RUF012 warns for pydantic.v1.main.BaseModel

[justin-snyder-slgg]

Summary

The folks at Pydantic somewhat recently added an alternate migration path which allows you to use v1 from v2.

Ruff does not correctly identify this case as a valid exception to RUF012

Example:

from pydantic.v1.main import BaseModel

class Foo(BaseModel):
    bar: list[str] = ['baz']  # <- triggers RUF012

Fix:

from pydantic.v1 import BaseModel  # removing the .main here works

class Foo(BaseModel):
    bar: list[str] = ['baz']  # <- triggers RUF012

Perhaps it would be a good idea to add a setting to mark exceptions to this rule...

Or maybe there's another rule I should activate to force the simpler import since pyright is still really bad at prioritizing the right import paths (often suggesting indirect imports through third party libraries or subpackages even when stuff is exposed from the top level module of a library)

Version

No response

[ntBre]

Hmm, yeah I'm surprised we don't expose a setting for this. I thought extend-immutable-calls would apply here, but we pass an empty list of additional calls here instead of reusing the bugbear setting in the shared helper:

ruff/crates/ruff_linter/src/rules/ruff/rules/mutable_class_default.rs

Line 121 in 6216e66

&& !is_immutable_annotation(annotation, checker.semantic(), &[])

Instead we use this helper with several different pydantic exceptions:

ruff/crates/ruff_linter/src/rules/ruff/helpers.rs

Lines 210 to 219 in 6216e66

	[
	"pydantic",
	"BaseModel" | "RootModel" | "BaseSettings" | "BaseConfig"
	] | ["pydantic", "generics", "GenericModel"]
	| [
	"pydantic",
	"v1",
	"BaseModel" | "BaseSettings" | "BaseConfig"
	]
	| ["pydantic", "v1", "generics", "GenericModel"]