Wrapping a check_input causes index out of range

[mastersplinter]

The following example:

from pandera import DataFrameSchema, Int, DateTime, String, Check, Column, Float, Bool, check_output, check_input
import pandas as pd
import numpy as np
from gsktools import load_data

df = pd.DataFrame({
        "column1": [10.0, 20.0, 30.0],
        "column2": [1, 2, 3],
    })
​
schema = DataFrameSchema({
        "column1": Column(Float),
        "column2": Column(Int),
    })

@check_input(schema,1)
def original_function(some_arg, df):
    return df

def wrapper(function_as_parameter,positional_arguments):
    df = function_as_parameter(positional_arguments)
    return df

def function_that_calls_original_function_via_wrapper(df):
    new_df = wrapper(
            function_as_parameter=original_function,
            positional_arguments=df)

function_that_calls_original_function_via_wrapper(df)

Results in this list index out of range error:

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-100-da3315e2c30b> in <module>
----> 1 function_that_calls_original_function_via_wrapper(df)

<ipython-input-99-0075cf7550ed> in function_that_calls_original_function_via_wrapper(df)
      2     new_df = wrapper(
      3             function_as_parameter=original_function,
----> 4             positional_arguments=df)

<ipython-input-98-c6fbf50f8087> in wrapper(function_as_parameter, positional_arguments)
      1 def wrapper(function_as_parameter,positional_arguments):
----> 2     df = function_as_parameter(positional_arguments)
      3     return df

/pandera_dev/pandera/pandera.py in _wrapper(fn, instance, args, kwargs)
    766                     zip(arg_spec_args, args))
    767                 args_dict[obj_getter] = schema.validate(args_dict[obj_getter])
--> 768                 args = list(args_dict.values())
    769         elif obj_getter is None:
    770             try:

IndexError: list index out of range

[cosmicBboy]

the check_input call should be @check_input(schema), or @check_input(schema, 0) since the second argument is 0-indexed (if obj_getter is an integer)

[cosmicBboy]

not sure if this is important, but positional args should also be a list/tuple and unpacked on function call

def wrapper(function_as_parameter, positional_arguments):
    df = function_as_parameter(*positional_arguments)
    return df

def function_that_calls_original_function_via_wrapper(df):
    new_df = wrapper(
            function_as_parameter=original_function,
            positional_arguments=(df, ))

[mastersplinter]

I need to investigate more, after playing with my toy example it's now fixed. I need to investigate my original code (which is much more complicated) and figure out if this is actually a pandera issue or not. Closing for now.