ERR: read_csv exposes an internal function when bad argument is specified

[dsaxton]

When a user tries to specify a non-existent argument in read_csv the error message pertains to what seems to be an internal function (parser_f). This behavior might be a bit surprising / confusing to users, who would expect the error message to refer to the function actually being used.

import pandas as pd
df = pd.read_csv("some_file.csv", bad_arg=True)

yields

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-2-d4606a60902f> in <module>()
----> 1 df = pd.read_csv("some_file.csv", bad_arg=True)

TypeError: parser_f() got an unexpected keyword argument 'bad_arg'

[WillAyd]

These IO functions are built dynamically:

pandas/pandas/io/parsers.py

Line 704 in f886139

parser_f.__name__ = name

Personally not sure how the traceback is built but certainly welcome to take a look. Maybe should be using functools.wraps here?

[chris-b1]

Not sure there is an easy way to do this - that error message seems to be using the code object name, which can't be modified

In [24]: def orig_func(a):
    ...:     return a
 
In [25]: new_func = orig_func
         new_func.__name__ = 'new_func'
         new_func.__qualname__ = 'new_func'

In [26]: new_func(b=2)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-26-4e081338f0ff> in <module>()
----> 1 new_func(b=2)

TypeError: orig_func() got an unexpected keyword argument 'b'

In [27]: new_func.__code__.co_name
Out[27]: 'orig_func'

In [28]: new_func.__code__.co_name = 'new_func'
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-28-89626da5926c> in <module>()
----> 1 new_func.__code__.co_name = 'new_func'

AttributeError: readonly attribute

[chris-b1]

SO here - https://stackoverflow.com/questions/40661758/name-of-a-python-function-in-a-stack-trace

[simonjayhawkins]

This needs further discussion, see #33023