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Naming Rule Set

The naming ruleset contains rules which assert the naming of different parts of the codebase.

BooleanPropertyNaming​

Reports boolean property names that do not follow the specified naming convention.

Active by default: No

Requires Type Resolution

Configuration options:​

  • allowedPattern (default: '^(is|has|are)')

    naming pattern

Noncompliant Code:​

val progressBar: Boolean = true

Compliant Code:​

val hasProgressBar: Boolean = true

ClassNaming​

Reports class or object names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Aliases: ClassName

Configuration options:​

  • classPattern (default: '[A-Z][a-zA-Z0-9]*')

    naming pattern

ConstructorParameterNaming​

Reports constructor parameter names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Configuration options:​

  • parameterPattern (default: '[a-z][A-Za-z0-9]*')

    naming pattern

  • privateParameterPattern (default: '[a-z][A-Za-z0-9]*')

    naming pattern

  • excludeClassPattern (default: '$^')

    ignores variables in classes which match this regex

EnumNaming​

Reports enum names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Aliases: EnumEntryName

Configuration options:​

  • enumEntryPattern (default: '[A-Z][_a-zA-Z0-9]*')

    naming pattern

ForbiddenClassName​

Reports class names which are forbidden per configuration. By default, this rule does not report any classes. Examples for forbidden names might be too generic class names like ...Manager.

Active by default: No

Configuration options:​

  • forbiddenName (default: [])

    forbidden class names

FunctionNameMaxLength​

Reports when very long function names are used.

Active by default: No

Aliases: FunctionMaxNameLength

Configuration options:​

  • maximumFunctionNameLength (default: 30)

    maximum name length

FunctionNameMinLength​

Reports when very short function names are used.

Active by default: No

Aliases: FunctionMinNameLength

Configuration options:​

  • minimumFunctionNameLength (default: 3)

    minimum name length

FunctionNaming​

Reports function names that do not follow the specified naming convention. One exception are factory functions used to create instances of classes. These factory functions can have the same name as the class being created.

Active by default: Yes - Since v1.0.0

Aliases: FunctionName

Configuration options:​

  • functionPattern (default: '[a-z][a-zA-Z0-9]*')

    naming pattern

  • excludeClassPattern (default: '$^')

    ignores functions in classes which match this regex

FunctionParameterNaming​

Reports function parameter names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Configuration options:​

  • parameterPattern (default: '[a-z][A-Za-z0-9]*')

    naming pattern

  • excludeClassPattern (default: '$^')

    ignores variables in classes which match this regex

InvalidPackageDeclaration​

Reports when the file location does not match the declared package.

Active by default: Yes - Since v1.21.0

Aliases: PackageDirectoryMismatch

Configuration options:​

  • rootPackage (default: '')

    if specified this part of the package structure is ignored

  • requireRootInDeclaration (default: false)

    requires the declaration to start with the specified rootPackage

LambdaParameterNaming​

Reports lambda parameter names that do not follow the specified naming convention.

Active by default: No

Configuration options:​

  • parameterPattern (default: '[a-z][A-Za-z0-9]*|_')

    naming pattern

MatchingDeclarationName​

"If a Kotlin file contains a single non-private class (potentially with related top-level declarations), its name should be the same as the name of the class, with the .kt extension appended. If a file contains multiple classes, or only top-level declarations, choose a name describing what the file contains, and name the file accordingly. Use camel humps with an uppercase first letter (e.g. ProcessDeclarations.kt).

The name of the file should describe what the code in the file does. Therefore, you should avoid using meaningless words such as "Util" in file names." - Official Kotlin Style Guide

More information at: https://kotlinlang.org/docs/coding-conventions.html

Active by default: Yes - Since v1.0.0

Configuration options:​

  • mustBeFirst (default: true)

    name should only be checked if the file starts with a class or object

  • multiplatformTargets (default: ['ios', 'android', 'js', 'jvm', 'native', 'iosArm64', 'iosX64', 'macosX64', 'mingwX64', 'linuxX64'])

    kotlin multiplatform targets, used to allow file names like MyClass.jvm.kt

Noncompliant Code:​

class Foo // FooUtils.kt

fun Bar.toFoo(): Foo = ...
fun Foo.toBar(): Bar = ...

