=True):
 class Meta:
 tablename: str = "invoice_lineitems"

I thought about making a request for this but I'm guessing there's already a lot on the roadmap.

[cassieopea]

Since I posted #98 (comment), I've started simply doing

 __tablename__: str = "invoices_legacy" # type: ignore

I think this is by far the best solution for people still getting the "incorrect override" error for the line without type: ignore. As I said when I mentioned this in #159,

I choose this last method because the others are far too verbose for something as simple as declaring the table name. This may seem hacky, but although I have to tell Pyright to ignore a number of things in sqlmodel, it's not half the file like I have to type: ignore with sqlalchemy.

[anton-fomin]

It seems

 __tablename__: ClassVar[str] = "users"

Solves this for both pyright and mypy

Updated
Works only with basic type checking mode. Does not work in standard

[chriscarrollsmith]

I tried all the fixes in this thread, and I'm sorry to report that you'll need # type: ignore to fix this with Pylance in "standard" type checking mode, because none of the other suggestions work.

[madduck]

I use

__tablename__ = typing.cast(declared_attr, "Users")

and be done with it.

[youhogeon-meritz]

It works on pyright strict mode . But not graceful.

__tablename__: ClassVar[Any] = "my_table"

[madduck]

__tablename__: ClassVar[Any] = "my_table"

I can confirm this works for pyright and mypy.

[marcoshevaristo]

Since I posted #98 (comment), I've started simply doing

__tablename__: str = "invoices_legacy" # type: ignore

I think this is by far the best solution for people still getting the "incorrect override" error for the line without type: ignore. As I said when I mentioned this in #159,

I choose this last method because the others are far too verbose for something as simple as declaring the table name. This may seem hacky, but although I have to tell Pyright to ignore a number of things in sqlmodel, it's not half the file like I have to type: ignore with sqlalchemy.

I can confirm this works.