Pyright's Type Inference for DataFrame.reset_index(inplace=False)

[nghiant03]

portfolio_values = portfolio_values[portfolio_values['date'].dt.weekday < 5].reset_index(drop=True, inplace=False)
 └╴E Type "DataFrame | None" is not assignable to declared type "DataFrame"
       Type "DataFrame | None" is not assignable to type "DataFrame"
         "None" is not assignable to "DataFrame" Pyright (reportAssignmentType) [39, 24]

The docs explicitly states that it only returns None when inplace=True

[Dr-Irv]

Can you provide more detail? I would need to know the pyright version, command line vs. VS Code, etc.

With this example,

def foobar(portfolio_values: pd.DataFrame):

    reveal_type(
        portfolio_values[portfolio_values['date'].dt.weekday < 5]
        .reset_index(drop=True, inplace=False))

I get

\issue1145.py:5:9 - information: Type of "portfolio_values[portfolio_values['date'].dt.weekday < 5].reset_index(drop=True, inplace=False)" is "DataFrame"

[nghiant03]

I install pandas-stubs via conda:

❯ conda list pandas
# packages in environment at /home/Sinner/miniforge3:
#
# Name                    Version                   Build  Channel
pandas                    2.2.3           py312hf9745cd_1    conda-forge
pandas-stubs              2.2.3.241126       pyhd8ed1ab_1    conda-forge
❯ pyright --version
pyright 1.1.395

I just run this example:

from typing import reveal_type
import pandas as pd

def foobar(porfolio_values: pd.DataFrame):
    reveal_type(porfolio_values[porfolio_values['date'].dt.weekday < 5].reset_index(drop=True, inplace=False))

    porfolio_values = porfolio_values[porfolio_values['date'].dt.weekday < 5].reset_index(drop=True, inplace=False)
    return porfolio_values

❯ pyright main.py
/home/Sinner/Github/Playground/main.py
  /home/Sinner/Github/Playground/main.py:5:17 - information: Type of "porfolio_values[porfolio_values['date'].dt.weekday < 5].reset_index(drop=True, inpla
ce=False)" is "DataFrame | None"
  /home/Sinner/Github/Playground/main.py:7:23 - error: Type "DataFrame | None" is not assignable to declared type "DataFrame"
    Type "DataFrame | None" is not assignable to type "DataFrame"
      "None" is not assignable to "DataFrame" (reportAssignmentType)
1 error, 0 warnings, 1 information 

[Dr-Irv]

pyright 1.1.395 broke a lot of stuff with pandas-stubs, so can you upgrade to pyright 1.1.396 which fixed that?