Compliant Code:​

class Foo { // Foo.kt
    fun stuff() = 42
}

fun Bar.toFoo(): Foo = ...

MemberNameEqualsClassName​

This rule reports a member that has the same name as the containing class or object. This might result in confusion. The member should either be renamed or changed to a constructor. Factory functions that create an instance of the class are exempt from this rule.

Active by default: Yes - Since v1.2.0

Requires Type Resolution

Configuration options:​

  • ignoreOverridden (default: true)

    if overridden functions and properties should be ignored

Noncompliant Code:​

class MethodNameEqualsClassName {

    fun methodNameEqualsClassName() { }
}

class PropertyNameEqualsClassName {

    val propertyEqualsClassName = 0
}

Compliant Code:​

class Manager {

    companion object {
        // factory functions can have the same name as the class
        fun manager(): Manager {
            return Manager()
        }
    }
}

NoNameShadowing​

Disallows shadowing variable declarations. Shadowing makes it impossible to access a variable with the same name in the scope.

Active by default: Yes - Since v1.21.0

Requires Type Resolution

Noncompliant Code:​

fun test(i: Int, j: Int, k: Int) {
    val i = 1
    val (j, _) = 1 to 2
    listOf(1).map { k -> println(k) }
    listOf(1).forEach {
        listOf(2).forEach {
        }
    }
}

Compliant Code:​

fun test(i: Int, j: Int, k: Int) {
    val x = 1
    val (y, _) = 1 to 2
    listOf(1).map { z -> println(z) }
    listOf(1).forEach {
        listOf(2).forEach { x ->
        }
    }
}

NonBooleanPropertyPrefixedWithIs​

Reports when property with 'is' prefix doesn't have a boolean type. Please check chapter 8.3.2 on the Java Language Specification

Active by default: No

Requires Type Resolution

Noncompliant Code:​

val isEnabled: Int = 500

Compliant Code:​

val isEnabled: Boolean = false

ObjectPropertyNaming​

Reports property names inside objects that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Aliases: ObjectPropertyName

Configuration options:​

  • constantPattern (default: '[A-Za-z][_A-Za-z0-9]*')

    naming pattern

  • propertyPattern (default: '[A-Za-z][_A-Za-z0-9]*')

    naming pattern

  • privatePropertyPattern (default: '(_)?[A-Za-z][_A-Za-z0-9]*')

    naming pattern

PackageNaming​

Reports package names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Aliases: PackageName

Configuration options:​

  • packagePattern (default: '[a-z]+(\.[a-z][A-Za-z0-9]*)*')

    naming pattern

TopLevelPropertyNaming​

Reports top level property names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Configuration options:​

  • constantPattern (default: '[A-Z][_A-Z0-9]*')

    naming pattern

  • propertyPattern (default: '[A-Za-z][_A-Za-z0-9]*')

    naming pattern

  • privatePropertyPattern (default: '_?[A-Za-z][_A-Za-z0-9]*')

    naming pattern

VariableMaxLength​

Reports when very long variable names are used.

Active by default: No

Configuration options:​

  • maximumVariableNameLength (default: 64)

    maximum name length

VariableMinLength​

Reports when very short variable names are used.

Active by default: No

Configuration options:​

  • minimumVariableNameLength (default: 1)

    minimum name length

VariableNaming​

Reports variable names that do not follow the specified naming convention.

Active by default: Yes - Since v1.0.0

Aliases: PropertyName

Configuration options:​

  • variablePattern (default: '[a-z][A-Za-z0-9]*')

    naming pattern

  • privateVariablePattern (default: '(_)?[a-z][A-Za-z0-9]*')

    naming pattern

  • excludeClassPattern (default: '$^')

    ignores variables in classes which match this regex