.dict(skip_defaults=True) skips fields populated by alias

[sommd]

Bug

For bugs/questions:

• OS: Linux

• Python version import sys; print(sys.version): 3.7.3 (default, Mar 26 2019, 21:43:19) [GCC 8.2.1 20181127]

• Pydantic version import pydantic; print(pydantic.VERSION): 0.25

When using .dict(skip_defaults=True) with an aliased field, if that field was populated by the alias (i.e. Foo(alias_name=...) instead of Foo(field_name=...)) then it is always skipped. Happens with by_alias set to True and False as well.

from pydantic import BaseModel, Schema


class Foo(BaseModel):
    class Config:
        allow_population_by_alias = True
    
    a: int = Schema(1, alias="b")


# Correct
print(Foo())  # Foo a=1
print(Foo().dict(by_alias=False, skip_defaults=False))  # {'a': 1}
print(Foo().dict(by_alias=True, skip_defaults=False))  # {'b': 1}
print(Foo().dict(by_alias=False, skip_defaults=True))  # {}
print(Foo().dict(by_alias=True, skip_defaults=True))  # {}

# Correct
print(Foo(a=2))  # Foo a=2
print(Foo(a=2).dict(by_alias=False, skip_defaults=False))  # {'a': 2}
print(Foo(a=2).dict(by_alias=True, skip_defaults=False))  # {'b': 2}
print(Foo(a=2).dict(by_alias=False, skip_defaults=True))  # {'a': 2}
print(Foo(a=2).dict(by_alias=True, skip_defaults=True))  # {'b': 2}

# Correct
print(Foo(b=2))  # Foo a=2
print(Foo(b=2).dict(by_alias=False, skip_defaults=False))  # {'a': 2}
print(Foo(b=2).dict(by_alias=True, skip_defaults=False))  # {'b': 2}
# Incorrect
print(Foo(b=2).dict(by_alias=False, skip_defaults=True))  # {}
print(Foo(b=2).dict(by_alias=True, skip_defaults=True))  # {}

[sommd]

After looking into it a bit, it looks like .dict() get's the values of the set fields from __fields_set__. __fields_set__ doesn't contain the name of the field if it was set by the alias. E.g:

print(Foo().__values__)  # {'a': 1}
print(Foo().__fields_set__)  # set()
print(Foo(a=2).__values__)  # {'a': 2}
print(Foo(a=2).__fields_set__)  # {'a'}
print(Foo(b=2).__values__)  # {'a': 2}
print(Foo(b=2).__fields_set__)  # set()

Is the behaviour for __fields_set__ wrong or should .dict() be using something else to get the fields?

[haizaar]

Just hit this one as well.

[haizaar]

THANK YOU!

…

On Sat, 18 May 2019 at 21:11, Samuel Colvin ***@***.***> wrote: Closed #517 <#517> via #518 <#518>. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#517>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAOGWJ67MLJ4HH6PRIX4HDPV7P6PANCNFSM4HMJNMOQ> .

-- Zaar