Merge pull request #3191 from MortyMerr/feature/preferZeroRule

Add prefer_zero_over_explicit_init rule

CHANGELOG.md

@@ -33,6 +33,12 @@
   [Zsolt Kovács](https://github.com/lordzsolt)
   [#3103](https://github.com/realm/SwiftLint/issues/3103)
 
+* Add `prefer_zero_over_explicit_init` opt-in rule to enforce using
+  `.zero` instead of calling constructor with zero arguments
+  (e.g. `CGPoint(x: 0, y: 0)`) when using CoreGraphics types.  
+  [Anton Nazarov](https://github.com/MortyMerr)
+  [#3190](https://github.com/realm/SwiftLint/issues/3190)  
+
 #### Bug Fixes
 
 * Fix UnusedImportRule breaking transitive imports.  

Source/SwiftLintFramework/Models/MasterRuleList.swift

@@ -124,6 +124,7 @@ public let masterRuleList = RuleList(rules: [
     OverrideInExtensionRule.self,
     PatternMatchingKeywordsRule.self,
     PreferSelfTypeOverTypeOfSelfRule.self,
+    PreferZeroOverExplicitInitRule.self,
     PrefixedTopLevelConstantRule.self,
     PrivateActionRule.self,
     PrivateOutletRule.self,

Source/SwiftLintFramework/Rules/Idiomatic/PreferZeroOverExplicitInitRule.swift

@@ -0,0 +1,71 @@
+import Foundation
+import SourceKittenFramework
+
+public struct PreferZeroOverExplicitInitRule: OptInRule, ConfigurationProviderRule, SubstitutionCorrectableRule,
+                                              AutomaticTestableRule {
+    public var configuration = SeverityConfiguration(.warning)
+    private var pattern: String {
+        let zero = "\\s*:\\s*0(.0*)?\\s*"
+        let type = "(\(["CGPoint", "CGSize", "CGVector", "CGRect"].joined(separator: "|")))"
+        let firstArg = "(\(["x", "dx", "width"].joined(separator: "|")))"
+        let secondArg = "(\(["y", "dy", "height"].joined(separator: "|")))"
+        let thirdAndFourthArg = "(\\,\\s*width\(zero)\\,\\s*height\(zero))?"
+        return "\(type)\\(\\s*\(firstArg)\(zero)\\,\\s*\(secondArg)\(zero)\(thirdAndFourthArg)\\)"
+    }
+
+    public static let description = RuleDescription(
+        identifier: "prefer_zero_over_explicit_init",
+        name: "Prefer Zero Over Explicit Init",
+        description: "Prefer `.zero` over explicit init with zero parameters (e.g. `CGPoint(x: 0, y: 0)`)",
+        kind: .idiomatic,
+        nonTriggeringExamples: [
+            Example("CGRect(x: 0, y: 0, width: 0, height: 1)"),
+            Example("CGPoint(x: 0, y: -1"),
+            Example("CGSize(width: 2, height: 4)"),
+            Example("CGVector(dx: -5, dy: 0)")
+        ],
+        triggeringExamples: [
+            Example("↓CGPoint(x: 0, y: 0)"),
+            Example("↓CGPoint(x: 0.000000, y: 0)"),
+            Example("↓CGPoint(x: 0.000000, y: 0.000)"),
+            Example("↓CGRect(x: 0, y: 0, width: 0, height: 0)"),
+            Example("↓CGSize(width: 0, height: 0)"),
+            Example("↓CGVector(dx: 0, dy: 0)")
+        ],
+        corrections: [
+            Example("↓CGPoint(x: 0, y: 0)"): Example("CGPoint.zero"),
+            Example("↓CGRect(x: 0, y: 0, width: 0, height: 0)"): Example("CGRect.zero"),
+            Example("↓CGSize(width: 0, height: 0.000)"): Example("CGSize.zero"),
+            Example("↓CGVector(dx: 0, dy: 0)"): Example("CGVector.zero")
+        ]
+    )
+
+    public init() {}
+
+    public func validate(file: SwiftLintFile) -> [StyleViolation] {
+        violationRanges(in: file).map {
+            StyleViolation(
+                ruleDescription: Self.description,
+                severity: configuration.severity,
+                location: Location(file: file, characterOffset: $0.location)
+            )
+        }
+    }
+
+    public func violationRanges(in file: SwiftLintFile) -> [NSRange] {
+        return file.matchesAndSyntaxKinds(matching: pattern)
+            .filter {
+                $0.1 == [.identifier, .identifier, .number, .identifier, .number] ||
+                $0.1 == [
+                    .identifier, .identifier, .number, .identifier, .number, .identifier, .number, .identifier, .number
+                ]
+            }
+            .map { $0.0.range(at: 0) }
+    }
+
+    public func substitution(for violationRange: NSRange, in file: SwiftLintFile) -> (NSRange, String)? {
+        let declaration = file.stringView.substring(with: violationRange)
+        guard let typeEndIndex = declaration.firstIndex(of: "(") else { return nil }
+        return (violationRange, "\(declaration.prefix(upTo: typeEndIndex)).zero")
+    }
+}

