ruff/docs/rules/yield-in-init.md

yield-in-init (PLE0100)

Derived from the Pylint linter.

What it does

Checks for __init__ methods that are turned into generators by the inclusion of yield or yield from expressions.

Why is this bad?

The __init__ method is the constructor for a given Python class, responsible for initializing, rather than creating, new objects.

The __init__ method has to return None. By including a yield or yield from expression in an __init__, the method will return a generator object when called at runtime, resulting in a runtime error.

Example

class InitIsGenerator:
    def __init__(self, i):
        yield i

References

• py-init-method-is-generator