I've been trying to define a cached pipeline parameterized by a pydantic object as the only input to my function. I noticed however that joblib.hash() result depends on whether or not you pass the value for the default-valued attribute at construction (even if your passed value is same as default). See MRE:

import pydantic
import joblib

class Config(pydantic.BaseModel):
    field1: int
    field2: int = 5

c1 = Config(field1=0)
c2 = Config(**c1.dict())
c3 = Config(**c1.dict())

print(f"{(c1 == c2)=}")
print(f"{(c2 == c3)=}")
print(f"{(joblib.hash(c1) == joblib.hash(c2))=}")
print(f"{(joblib.hash(c2) == joblib.hash(c3))=}")
print(f"{joblib.__version__=}")
print(f"{pydantic.__version__=}")

Output:

(c1 == c2)=True
(c2 == c3)=True
(joblib.hash(c1) == joblib.hash(c2))=False
(joblib.hash(c2) == joblib.hash(c3))=True
joblib.__version__='1.3.2'
pydantic.__version__='1.10.13'

Expected True in all comparisons.
If I remove the default field (field2: int = 5) everything works as expected.