[nishusheth]

Fixes #6317

[suhaibmujahid]

Instead of storing the env var names in the config class, the config class should hold the values themselves. Resolving env vars isn't the job of configure(), and moving that responsibility out gives us more flexibility to customize validation as needed.

I would make WifConfig an interface (i.e., inherit from Protocol). Then, for each provider, I would create a pydantic_settings model that maps env vars to its fields via a prefix configuration. Where a field name doesn't match the env var name after the prefix, we can use an alias on that field.

[suhaibmujahid]

This isn't quite what I had in mind. We don't need os.environ here at all, since pydantic_settings should handle that for us.

When the environment variable name doesn't match the field name in the provider-specific model, we can use Field() with an alias to customize it. For example:

Suggested change

	token_file_env: ClassVar[str] = "OPENAI_IDENTITY_TOKEN_FILE"
	token_file: Annotated[str, Field(validation_alias="OPENAI_IDENTITY_TOKEN_FILE")]

To support both embedding in existing settings and standalone settings, we can use the from_env() pattern:

bugbug/libs/phabricator-client/phabricator_client/config.py

Lines 21 to 23 in 1bfdce8

	@classmethod
	def from_env(cls) -> PhabricatorSettings:
	return _PhabricatorEnvSettings()