Raise an error when using field(init=False)

[dfurtado]

Description

The issue occurs when defining a field in the dataclass with the property init=False. When it init property is set to false it means that the auto-generated dataclass initializer won't add the field in the list of arguments.

How to reproduce

1. Create a dataclass and set init=False in one of the fields, for example:

from dataclasses import dataclass, field

from dataclass_csv import DataclassReader


@dataclass
class User:
    firstname: str
    lastname: str
    age: int = field(init=False)

2. Try reading a csv file containing the expected data

def main():

    with open('users.csv') as f:
        reader = DataclassReader(f, User)

        for row in reader:
            print(row)


if __name__ == '__main__':
    main()

3. You will see the error on the terminal:

Traceback (most recent call last):
  File "app.py", line 25, in <module>
    main()
  File "app.py", line 20, in main
    for row in reader:
  File "/home/daniel/Envs/test-oGAe6Cfg/lib/python3.7/site-packages/dataclass_csv/dataclass_reader.py", line 161, in __next__
    return self._process_row(row)
  File "/home/daniel/Envs/test-oGAe6Cfg/lib/python3.7/site-packages/dataclass_csv/dataclass_reader.py", line 157, in _process_row
    return self.cls(*values)
TypeError: __init__() takes 3 positional arguments but 4 were given

Expected behavior

When setting init=False in a dataclass field, the field should not be passed to the dataclass initializer.

Other information

OS: Debian 4.9.130-2
Python version: 3.7.1
dataclass-csv version: 1.0.1

[schobster]

Hi @dfurtado - feel free to assign this one (and/or #10) to me if you would like some assistance 😸

[dfurtado]

Hi @schobster , thanks a lot, I actually started on this one, I forgot to assign it to me. I will assign the #10 to you.

[rtdean]

Just hit this one, but in a slightly different way. I have a field that's marked as init=False, and doesn't have a corresponding field to map into it, and dataclass_csv doesn't like that much:

KeyError: 'The value xyzzy is missing in the CSV file.'

[rtdean]

It looks like the fix in #15 should fix my side of the issue as well.

[dfurtado]

Solved #15