- rule added for avoiding redundant extensions resolve #5359

.swiftlint.yml

@@ -42,6 +42,7 @@ disabled_rules:
  - prefer_nimble
  - prefer_self_in_static_references
  - prefixed_toplevel_constant
+ - redundant_extension
  - redundant_self_in_closure
  - required_deinit
  - self_binding

CHANGELOG.md

@@ -10,6 +10,10 @@
 
 #### Enhancements
 
+* Add new `redundant_extension` rule that detect redundant extensions.
+ [Muhammad Zeeshan](https://github.com/mzeeshanid)
+ [#5359](https://github.com/realm/SwiftLint/issues/5359)
+
 * Add new `one_declaration_per_file` rule that allows only a
  single class/struct/enum/protocol declaration per file.
  Extensions are an exception; more than one is allowed. 

Source/SwiftLintBuiltInRules/Models/BuiltInRules.swift

@@ -166,6 +166,7 @@ public let builtInRules: [any Rule.Type] = [
  ReduceBooleanRule.self,
  ReduceIntoRule.self,
  RedundantDiscardableLetRule.self,
+ RedundantExtensionRule.self,
  RedundantNilCoalescingRule.self,
  RedundantObjcAttributeRule.self,
  RedundantOptionalInitializationRule.self,

Source/SwiftLintBuiltInRules/Rules/Idiomatic/RedundantExtensionRule.swift

@@ -0,0 +1,50 @@
+import SwiftSyntax
+
+@SwiftSyntaxRule
+struct RedundantExtensionRule: OptInRule {
+ var configuration = SeverityConfiguration<Self>(.warning)
+
+ static let description = RuleDescription(
+ identifier: "redundant_extension",
+ name: "Redundant Extension",
+ description: "Avoid redundant extensions",
+ kind: .idiomatic,
+ nonTriggeringExamples: [
+ Example("""
+ extension Foo {
+ func something() {}
+ }
+ """),
+ Example("""
+ extension Foo {
+ var a: Int { 1 }
+ }
+ """),
+ Example("""
+ extension Foo {
+ final class Bar {}
+ }
+ """),
+ Example("""
+ extension Foo {
+ struct Bar {}
+ }
+ """)
+ ],
+ triggeringExamples: [
+ Example("""
+ ↓extension Bar {}
+ """)
+ ]
+ )
+}
+
+private extension RedundantExtensionRule {
+ final class Visitor: ViolationsSyntaxVisitor<ConfigurationType> {
+ override func visitPost(_ node: ExtensionDeclSyntax) {
+ if node.memberBlock.members.isEmpty {
+ violations.append(node.extensionKeyword.positionAfterSkippingLeadingTrivia)
+ }
+ }
+ }
+}

Tests/GeneratedTests/GeneratedTests.swift

@@ -986,6 +986,12 @@ class RedundantDiscardableLetRuleGeneratedTests: SwiftLintTestCase {
  }
 }
 
+class RedundantExtensionRuleGeneratedTests: SwiftLintTestCase {
+ func testWithDefaultConfiguration() {
+ verifyRule(RedundantExtensionRule.description)
+ }
+}
+
 class RedundantNilCoalescingRuleGeneratedTests: SwiftLintTestCase {
  func testWithDefaultConfiguration() {
  verifyRule(RedundantNilCoalescingRule.description)