Add contains_over_range_not_nil rule, make `contains_over_first_not…

…_nil` also match == nil (realm#2811)
dchohfi · Sep 3, 2019 · 2c07615 · 2c07615
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -53,6 +53,14 @@ This is the last release to support building with Swift 4.2.x.
   [Colton Schlosser](https://github.com/cltnschlosser)
   [#2807](https://github.com/realm/SwiftLint/issues/2807)
 
+* Add `contains_over_range_nil_comparison` opt-in rule to prefer
+  using `contains` over comparison of `range(of:)` to `nil`.  
+  [Colton Schlosser](https://github.com/cltnschlosser)
+  [#2776](https://github.com/realm/SwiftLint/issues/2776)
+
+* Make `contains_over_first_not_nil` rule also match `first(where:) == nil`.  
+  [Colton Schlosser](https://github.com/cltnschlosser)
+
 #### Bug Fixes
 
 * Fixed false positive in `colon` rule inside guard and ternary operator.  

diff --git a/Rules.md b/Rules.md
@@ -19,6 +19,7 @@
 * [Contains Over Filter Count](#contains-over-filter-count)
 * [Contains Over Filter Is Empty](#contains-over-filter-is-empty)
 * [Contains over first not nil](#contains-over-first-not-nil)
+* [Contains over range(of:) comparison to nil](#contains-over-rangeof-comparison-to-nil)
 * [Control Statement](#control-statement)
 * [Convenience Type](#convenience-type)
 * [Custom Rules](#custom-rules)
@@ -2807,6 +2808,36 @@ let firstIndex = myList.firstIndex { $0 % 2 == 0 }
 
 ```
 
+```swift
+↓myList.first { $0 % 2 == 0 } == nil
+
+```
+
+```swift
+↓myList.first(where: { $0 % 2 == 0 }) == nil
+
+```
+
+```swift
+↓myList.map { $0 + 1 }.first(where: { $0 % 2 == 0 }) == nil
+
+```
+
+```swift
+↓myList.first(where: someFunction) == nil
+
+```
+
+```swift
+↓myList.map { $0 + 1 }.first { $0 % 2 == 0 } == nil
+
+```
+
+```swift
+(↓myList.first { $0 % 2 == 0 }) == nil
+
+```
+
 ```swift
 ↓myList.firstIndex { $0 % 2 == 0 } != nil
 
@@ -2837,6 +2868,81 @@ let firstIndex = myList.firstIndex { $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>
+
+
+
+## Contains over range(of:) comparison to nil
+
+Identifier | Enabled by default | Supports autocorrection | Kind | Analyzer | Minimum Swift Compiler Version
+--- | --- | --- | --- | --- | ---
+`contains_over_range_nil_comparison` | Disabled | No | performance | No | 3.0.0 
+
+Prefer `contains` over `range(of:) != nil` and `range(of:) == nil`.
+
+### Examples
+
+<details>
+<summary>Non Triggering Examples</summary>
+
+```swift
+let range = myString.range(of: "Test")
+```
+
+```swift
+myString.contains("Test")
+```
+
+```swift
+!myString.contains("Test")
+```
+
+```swift
+resourceString.range(of: rule.regex, options: .regularExpression) != nil
+```
+
+</details>
+<details>
+<summary>Triggering Examples</summary>
+
+```swift
+↓myString.range(of: "Test") != nil
+```
+
+```swift
+↓myString.range(of: "Test") == nil
+```
+
 </details>
 
 

diff --git a/Source/SwiftLintFramework/Models/MasterRuleList.swift b/Source/SwiftLintFramework/Models/MasterRuleList.swift
@@ -20,6 +20,7 @@ public let masterRuleList = RuleList(rules: [
     ContainsOverFilterCountRule.self,
     ContainsOverFilterIsEmptyRule.self,
     ContainsOverFirstNotNilRule.self,
+    ContainsOverRangeNilComparisonRule.self,
     ControlStatementRule.self,
     ConvenienceTypeRule.self,
     CustomRules.self,

