Pylance says Cannot access member "schema" for type "Type[...]"

[davetapley]

I have this snippet in VSCode with Python 3.9.6 and Pylance (v2021.8.1105858891):

@dataclass_json
@dataclass
class Folder:
    Id: int
    Name: str

# mode code

        return Folder.schema().load(res.json()['Folders'], many=True)

And Pylance is underlining schema in red, saying:

Cannot access member "schema" for type "Type[Folder]"
  Member "schema" is unknownPylancereportGeneralTypeIssues

---

I'm opening here instead of against Pylance to see if others are seeing this, and just in case something it's something with ⬇️ which is confusing/breaking Pylance 🤔

dataclasses-json/dataclasses_json/api.py

Line 89 in 3dc59e0

def schema(cls: Type[A],

[bentheadset]

It appears to me that pylance is struggling with certain uses methods on @dataclass classes.

For instance, in some circumstances:

from my_module import MyBaseClass

@dataclass
class` Foo(MyBaseClass):
    a: int
    def foo(self):
        print("...")

def bar() -> Foo:
    return Foo(a=0)

bar().foo()   # <-- pylance error

pylance will flag foo() call, "Cannot access member "foo" for type "Dataclass"

I haven't had time to verify if this is related to

• the type hints (error mentions Dataclass NOT the udt),
• or the MRO or other inheritence issue (if I remove the inheritance from MyBaseClass, pylance accepts the code)
  • note, perhaps NOT similar to @davetapley 's reproduction, as @dataclass_json is not altering MRO but rather just adds cls attrs

[lidatong]

this is probably a general problem of visibility of the class decorator to static type checkers -- i've begun looking into various solutions for this

[george-zubrienko]

Should be fixed as a result of #442 work - with a breaking change most likely