mypy: invalid type comment or annotation

Hi,

I think this issue related more to mypy, but maybe you know about any workaround or how to solve this.

Here is my code:

class Test(BaseModel):
    k: constr(min_length=2)

And when I run mypy I got:

error: invalid type comment or annotation
note: Suggestion: use constr[...] instead of constr(...)

Any ideas?

[mattzque]

This should be mentioned in the documentation:

https://pydantic-docs.helpmanual.io/usage/types/#constrained-types

is incompatible with mypy at the moment

[m-laniakea]

The above is not quite right as well, because the first parameter to Field is the default value. In this case the default would be the type str, which is not a str.

Another possible issue is that a default value was supplied, making this field optional.

Updated example:

class User(BaseModel):
    name: str = Field('Default name', max_length=255, strip_whitespace=True)

If you want to make the field a Required field, use an ellipsis:

class User(BaseModel):
    name: str = Field(..., max_length=255, strip_whitespace=True)

Something like required=True would feel more natural, but that’s not an option as of v1.4. Please be aware that supplying a default of None is not the same as supplying no default value.