This rule detects and reports usages of magic numbers in the code. Prefer defining constants with clear names describing what the magic number means.

Noncompliant Code

class User {

    fun checkName(name: String) {
        if (name.length > 42) {
            throw IllegalArgumentException("username is too long")
        }
        // ...
    }
}

Compliant Code

class User {

    fun checkName(name: String) {
        if (name.length > MAX_USERNAME_SIZE) {
            throw IllegalArgumentException("username is too long")
        }
        // ...
    }

    companion object {
        private const val MAX_USERNAME_SIZE = 42
    }
}

Options

• excludes (default: ['**/test/**', '**/androidTest/**', '**/commonTest/**', '**/jvmTest/**', '**/jsTest/**', '**/iosTest/**', '**/*.kts'])

  path filter

• ignoreNumbers (default: ['-1', '0', '1', '2'])

  numbers which do not count as magic numbers

• ignoreHashCodeFunction (default: True)

  whether magic numbers in hashCode functions should be ignored

• ignorePropertyDeclaration (default: False)

  whether magic numbers in property declarations should be ignored

• ignoreLocalVariableDeclaration (default: False)

  whether magic numbers in local variable declarations should be ignored

• ignoreConstantDeclaration (default: True)

  whether magic numbers in constant declarations should be ignored

• ignoreCompanionObjectPropertyDeclaration (default: True)

  whether magic numbers in companion object declarations should be ignored

• ignoreAnnotation (default: False)

  whether magic numbers in annotations should be ignored

• ignoreNamedArgument (default: True)

  whether magic numbers in named arguments should be ignored

• ignoreEnums (default: False)

  whether magic numbers in enums should be ignored

• ignoreRanges (default: False)

  whether magic numbers in ranges should be ignored

• ignoreExtensionFunctions (default: True)

  whether magic numbers as subject of an extension function should be ignored