Use Params For Variable Args

csharp.use_params_for_variable_args

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

CSharp

Description

Reports public methods whose last parameter is an object[] or string[] array without the params modifier. The params modifier lets callers pass values directly (Foo(a, b, c)) instead of constructing a temporary array (Foo(new[] { a, b, c })).

Rationale

params is the .NET-idiomatic shape for variadic public APIs. It costs nothing at the callee (the array is still received as a single parameter) and removes a syntactic ceremony from every call site. Reserving it to non-public overloads makes the API harder to use without adding flexibility.

public class Bus
{
    public void Emit(string topic, object[] payload) { }              // FLAW
    public void Log(string level, string[] tags) { }                  // FLAW

    public void Push(string topic, params object[] payload) { }       // OK
    public void Combine(string topic, string format) { }              // OK, not an array
    internal void EmitInternal(string topic, object[] payload) { }    // OK, non-public
}

Remediation

Add the params modifier to the last array parameter. If the array is meant to be passed only as a constructed array (for performance reasons or because the contents are not user-supplied), document the choice and add an internal/private non-params overload.

References

params keyword