Code-smell baseline

A fixed set of common code smells, drawn from Martin Fowler’s Refactoring (chapter 3). The Standards axis carries this baseline even when a repo documents nothing of its own. Two rules bind it:

• The repo overrides. A documented repo convention always wins; where it endorses something the baseline would flag, suppress the smell.
• Always a judgement call. Each smell is a labelled heuristic (“possible Feature Envy”), never a hard violation - and, like any standard, skip anything the repo’s tooling already enforces.

Each smell reads what it is → how to fix. Match each against the diff under review:

• Mysterious Name - a function, variable, or type whose name doesn’t reveal what it does or holds. → Rename it; if no honest name comes, the design is murky.
• Duplicated Code - the same logic shape appears in more than one hunk or file in the change. → Extract the shared shape and call it from both.
• Feature Envy - a method that reaches into another object’s data more than its own. → Move the method onto the data it envies.
• Data Clumps - the same few fields or parameters keep travelling together (a type wanting to be born). → Bundle them into one type and pass that.
• Primitive Obsession - a primitive or string standing in for a domain concept that deserves its own type. → Give the concept its own small type.
• Repeated Switches - the same switch or if-cascade on the same type recurs across the change. → Replace with polymorphism, or one map both sites share.
• Shotgun Surgery - one logical change forces scattered edits across many files in the diff. → Gather what changes together into one module.
• Divergent Change - one file or module is edited for several unrelated reasons. → Split it so each module changes for one reason.
• Speculative Generality - abstraction, parameters, or hooks added for needs the spec doesn’t have. → Delete it; inline back until a real need shows.
• Message Chains - long a.b().c().d() navigation the caller shouldn’t depend on. → Hide the walk behind one method on the first object.
• Middle Man - a class or function that mostly just delegates onward. → Cut it and call the real target directly.
• Refused Bequest - a subclass or implementer that ignores or overrides most of what it inherits. → Drop the inheritance and use composition.

Last updated Oct 08, 2026