Add ExplicitInitRule

CHANGELOG.md

@@ -13,6 +13,11 @@
 * Adds `allow_private_set` configuration for the `private_outlet` rule.  
   [Rohan Dhaimade](https://github.com/HaloZero)
 
+* Add ``ExplicitInitRule`` Opt-In rule to discourage calling ``init``
+  directly.  
+  [Matt Taube](https://github.com/mtaube)
+  [#715](https://github.com/realm/SwiftLint/pull/715)
+
 ##### Bug Fixes
 
 * Fixed whitespace being added to TODO messages.  

Source/SwiftLintFramework/Models/MasterRuleList.swift

@@ -49,6 +49,7 @@ public let masterRuleList = RuleList(rules:
     CustomRules.self,
     CyclomaticComplexityRule.self,
     EmptyCountRule.self,
+    ExplicitInitRule.self,
     FileLengthRule.self,
     ForceCastRule.self,
     ForceTryRule.self,

Source/SwiftLintFramework/Rules/ExplicitInitRule.swift

@@ -0,0 +1,75 @@
+//
+//  ExplicitInitRule.swift
+//  SwiftLint
+//
+//  Created by Matt Taube on 7/2/16.
+//  Copyright (c) 2016 Realm. All rights reserved.
+//
+
+import Foundation
+import SourceKittenFramework
+
+public struct ExplicitInitRule: ConfigurationProviderRule, CorrectableRule, OptInRule {
+
+    private let pattern = "\\b([A-Z][A-Za-z]*)\\.init\\("
+
+    public var configuration = SeverityConfiguration(.Warning)
+
+    public init() {}
+
+    public static let description = RuleDescription(
+        identifier: "explicit_init",
+        name: "Explicit Init",
+        description: "Explicitly calling .init() should be avoided.",
+        nonTriggeringExamples: [
+            "self.init(",
+            "self.init",
+            "Abc.init",
+            "abc.init(",
+            "$0.init("
+        ],
+        triggeringExamples: [
+            "Abc.init(",
+            "Abc(NSURL.init(someString"
+        ],
+        corrections: [
+            "Abc.init(": "Abc(",
+            "Abc(NSURL.init(someString": "Abc(NSURL(someString"
+        ]
+    )
+
+    public func validateFile(file: File) -> [StyleViolation] {
+        return violationRangesInFile(file).flatMap { range in
+            return StyleViolation(ruleDescription: self.dynamicType.description,
+                severity: configuration.severity,
+                location: Location(file: file, characterOffset: range.location))
+        }
+    }
+
+    private func violationRangesInFile(file: File) -> [NSRange] {
+        let excludingKinds = SyntaxKind.commentAndStringKinds()
+
+        return file.matchPattern(pattern, excludingSyntaxKinds: excludingKinds)
+    }
+
+    public func correctFile(file: File) -> [Correction] {
+        let matches = violationRangesInFile(file)
+        guard !matches.isEmpty else { return [] }
+
+        let regularExpression = regex(pattern)
+        let description = self.dynamicType.description
+        var corrections = [Correction]()
+        var contents = file.contents
+        for range in matches.reverse() {
+            contents = regularExpression.stringByReplacingMatchesInString(contents,
+                                                                          options: [],
+                                                                          range: range,
+                                                                          withTemplate: "$1(")
+            let location = Location(file: file, characterOffset: range.location)
+            corrections.append(Correction(ruleDescription: description, location: location))
+        }
+
+        file.write(contents)
+        return corrections
+    }
+}

