Other Smells

What these smells share

This group holds smells that cross the boundaries of the main categories. The current member concerns code you do not own. You cannot refactor a third-party or generated class directly, so the usual moves, such as adding a method where the data lives, are not available. The smell is in how your code works around that limit.

Members

• Incomplete Library Class: a library type lacks a method you need, and workarounds for it are duplicated across your code.

How to choose within this category

• If the type you want to change is yours, this is not the right category. Look at Feature Envy or Duplicate Code instead.
• If the type is from a library and you need one or two extra operations, treat it as Incomplete Library Class with Introduce Foreign Method.
• If you need many extra operations on the same library type, use Introduce Local Extension, or an Adapter when you also want to hide the library's interface.

For agents

• Check whether an installed dependency or a newer version of the library already provides the operation before writing one.
• Use the language's extension mechanism where one exists: C# extension methods, Kotlin extension functions, Swift extensions, Rust traits.
• Never patch the library's prototype or vendored source to add the method.