diff --git a/Source/SwiftLintFramework/Rules/Performance/ContainsOverFirstNotNilRule.swift b/Source/SwiftLintFramework/Rules/Performance/ContainsOverFirstNotNilRule.swift
@@ -17,19 +17,21 @@ public struct ContainsOverFirstNotNilRule: CallPairRule, OptInRule, Configuratio
             ]
         },
         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"
-            ]
+            return ["!=", "=="].flatMap { comparison in
+                return [
+                    "↓myList.\(method) { $0 % 2 == 0 } \(comparison) nil\n",
+                    "↓myList.\(method)(where: { $0 % 2 == 0 }) \(comparison) nil\n",
+                    "↓myList.map { $0 + 1 }.\(method)(where: { $0 % 2 == 0 }) \(comparison) nil\n",
+                    "↓myList.\(method)(where: someFunction) \(comparison) nil\n",
+                    "↓myList.map { $0 + 1 }.\(method) { $0 % 2 == 0 } \(comparison) nil\n",
+                    "(↓myList.\(method) { $0 % 2 == 0 }) \(comparison) nil\n"
+                ]
+            }
         }
     )
 
     public func validate(file: File) -> [StyleViolation] {
-        let pattern = "[\\}\\)]\\s*!=\\s*nil"
+        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`")

diff --git a/Source/SwiftLintFramework/Rules/Performance/ContainsOverRangeNilComparisonRule.swift b/Source/SwiftLintFramework/Rules/Performance/ContainsOverRangeNilComparisonRule.swift
@@ -0,0 +1,35 @@
+import SourceKittenFramework
+
+public struct ContainsOverRangeNilComparisonRule: CallPairRule, OptInRule, ConfigurationProviderRule,
+                                                  AutomaticTestableRule {
+    public var configuration = SeverityConfiguration(.warning)
+
+    public init() {}
+
+    public static let description = RuleDescription(
+        identifier: "contains_over_range_nil_comparison",
+        name: "Contains over range(of:) comparison to nil",
+        description: "Prefer `contains` over `range(of:) != nil` and `range(of:) == nil`.",
+        kind: .performance,
+        nonTriggeringExamples: [
+            "let range = myString.range(of: \"Test\")",
+            "myString.contains(\"Test\")",
+            "!myString.contains(\"Test\")",
+            "resourceString.range(of: rule.regex, options: .regularExpression) != nil"
+        ],
+        triggeringExamples: ["!=", "=="].flatMap { comparison in
+            return [
+                "↓myString.range(of: \"Test\") \(comparison) nil"
+            ]
+        }
+    )
+
+    public func validate(file: File) -> [StyleViolation] {
+        let pattern = "\\)\\s*(==|!=)\\s*nil"
+        return validate(file: file, pattern: pattern, patternSyntaxKinds: [.keyword],
+                        callNameSuffix: ".range", severity: configuration.severity,
+                        reason: "Prefer `contains` over range(of:) comparison to nil") { expression in
+                            return expression.enclosedArguments.map { $0.name } == ["of"]
+        }
+    }
+}
diff --git a/SwiftLint.xcodeproj/project.pbxproj b/SwiftLint.xcodeproj/project.pbxproj
@@ -91,6 +91,7 @@
 		4DCB8E7F1CBE494E0070FCF0 /* RegexHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4DCB8E7D1CBE43640070FCF0 /* RegexHelpers.swift */; };
 		4E342B4C2215C793008E4EF8 /* ReduceBooleanRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E342B4A2215C6DF008E4EF8 /* ReduceBooleanRule.swift */; };
 		550DA0E022DB95AD00B67F03 /* EmptyCollectionLiteralRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 550DA0DE22DB958400B67F03 /* EmptyCollectionLiteralRule.swift */; };
+		55CE0585231899100023BA72 /* ContainsOverRangeNilComparisonRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 550DA0E122DB9E6B00B67F03 /* ContainsOverRangeNilComparisonRule.swift */; };
 		57ED827B1CF656E3002B3513 /* JUnitReporter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 57ED82791CF65183002B3513 /* JUnitReporter.swift */; };
 		584B0D3A2112BA78002F7E25 /* SonarQubeReporter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 584B0D392112BA78002F7E25 /* SonarQubeReporter.swift */; };
 		584B0D3C2112E8FB002F7E25 /* CannedSonarQubeReporterOutput.json in Resources */ = {isa = PBXBuildFile; fileRef = 584B0D3B2112E8FB002F7E25 /* CannedSonarQubeReporterOutput.json */; };
@@ -571,6 +572,7 @@
 		5499CA961A2394B700783309 /* Components.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Components.plist; sourceTree = "<group>"; };
 		5499CA971A2394B700783309 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		550DA0DE22DB958400B67F03 /* EmptyCollectionLiteralRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EmptyCollectionLiteralRule.swift; sourceTree = "<group>"; };
+		550DA0E122DB9E6B00B67F03 /* ContainsOverRangeNilComparisonRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContainsOverRangeNilComparisonRule.swift; sourceTree = "<group>"; };
 		57ED82791CF65183002B3513 /* JUnitReporter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = JUnitReporter.swift; sourceTree = "<group>"; };
 		584B0D392112BA78002F7E25 /* SonarQubeReporter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SonarQubeReporter.swift; sourceTree = "<group>"; };
 		584B0D3B2112E8FB002F7E25 /* CannedSonarQubeReporterOutput.json */ = {isa = PBXFileReference; lastKnownFileType = text.json; path = CannedSonarQubeReporterOutput.json; sourceTree = "<group>"; };
@@ -1081,6 +1083,7 @@
 				29AD4C641F6EA16C009B66E1 /* ContainsOverFirstNotNilRule.swift */,
 				D489B546231233490090BAA0 /* ContainsOverFilterCountRule.swift */,
 				D489B549231383350090BAA0 /* ContainsOverFilterIsEmptyRule.swift */,
+				550DA0E122DB9E6B00B67F03 /* ContainsOverRangeNilComparisonRule.swift */,
 				550DA0DE22DB958400B67F03 /* EmptyCollectionLiteralRule.swift */,
 				E847F0A81BFBBABD00EA9363 /* EmptyCountRule.swift */,
 				740DF1AF203F5AFC0081F694 /* EmptyStringRule.swift */,
@@ -2065,6 +2068,7 @@
 				D4130D991E16CC1300242361 /* TypeNameRuleExamples.swift in Sources */,
 				24E17F721B14BB3F008195BE /* File+Cache.swift in Sources */,
 				C3D23F1D21E3A33700E9BD1B /* UnusedControlFlowLabelRule.swift in Sources */,
+				55CE0585231899100023BA72 /* ContainsOverRangeNilComparisonRule.swift in Sources */,
 				6C1D763221A4E69600DEF783 /* Request+DisableSourceKit.swift in Sources */,
 				47ACC8981E7DC74E0088EEB2 /* ImplicitlyUnwrappedOptionalConfiguration.swift in Sources */,
 				787CDE39208E7D41005F3D2F /* SwitchCaseAlignmentConfiguration.swift in Sources */,

