SNOW-1952961: Type Errors on DataFrame Functions Due to Missing Optional Type Hints

[zaramzamzam]

Please answer these questions before submitting your issue. Thanks!

1. What version of Python are you using?
   Python 3.11.7

2. What operating system and processor architecture are you using?

macOS-15.3.1-arm64-arm-64bit

3. What are the component versions in the environment (pip freeze)?

snowflake-connector-python==3.13.2
snowflake-snowpark-python==1.28.0

4. What did you do?

Accessing functions on a snowpark dataframe results in errors due to mishandling of types in the snowpark library.

Example:
Using type checkers (Pylance/Pyright in VS Code)
Results in error:

Argument of type "None" cannot be assigned to parameter "_ast_stmt" of type "Assign" in function "filter"
  "None" is not assignable to "Assign"Pylance[reportArgumentType](https://github.com/microsoft/pyright/blob/main/docs/configuration.md#reportArgumentType)

Example code:

from snowflake import snowpark
from snowflake.snowpark.functions import col

def example(session: snowpark.Session):
    session.table("example_table").where(col("col1") == "value1")

5. What did you expect to see?

This should not result in a type error.

More information:

This seems to be introduced in snowflake-snowpark-python versions > 1.25.0 due to assigning None to arguments which are not marked as optional.

Example line

[jjlkant]

I also just ran into the same issue, on e.g. session.sql() and DataFrame.with_column() calls.

A temporary workaround seems to be that pyright <= 1.1.394 is able to work with this Optional[...] missing, but the latest version rightfully throws errors.

[sfc-gh-sghosh]

Hello @zaramzamzam ,

Thanks for raising the issue, we are looking into it, will update.

Regards,
Sujan