MyPy blows up on the exotic types that return types, e.g. conint

from pydantic import BaseModel, conint

class MyPyProblem(BaseModel):
    big_int: conint(gt=1000, lt=1024) = None

mypy --verbose tests/test_pydantic_bug_report.py

LOG:  Mypy version 0.620
LOG:  Could not load cache for tests.test_pydantic_bug_report: .mypy_cache/3.6/tests/test_pydantic_bug_report.meta.json
LOG:  Metadata not found for tests.test_pydantic_bug_report
LOG:  Parsing tests/test_pydantic_bug_report.py (tests.test_pydantic_bug_report)
LOG:  Bailing due to parse errors
LOG:  Build finished in 0.001 seconds with 0 modules, and 2 errors
tests/test_pydantic_bug_report.py:4: error: invalid type comment or annotation
tests/test_pydantic_bug_report.py:4: note: Suggestion: use conint[...] instead of conint(...)

I tried both the recommendation of [] and aliasing it (e.g. BIG_INT=conint(gt=1000, lt=1024))

[samuelcolvin]

This is the kind of thing I find very frustrating about mypy. There’s no more detail than Invalid type, what am I supposed to do with that?

This works:

from typing import cast
from pydantic import BaseModel, ConstrainedInt

class BigInt(ConstrainedInt):
    gt = 1000
    lt = 1024

class MyModel(BaseModel):
    foo: BigInt  # required
    bar: BigInt = cast(BigInt, 1001)  # with a default

m = MyModel(foo=1011)
print(m.dict())

You have to use cast(BigInt, 1001) to avoid mypy whinging that 1001 is not an instance of BigInt.

[paulloubetpreligens]

Something like this works for me : big_int: conint(gt=1000, lt=1024) = None # type: ignore