Max Params

ID

swift.max_params

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Complexity

Language

Swift

Tags

complexity

Description

Reports a function, initializer or subscript declaration whose parameter count exceeds a configurable threshold.

Configuration

  • maxParams (default 7) — counts strictly greater than this value are flagged.

Rationale

High parameter counts make a function harder to call correctly, harder to remember the order of arguments at the call site, and almost always indicate the function has accumulated unrelated responsibilities. Swift mitigates some of this with argument labels, but the cognitive load still grows: each additional parameter is one more name the caller has to know and one more value the body has to coordinate.

Notes

Closures (function literals) are intentionally excluded: their parameter counts are usually dictated by the receiver (e.g. a UIKit completion handler), not the closure body, so penalising them does not lead to a useful refactor.

Remediation

Common refactors:

  • group related parameters into a small struct (options object);

  • split the function along its independent responsibilities;

  • default arguments to make rarely-used parameters optional at the call site.

// Too many parameters.
func process(a: Int, b: Int, c: Int, d: Int,
             e: Int, f: Int, g: Int, h: Int) { ... }

// Group related values into a configuration struct.
struct Options { let a, b, c, d, e, f, g, h: Int }
func process(_ opts: Options) { ... }

References