False positive: Field has no items() member

[kazaamjt]

Steps to reproduce

from typing import Dict
from dataclasses import dataclass, field

@dataclass
class TestClass:
	foo: str
	bar: str
	baz_dict: Dict[str, str] = field(default_factory=dict)

	def some_func(self) -> None:
		for key, value in self.baz_dict.items():
			print(key)
			print(value)

Current behavior

Pylint reports:
"Instance of 'Field' has no 'items' member"

Expected behavior

No error, because the field is a Dict and thus does have the items() member.
(Pylint thinks it's just a Field, but it's the default factory returns a dict)

pylint --version output

pylint 2.1.1
astroid 2.0.4
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)]

(I also tested with "pip install pylint astroid --pre -U", which resulted in the same thing)

[PCManticore]

Thanks for creating an issue @kazaamjt Pylint currently does not fully understand dataclasses, we'll probably need inference support in inferring field as the type of the value passed via default_factory

[jfthuong]

Note: of course same behavior with keys and values :)

[eduardomezencio]

While dataclasses are not supported, is there a way to disable certain checks on dataclasses only, using pylintrc?

[PCManticore]

You can try --ignored-classes to see if it helps.

[yellowhat]

Hi,
may I ask to reopen this issue.
I have the following code:

@dataclass
class Case:
    """Case class (group Item)"""

    name: str
    irr: float = 0
    items: List[Item] = field(default_factory=lambda: [])

    def add_item(self, item: Item) -> None:
        """Add an item to the item list."""

        self.items.append(item)

With the version 2.10.2, pylint returns:

E1101: Instance of 'Field' has no 'append' member (no-member)

Thanks

[Pierre-Sassoulas]

Hi @yellowhat, could you open a new issue, please ?