stubs: add pandas.io.sql.get_schema to fix Pylance reportAttributeAcc…

[SadeghPouriyanZadeh]

Summary

Add a stub for pandas.io.sql.get_schema. The function exists at runtime but
is missing from the pandas-stubs, causing Pylance/Pyright to report:

"get_schema" is unknown import symbol (reportAttributeAccessIssue)

Rationale

• Improves developer experience in VS Code / Pyright without changing pandas runtime.
• Keeps pandas’ API policy unchanged (no need to modify pandas or __all__).

Signature

def get_schema(
    frame: DataFrame,
    name: str,
    keys: str | Sequence[str] | None = ...,
    con: Any = ...,
    dtype: DtypeArg | None = ...,
    schema: str | None = ...,
) -> str: ...

[cmp0xff]

This function is mentioned nowhere else in the docs except for What's new's. If it is indeed internal, we will not include it in the stubs. @Dr-Irv could you confirm?

[SadeghPouriyanZadeh]

I'm using it via pandas.io.sql. Does it help?

[cmp0xff]

Thank you for following up. I understand that you use pandas.io.sql.get_schema and that adding it to stubs could be helpful.

I would like to refer to README.md, where it states

The https://github.com/pandas-dev/pandas-stubs/ project provides type declarations for the pandas public API.

[SadeghPouriyanZadeh]

Thanks. I haven't read that part. I get it now. I thought internal APIs are included too.

[Dr-Irv]

This function is mentioned nowhere else in the docs except for What's new's. If it is indeed internal, we will not include it in the stubs. @Dr-Irv could you confirm?

Yes, I confirm.

Having said that, there is a 10-year old issue in pandas discussing whether this should be documented. See pandas-dev/pandas#9960

Once that is resolved, we could add it in pandas-stubs

[SadeghPouriyanZadeh]

@Dr-Irv thanks for your comment. I didn't know the history of get_schema. I commented there and I happily hope they decide sooner. Because this feature is fundamental to AI RAG use cases. Thanks again 🙏

[cmp0xff]

I'll close the MR for now. Please ping us here if the function gets published.