diff --git a/Tests/LinuxMain.swift b/Tests/LinuxMain.swift
@@ -214,6 +214,12 @@ extension ContainsOverFirstNotNilRuleTests {
     ]
 }
 
+extension ContainsOverRangeNilComparisonRuleTests {
+    static var allTests: [(String, (ContainsOverRangeNilComparisonRuleTests) -> () throws -> Void)] = [
+        ("testWithDefaultConfiguration", testWithDefaultConfiguration)
+    ]
+}
+
 extension ControlStatementRuleTests {
     static var allTests: [(String, (ControlStatementRuleTests) -> () throws -> Void)] = [
         ("testWithDefaultConfiguration", testWithDefaultConfiguration)
@@ -1577,6 +1583,7 @@ XCTMain([
     testCase(ContainsOverFilterCountRuleTests.allTests),
     testCase(ContainsOverFilterIsEmptyRuleTests.allTests),
     testCase(ContainsOverFirstNotNilRuleTests.allTests),
+    testCase(ContainsOverRangeNilComparisonRuleTests.allTests),
     testCase(ControlStatementRuleTests.allTests),
     testCase(ConvenienceTypeRuleTests.allTests),
     testCase(CustomRulesTests.allTests),

diff --git a/Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift b/Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift
@@ -78,6 +78,12 @@ class ContainsOverFilterIsEmptyRuleTests: XCTestCase {
     }
 }
 
+class ContainsOverRangeNilComparisonRuleTests: XCTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(ContainsOverRangeNilComparisonRule.description)
+    }
+}
+
 class ControlStatementRuleTests: XCTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(ControlStatementRule.description)