SwiftLint.xcodeproj/project.pbxproj

@@ -164,6 +164,7 @@
 		77DFF0E923442DE30041EEB4 /* RawValueForCamelCasedCodableEnumRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7723A4DE23442D7100F38590 /* RawValueForCamelCasedCodableEnumRule.swift */; };
 		787CDE39208E7D41005F3D2F /* SwitchCaseAlignmentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 787CDE38208E7D41005F3D2F /* SwitchCaseAlignmentConfiguration.swift */; };
 		787CDE3B208F9C34005F3D2F /* SwitchCaseAlignmentRuleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 787CDE3A208F9C34005F3D2F /* SwitchCaseAlignmentRuleTests.swift */; };
+		78B9051D24564AF600C81B0A /* PreferZeroOverExplicitInitRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 78B9051A245646CD00C81B0A /* PreferZeroOverExplicitInitRule.swift */; };
 		78F032461D7C877E00BE709A /* OverriddenSuperCallRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 78F032441D7C877800BE709A /* OverriddenSuperCallRule.swift */; };
 		78F032481D7D614300BE709A /* OverridenSuperCallConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 78F032471D7D614300BE709A /* OverridenSuperCallConfiguration.swift */; };
 		7C0C2E7A1D2866CB0076435A /* ExplicitInitRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7C0C2E791D2866CB0076435A /* ExplicitInitRule.swift */; };
@@ -683,6 +684,7 @@
 		7723A4DE23442D7100F38590 /* RawValueForCamelCasedCodableEnumRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RawValueForCamelCasedCodableEnumRule.swift; sourceTree = "<group>"; };
 		787CDE38208E7D41005F3D2F /* SwitchCaseAlignmentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SwitchCaseAlignmentConfiguration.swift; sourceTree = "<group>"; };
 		787CDE3A208F9C34005F3D2F /* SwitchCaseAlignmentRuleTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SwitchCaseAlignmentRuleTests.swift; sourceTree = "<group>"; };
+		78B9051A245646CD00C81B0A /* PreferZeroOverExplicitInitRule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferZeroOverExplicitInitRule.swift; sourceTree = "<group>"; };
 		78F032441D7C877800BE709A /* OverriddenSuperCallRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OverriddenSuperCallRule.swift; sourceTree = "<group>"; };
 		78F032471D7D614300BE709A /* OverridenSuperCallConfiguration.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OverridenSuperCallConfiguration.swift; sourceTree = "<group>"; };
 		7C0C2E791D2866CB0076435A /* ExplicitInitRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ExplicitInitRule.swift; sourceTree = "<group>"; };
@@ -1381,6 +1383,7 @@
 				827169B41F48D712003FB9AF /* NoGroupingExtensionRule.swift */,
 				D4B022971E102EE8007E5297 /* ObjectLiteralRule.swift */,
 				D403A4A21F4DB5510020CA02 /* PatternMatchingKeywordsRule.swift */,
+				78B9051A245646CD00C81B0A /* PreferZeroOverExplicitInitRule.swift */,
 				1E3C2D701EE36C6F00C8386D /* PrivateOverFilePrivateRule.swift */,
 				24B4DF0B1D6DFA370097803B /* RedundantNilCoalescingRule.swift */,
 				18B90B6A21ADD99800B60749 /* RedundantObjcAttributeRule.swift */,
@@ -2356,6 +2359,7 @@
 				6C15818D237026AC00F582A2 /* GitHubActionsLoggingReporter.swift in Sources */,
 				62FE5D32200CABDD00F68793 /* DiscouragedOptionalCollectionExamples.swift in Sources */,
 				D41C09BD23C1B99D00F105C4 /* OrphanedDocCommentRule.swift in Sources */,
+				78B9051D24564AF600C81B0A /* PreferZeroOverExplicitInitRule.swift in Sources */,
 				D49896F12026B36C00814A83 /* RedundantSetAccessControlRule.swift in Sources */,
 				E4A6CF752363CBFB00DD5B18 /* RandomAccessCollection+Swiftlint.swift in Sources */,
 				29FFC37A1F15764D007E4825 /* FileLengthRuleConfiguration.swift in Sources */,

Tests/LinuxMain.swift

@@ -1094,6 +1094,12 @@ extension PreferSelfTypeOverTypeOfSelfRuleTests {
     ]
 }
 
+extension PreferZeroOverExplicitInitRuleTests {
+    static var allTests: [(String, (PreferZeroOverExplicitInitRuleTests) -> () throws -> Void)] = [
+        ("testWithDefaultConfiguration", testWithDefaultConfiguration)
+    ]
+}
+
 extension PrefixedTopLevelConstantRuleTests {
     static var allTests: [(String, (PrefixedTopLevelConstantRuleTests) -> () throws -> Void)] = [
         ("testDefaultConfiguration", testDefaultConfiguration),
@@ -1826,6 +1832,7 @@ XCTMain([
     testCase(OverrideInExtensionRuleTests.allTests),
     testCase(PatternMatchingKeywordsRuleTests.allTests),
     testCase(PreferSelfTypeOverTypeOfSelfRuleTests.allTests),
+    testCase(PreferZeroOverExplicitInitRuleTests.allTests),
     testCase(PrefixedTopLevelConstantRuleTests.allTests),
     testCase(PrivateActionRuleTests.allTests),
     testCase(PrivateOutletRuleTests.allTests),

Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift

@@ -522,6 +522,12 @@ class PreferSelfTypeOverTypeOfSelfRuleTests: XCTestCase {
     }
 }
 
+class PreferZeroOverExplicitInitRuleTests: XCTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(PreferZeroOverExplicitInitRule.description)
+    }
+}
+
 class PrivateActionRuleTests: XCTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(PrivateActionRule.description)