register_generator prevents extending existing generators

[mbissinger]

Description

The register_generator function enforces the following check:

if not isinstance(generator_class, type) or not issubclass(
    generator_class, BaseGenerator
):
    raise TypeError(
        f"Generator must inherit from BaseGenerator, got {generator_class}"
    )

This logic incorrectly rejects subclasses of existing generators, even though those generators themselves ultimately derive from BaseGenerator.
As a result, extending an existing generator (as encouraged by the documentation) is not possible via register_generator.

To Reproduce

Use the example given at example/extend_builtin_generator.py or the following snippet:

from omymodels.models.sqlalchemy_v2 import ModelGenerator as SQLAlchemyV2Generator
from omymodels.plugins import register_generator

class SQLAlchemyV2Extension(SQLAlchemyV2Generator):
    pass

register_generator(
    name="sqlalchemy_v2_extension",
    generator_class=SQLAlchemyV2Extension
)

Raises:

TypeError: Generator must inherit from BaseGenerator

Expected behavior

register_generator should accept subclasses of existing generators, as they already inherit (directly or indirectly) from BaseGenerator.

Workaround

Manually inject the generator:

from omymodels import plugins

plugins._custom_generators["sqlalchemy_v2_extension"] = SQLAlchemyV2Extension

Desktop:

• OS: Windows 11
• Python: 3.10