contains_over_first_not_nil rule now also checks for firstIndex(where:)

CHANGELOG.md

@@ -39,6 +39,10 @@
   [Matthew Healy](https://github.com/matthew-healy)
   [#2595](https://github.com/realm/SwiftLint/2595)
 
+* `contains_over_first_not_nil` rule now also checks for `firstIndex(where:)`.  
+  [Marcelo Fabri](https://github.com/marcelofabri)
+  [#2678](https://github.com/realm/SwiftLint/issues/2678)
+
 #### Bug Fixes
 
 * Fix bug where SwiftLint ignores excluded files list in a nested configuration

Rules.md

@@ -2519,7 +2519,7 @@ Identifier | Enabled by default | Supports autocorrection | Kind | Analyzer | Mi
 --- | --- | --- | --- | --- | ---
 `contains_over_first_not_nil` | Disabled | No | performance | No | 3.0.0 
 
-Prefer `contains` over `first(where:) != nil`
+Prefer `contains` over `first(where:) != nil` and `firstIndex(where:) != nil`.
 
 ### Examples
 
@@ -2536,6 +2536,16 @@ let first = myList.first { $0 % 2 == 0 }
 
 ```
 
+```swift
+let firstIndex = myList.firstIndex(where: { $0 % 2 == 0 })
+
+```
+
+```swift
+let firstIndex = myList.firstIndex { $0 % 2 == 0 }
+
+```
+
 </details>
 <details>
 <summary>Triggering Examples</summary>
@@ -2570,6 +2580,36 @@ let first = myList.first { $0 % 2 == 0 }
 
 ```
 
+```swift
+↓myList.firstIndex { $0 % 2 == 0 } != nil
+
+```
+
+```swift
+↓myList.firstIndex(where: { $0 % 2 == 0 }) != nil
+
+```
+
+```swift
+↓myList.map { $0 + 1 }.firstIndex(where: { $0 % 2 == 0 }) != nil
+
+```
+
+```swift
+↓myList.firstIndex(where: someFunction) != nil
+
+```
+
+```swift
+↓myList.map { $0 + 1 }.firstIndex { $0 % 2 == 0 } != nil
+
+```
+
+```swift
+(↓myList.firstIndex { $0 % 2 == 0 }) != nil
+
+```
+
 </details>
 
 

Source/SwiftLintFramework/Protocols/CallPairRule.swift

@@ -23,13 +23,15 @@ extension CallPairRule {
         - patternSyntaxKinds: Syntax kinds matches should have
         - callNameSuffix: Suffix of the first method call name
         - severity: Severity of violations
+        - reason: The reason of the generated violations
         - predicate: Predicate to apply after checking callNameSuffix
      */
     internal func validate(file: File,
                            pattern: String,
                            patternSyntaxKinds: [SyntaxKind],
                            callNameSuffix: String,
                            severity: ViolationSeverity,
+                           reason: String? = nil,
                            predicate: ([String: SourceKitRepresentable]) -> Bool = { _ in true }) -> [StyleViolation] {
         let firstRanges = file.match(pattern: pattern, with: patternSyntaxKinds)
         let contents = file.contents.bridge()
@@ -59,7 +61,8 @@ extension CallPairRule {
         return violatingLocations.map {
             StyleViolation(ruleDescription: type(of: self).description,
                            severity: severity,
-                           location: Location(file: file, byteOffset: $0))
+                           location: Location(file: file, byteOffset: $0),
+                           reason: reason)
         }
     }
 

Source/SwiftLintFramework/Rules/Performance/ContainsOverFirstNotNilRule.swift

@@ -1,34 +1,42 @@
 import SourceKittenFramework
 
-public struct ContainsOverFirstNotNilRule: CallPairRule, OptInRule, ConfigurationProviderRule, AutomaticTestableRule {
+public struct ContainsOverFirstNotNilRule: CallPairRule, OptInRule, ConfigurationProviderRule {
     public var configuration = SeverityConfiguration(.warning)
 
