convention-solid-ocp

The open closed principle keeps software extensible by allowing new features to be added through new classes rather than modifying existing code. This approach reduces regression risk and simplifies testing across modular architectures.

To add new features without modifying existing code, introduce an abstract interface and create concrete extension classes. Wire them through a factory or dependency injection to enable new behavior while keeping existing implementations stable.

You need abstractions and extension points when scaling software across teams and adding new features with minimal risk. This is essential for designing library APIs, plugins, and modular architectures to prevent regressions in existing behavior.

Yes, the open closed principle reduces regression risk by enforcing that new functionality is added via new concrete implementations conforming to existing interfaces. This ensures existing code remains stable and untouched during feature expansion.

The best way to implement extensibility is by defining abstract interfaces for features and creating concrete extension classes. This strategy allows plugins and library APIs to accommodate new requirements without altering existing implementations.

You should not use the open closed principle when adding simple features that do not require abstraction or when the overhead of introducing interfaces and concrete implementations outweighs the benefit of keeping existing code untouched.