SwiftLint.xcodeproj/project.pbxproj

@@ -53,6 +53,7 @@
 		6CCFCF2F1CFEF73E003239EB /* SwiftyTextTable.framework in Embed Frameworks into SwiftLintFramework.framework */ = {isa = PBXBuildFile; fileRef = 3BBF2F9C1C640A0F006CD775 /* SwiftyTextTable.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		6CCFCF301CFEF742003239EB /* Yaml.framework in Embed Frameworks into SwiftLintFramework.framework */ = {isa = PBXBuildFile; fileRef = E89376AC1B8A701E0025708E /* Yaml.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		7250948A1D0859260039B353 /* StatementPositionConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 725094881D0855760039B353 /* StatementPositionConfiguration.swift */; };
+		7C0C2E7A1D2866CB0076435A /* ExplicitInitRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7C0C2E791D2866CB0076435A /* ExplicitInitRule.swift */; };
 		83894F221B0C928A006214E1 /* RulesCommand.swift in Sources */ = {isa = PBXBuildFile; fileRef = 83894F211B0C928A006214E1 /* RulesCommand.swift */; };
 		83D71E281B131ECE000395DE /* RuleDescription.swift in Sources */ = {isa = PBXBuildFile; fileRef = 83D71E261B131EB5000395DE /* RuleDescription.swift */; };
 		85DA81321D6B471000951BC4 /* MarkRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 856651A61D6B395F005E6B29 /* MarkRule.swift */; };
@@ -222,6 +223,7 @@
 		6CB514E81C760C6900FA02C4 /* Structure+SwiftLint.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Structure+SwiftLint.swift"; sourceTree = "<group>"; };
 		6CC4259A1C77046200AEA885 /* SyntaxMap+SwiftLint.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "SyntaxMap+SwiftLint.swift"; sourceTree = "<group>"; };
 		725094881D0855760039B353 /* StatementPositionConfiguration.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = StatementPositionConfiguration.swift; sourceTree = "<group>"; };
+		7C0C2E791D2866CB0076435A /* ExplicitInitRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ExplicitInitRule.swift; sourceTree = "<group>"; };
 		83894F211B0C928A006214E1 /* RulesCommand.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RulesCommand.swift; sourceTree = "<group>"; };
 		83D71E261B131EB5000395DE /* RuleDescription.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RuleDescription.swift; sourceTree = "<group>"; };
 		856651A61D6B395F005E6B29 /* MarkRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MarkRule.swift; sourceTree = "<group>"; };
@@ -604,6 +606,7 @@
 				3B1DF0111C5148140011BCED /* CustomRules.swift */,
 				2E02005E1C54BF680024D09D /* CyclomaticComplexityRule.swift */,
 				E847F0A81BFBBABD00EA9363 /* EmptyCountRule.swift */,
+				7C0C2E791D2866CB0076435A /* ExplicitInitRule.swift */,
 				E88DEA891B0992B300A66CB0 /* FileLengthRule.swift */,
 				E88DEA7F1B09903300A66CB0 /* ForceCastRule.swift */,
 				E816194D1BFBFEAB00946723 /* ForceTryRule.swift */,
@@ -946,6 +949,7 @@
 				B2902A0E1D6681F700BFCCF7 /* PrivateUnitTestConfiguration.swift in Sources */,
 				E88DEA6F1B09843F00A66CB0 /* Location.swift in Sources */,
 				93E0C3CE1D67BD7F007FA25D /* ConditionalReturnsOnNewline.swift in Sources */,
+				7C0C2E7A1D2866CB0076435A /* ExplicitInitRule.swift in Sources */,
 				E88DEA771B098D0C00A66CB0 /* Rule.swift in Sources */,
 				24B4DF0D1D6DFDE90097803B /* RedundantNilCoalesingRule.swift in Sources */,
 				7250948A1D0859260039B353 /* StatementPositionConfiguration.swift in Sources */,

Tests/SwiftLintFramework/RulesTests.swift

@@ -109,6 +109,10 @@ class RulesTests: XCTestCase {
         verifyRule(EmptyCountRule.description)
     }
 
+    func testExplicitInit() {
+        verifyRule(ExplicitInitRule.description)
+    }
+
     func testFileLength() {
         verifyRule(FileLengthRule.description, commentDoesntViolate: false)
     }