     public init() {}
 
     public static let description = RuleDescription(
         identifier: "contains_over_first_not_nil",
         name: "Contains over first not nil",
-        description: "Prefer `contains` over `first(where:) != nil`",
+        description: "Prefer `contains` over `first(where:) != nil` and `firstIndex(where:) != nil`.",
         kind: .performance,
-        nonTriggeringExamples: [
-            "let first = myList.first(where: { $0 % 2 == 0 })\n",
-            "let first = myList.first { $0 % 2 == 0 }\n"
-        ],
-        triggeringExamples: [
-            "↓myList.first { $0 % 2 == 0 } != nil\n",
-            "↓myList.first(where: { $0 % 2 == 0 }) != nil\n",
-            "↓myList.map { $0 + 1 }.first(where: { $0 % 2 == 0 }) != nil\n",
-            "↓myList.first(where: someFunction) != nil\n",
-            "↓myList.map { $0 + 1 }.first { $0 % 2 == 0 } != nil\n",
-            "(↓myList.first { $0 % 2 == 0 }) != nil\n"
-        ]
+        nonTriggeringExamples: ["first", "firstIndex"].flatMap { method in
+            return [
+                "let \(method) = myList.\(method)(where: { $0 % 2 == 0 })\n",
+                "let \(method) = myList.\(method) { $0 % 2 == 0 }\n"
+            ]
+        },
+        triggeringExamples: ["first", "firstIndex"].flatMap { method in
+            return [
+                "↓myList.\(method) { $0 % 2 == 0 } != nil\n",
+                "↓myList.\(method)(where: { $0 % 2 == 0 }) != nil\n",
+                "↓myList.map { $0 + 1 }.\(method)(where: { $0 % 2 == 0 }) != nil\n",
+                "↓myList.\(method)(where: someFunction) != nil\n",
+                "↓myList.map { $0 + 1 }.\(method) { $0 % 2 == 0 } != nil\n",
+                "(↓myList.\(method) { $0 % 2 == 0 }) != nil\n"
+            ]
+        }
     )
 
     public func validate(file: File) -> [StyleViolation] {
-        return validate(file: file,
-                        pattern: "[\\}\\)]\\s*!=\\s*nil",
-                        patternSyntaxKinds: [.keyword],
-                        callNameSuffix: ".first",
-                        severity: configuration.severity)
+        let pattern = "[\\}\\)]\\s*!=\\s*nil"
+        let firstViolations = validate(file: file, pattern: pattern, patternSyntaxKinds: [.keyword],
+                                       callNameSuffix: ".first", severity: configuration.severity,
+                                       reason: "Prefer `contains` over `first(where:) != nil`")
+        let firstIndexViolations = validate(file: file, pattern: pattern, patternSyntaxKinds: [.keyword],
+                                            callNameSuffix: ".firstIndex", severity: configuration.severity,
+                                            reason: "Prefer `contains` over `firstIndex(where:) != nil`")
+
+        return firstViolations + firstIndexViolations
     }
 }

