[Python] How to make Pydantic's non-strict, coercive mode apply to integer literals?

I'm validating inputs to a function using Pydantic's @validate_call as follows:

from typing import Literal
from pydantic import validate_call

@validate_call
def foo(a: Literal[0, 90, 180, 270]) -> None:
print(a, type(a))


I want Pydantic to perform its default type coercion like it does with the int type:

foo(90) # Works as expected
foo('90') # Doesn't work, but I want it to


If I use the annotation a: int, it will coerce strings like '180', but then I have to manually validate which integers are given.

How do I make Pydantic perform type coercion on Literals?

Note: I'll accept a solution that requires a to be a string type instead of an integer, as long as it still allows both integer and string input.

Bad Solutions

• 
  I don't want to add every literal case. Literal[0, 90, 180, 270, '0', '90', '180', '270'] is bad because it doesn't allow the strings '-0' or '180.0'.
  
  
• 
  I could do Annotated[int, Field(ge=0, le=0)] | Annotated[int, Field(ge=90, le=90)] | ..., but that's stupidly verbose.
  
  
• 
  I don't want to define some separate function or model. At that point, it's easier to just accept a: int and validate the particular value inside the method.
  

Continue reading...