`_env_file` keyword has no effect

[bthorsted]

As the title says, _env_file is ignored at runtime.

MWE

from pydantic_settings import BaseSettings, SettingsConfigDict

class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        env_nested_delimiter="__",
        env_file=(".env", ".env.prod"),
        extra="ignore",
    )

settings = Settings(_env_file=".env.test")
print(f"{settings.model_config.get('env_file') = }")

Expected behavior

settings.model_config.get('env_file') = '.env.test'

Actual behavior

settings.model_config.get('env_file') = ('.env', '.env.prod')

System info

OS: Windows 11 Enterprise, version 23H2
Python version: 3.12.9
pydantic-settings 2.10.1
pydantic 2.11.7
pydantic-core 2.33.2

[hramezani]

As the title says, _env_file is ignored at runtime.

@bthorsted, I think this is the right behaviour because you are getting the value from model_config and the ('.env', '.env.prod') are already assigned to env_file of model_config

[bthorsted]

@hramezani, no it is not the right behavior. According to the documentation (source: Settings Management - Pydantic):

Passing a file path via the _env_file keyword argument on instantiation (method 2) will override the value (if any) set on the model_config class. If the above snippets were used in conjunction, prod.env would be loaded while .env would be ignored.

Even if it were the right behavior, and I remove env_file=(".env", ".env.prod"), from the model_config instantiation, it still doesn't work. I just get settings.model_config.get('env_file') = None instead.

[hramezani]

Thanks @bthorsted for clarification.

I think the above-mentioned documentation is talking about the env files values. So, it means the values in the env file passed by _env_file will override... . I agree that the wording is not correct and can be improved.

[bthorsted]

@hramezani, I think that sounds counterintuitive, but even if that was the intended behavior, it still does not work.

I discovered this bug because the values in .env.test was not being read instead of the values in .env and the only explanation I could find was that _env_file had no effect, regardless of whether I specified the env_file argument in model_config or not.

[hramezani]

I created a minimal example, and it worked as expected.

from pydantic_settings import BaseSettings, SettingsConfigDict

class Settings(BaseSettings):
    foo: str

    model_config = SettingsConfigDict(env_file=".env")

settings = Settings(_env_file=".env.test")
print(settings)

.env:

FOO="foo"

.env.test:

FOO="foo-test"

and it prints foo='foo-test' as expected.

if I don't pass _env_file it prints foo='foo'

Are you sure you don't have an environment variable with the same name?