SwiftLint.xcodeproj/project.pbxproj

@@ -332,6 +332,7 @@
 		D4DABFD91E2C59BC009617B6 /* NotificationCenterDetachmentRuleExamples.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4DABFD81E2C59BC009617B6 /* NotificationCenterDetachmentRuleExamples.swift */; };
 		D4DAE8BC1DE14E8F00B0AE7A /* NimbleOperatorRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4DAE8BB1DE14E8F00B0AE7A /* NimbleOperatorRule.swift */; };
 		D4DB92251E628898005DE9C1 /* TodoRuleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4DB92241E628898005DE9C1 /* TodoRuleTests.swift */; };
+		D4DDFF9822396D62006C3629 /* ContainsOverFirstNotNilRuleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4DDFF9722396D62006C3629 /* ContainsOverFirstNotNilRuleTests.swift */; };
 		D4DE9133207B4750000FFAA8 /* UnavailableFunctionRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4DE9131207B4731000FFAA8 /* UnavailableFunctionRule.swift */; };
 		D4E2BA851F6CD77B00E8E184 /* ArrayInitRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4E2BA841F6CD77B00E8E184 /* ArrayInitRule.swift */; };
 		D4E92D1F2137B4C9002EDD48 /* IdenticalOperandsRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = D4E92D1E2137B4C9002EDD48 /* IdenticalOperandsRule.swift */; };
@@ -817,6 +818,7 @@
 		D4DABFD81E2C59BC009617B6 /* NotificationCenterDetachmentRuleExamples.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NotificationCenterDetachmentRuleExamples.swift; sourceTree = "<group>"; };
 		D4DAE8BB1DE14E8F00B0AE7A /* NimbleOperatorRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NimbleOperatorRule.swift; sourceTree = "<group>"; };
 		D4DB92241E628898005DE9C1 /* TodoRuleTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TodoRuleTests.swift; sourceTree = "<group>"; };
+		D4DDFF9722396D62006C3629 /* ContainsOverFirstNotNilRuleTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContainsOverFirstNotNilRuleTests.swift; sourceTree = "<group>"; };
 		D4DE9131207B4731000FFAA8 /* UnavailableFunctionRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UnavailableFunctionRule.swift; sourceTree = "<group>"; };
 		D4E2BA841F6CD77B00E8E184 /* ArrayInitRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ArrayInitRule.swift; sourceTree = "<group>"; };
 		D4E92D1E2137B4C9002EDD48 /* IdenticalOperandsRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IdenticalOperandsRule.swift; sourceTree = "<group>"; };
@@ -1415,6 +1417,7 @@
 				E809EDA21B8A73FB00399043 /* ConfigurationTests.swift */,
 				F480DC7E1F26090000099465 /* ConfigurationTests+Nested.swift */,
 				F480DC821F2609D700099465 /* ConfigurationTests+ProjectMock.swift */,
+				D4DDFF9722396D62006C3629 /* ContainsOverFirstNotNilRuleTests.swift */,
 				3BB47D861C51DE6E00AE6A10 /* CustomRulesTests.swift */,
 				67932E2C1E54AF4B00CB0629 /* CyclomaticComplexityConfigurationTests.swift */,
 				67EB4DFB1E4CD7F5004E9ACD /* CyclomaticComplexityRuleTests.swift */,
@@ -2198,6 +2201,7 @@
 				3B12C9C31C320A53000B423F /* YamlSwiftLintTests.swift in Sources */,
 				D41985ED21FAD033003BE2B7 /* DeploymentTargetConfigurationTests.swift in Sources */,
 				D450D1E221F19B1E00E60010 /* TrailingClosureConfigurationTests.swift in Sources */,
+				D4DDFF9822396D62006C3629 /* ContainsOverFirstNotNilRuleTests.swift in Sources */,
 				E832F10D1B17E725003F265F /* IntegrationTests.swift in Sources */,
 				D4C27C001E12DFF500DF713E /* LinterCacheTests.swift in Sources */,
 				D45255C81F0932F8003C9B56 /* RuleDescription+Examples.swift in Sources */,

Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift

@@ -66,12 +66,6 @@ class CommaRuleTests: XCTestCase {
     }
 }
 
-class ContainsOverFirstNotNilRuleTests: XCTestCase {
-    func testWithDefaultConfiguration() {
-        verifyRule(ContainsOverFirstNotNilRule.description)
-    }
-}
-
 class ControlStatementRuleTests: XCTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(ControlStatementRule.description)

Tests/SwiftLintFrameworkTests/ContainsOverFirstNotNilRuleTests.swift

@@ -0,0 +1,36 @@
+import SwiftLintFramework
+import XCTest
+
+class ContainsOverFirstNotNilRuleTests: XCTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(ContainsOverFirstNotNilRule.description)
+    }
+
+    // MARK: - Reasons
+
+    func testFirstReason() {
+        let string = "↓myList.first { $0 % 2 == 0 } != nil"
+        let violations = self.violations(string)
+
+        XCTAssertEqual(violations.count, 1)
+        XCTAssertEqual(violations.first?.reason, "Prefer `contains` over `first(where:) != nil`")
+    }
+
+    func testFirstIndexReason() {
+        let string = "↓myList.firstIndex { $0 % 2 == 0 } != nil"
+        let violations = self.violations(string)
+
+        XCTAssertEqual(violations.count, 1)
+        XCTAssertEqual(violations.first?.reason, "Prefer `contains` over `firstIndex(where:) != nil`")
+    }
+
+    // MARK: - Private
+
+    private func violations(_ string: String, config: Any? = nil) -> [StyleViolation] {
+        guard let config = makeConfig(config, ContainsOverFirstNotNilRule.description.identifier) else {
+            return []
+        }
+
+        return SwiftLintFrameworkTests.violations(string, config: config)
+    }
+}