Added fileprivateRule

CHANGELOG.md

@@ -13,6 +13,11 @@
 * Match `(Void)` as return type in the `void_return` rule.  
   [Anders Hasselqvist](https://github.com/nevil)
 
+* Added `fileprivateRule` to check for top-level usages of `fileprivate` and recommend `private` instead. This is inline with SE-0169's goal "for `fileprivate` to be used rarely". There is a also an "strict" option that will mark every `fileprivate` as a violation.  
+  [Jose Cheyo Jimenez](https://github.com/masters3d)
+  [#1469](https://github.com/realm/SwiftLint/issues/1469)
+  [#1058](https://github.com/realm/SwiftLint/issues/1058)
+
 * Add `multiline_parameters` opt-in rule that warns to either keep
   all the parameters of a method or function on the same line,
   or one per line.  

Source/SwiftLintFramework/Models/MasterRuleList.swift

@@ -35,6 +35,7 @@ public let masterRuleList = RuleList(rules: [
     FatalErrorMessageRule.self,
     FileHeaderRule.self,
     FileLengthRule.self,
+    FileprivateRule.self,
     FirstWhereRule.self,
     ForWhereRule.self,
     ForceCastRule.self,

Source/SwiftLintFramework/Rules/FileprivateRule.swift

@@ -0,0 +1,53 @@
+//
+//  FileprivateRule.swift
+//  SwiftLint
+//
+//  Created by Jose Cheyo Jimenez on 05/02/17.
+//  Copyright © 2017 Realm. All rights reserved.
+//
+
+import Foundation
+import SourceKittenFramework
+
+public struct FileprivateRule: Rule, ConfigurationProviderRule {
+    public var configuration = FileprivateConfiguration(strict: false)
+
+    public init() {}
+
+    public static let description = FileprivateConfiguration.fileprivateLimited
+
+    public func validate(file: File) -> [StyleViolation] {
+        if !configuration.strict {
+            let toplevel = file.structure.dictionary.substructure.flatMap({ $0.offset })
+            let syntaxTokens = file.syntaxMap.tokens
+            let violationOffsets = toplevel.flatMap { (offSet) -> Int? in
+                let parts = syntaxTokens.partitioned { offSet <= $0.offset }
+                guard let lastKind = parts.first.last,
+                    lastKind.type == SyntaxKind.attributeBuiltin.rawValue,
+                    // Cut the amount of name-look-ups by first checking the char count
+                    lastKind.length == "fileprivate".bridge().length,
+                    // Get the actual name of the attibute
+                    let aclName = file.contents.bridge()
+                            .substringWithByteRange(start:lastKind.offset, length: lastKind.length),
+                    // fileprivate(set) is not possible at toplevel
+                    aclName == "fileprivate"
+                    else { return nil }
+                return offSet
+            }
+            return violationOffsets.map({ StyleViolation(
+                ruleDescription: FileprivateConfiguration.fileprivateLimited,
+                location: Location(file: file, byteOffset: $0))
+            })
+
+        } else { // Mark all fileprivate occurences as a violation
+            let fileprivates = file.match(pattern: "fileprivate", with: [.attributeBuiltin]).flatMap({
+                file.contents.bridge().NSRangeToByteRange(start: $0.location, length: $0.length)
+            }).map({ $0.location })
+            return fileprivates.map({ StyleViolation(
+                ruleDescription: FileprivateConfiguration.fileprivateDisallowed,
+                location: Location(file: file, byteOffset: $0))
+            })
+        }
+
+    }
+}

Source/SwiftLintFramework/Rules/IdentifierNameRule.swift

@@ -115,7 +115,7 @@ public struct IdentifierNameRule: ASTRule, ConfigurationProviderRule {
     }
 }
 
-fileprivate extension String {
+private extension String {
     var isViolatingCase: Bool {
         let secondIndex = characters.index(after: startIndex)
         let firstCharacter = substring(to: secondIndex)

Source/SwiftLintFramework/Rules/RuleConfigurations/FileprivateConfiguration.swift

@@ -0,0 +1,90 @@
+//
+//  FileprivateConfiguration.swift
+//  SwiftLint
+//
+//  Created by Jose Cheyo Jimenez on 05/02/17.
+//  Copyright © 2017 Realm. All rights reserved.
+//
+
+public struct FileprivateConfiguration: RuleConfiguration, Equatable {
+    private(set) var severityConfiguration = SeverityConfiguration(.warning)
+    private(set) var strict: Bool
+
+    public var consoleDescription: String {
+        return severityConfiguration.consoleDescription + ", strict: \(strict)"
+    }
+
+    public init(strict: Bool) {
+        self.strict = strict
+    }
+
+    public mutating func apply(configuration: Any) throws {
+        guard let configuration = configuration as? [String: Any] else {
+            throw ConfigurationError.unknownConfiguration
+        }
+
+        if let strict = configuration["strict"] as? Bool {
+            self.strict = strict
+        }
+
+        if let severityString = configuration["severity"] as? String {
+            try severityConfiguration.apply(configuration: severityString)
+        }
+    }
+
+    public static let fileprivateLimited = RuleDescription(
+        identifier: "fileprivate",
+        name: "Limit Fileprivate",
+        description: "Prefer private over fileprivate for top-level declarations",
+        nonTriggeringExamples: [
+            "extension String {}",
+            "private extension String {}",
+            "public \n enum MyEnum {}",
+            "open extension \n String {}",
+            "internal extension String {}",
+            "extension String {\nfileprivate func Something(){}\n}",
+            "class MyClass {\nfileprivate let myInt = 4\n}",
+            "class MyClass {\nfileprivate(set) var myInt = 4\n}",
+            "struct Outter {\nstruct Inter {\nfileprivate struct Inner {}\n}\n}"
+            ],
+        triggeringExamples: [
+            "fileprivate enum MyEnum {}",
+            "fileprivate extension String {}",
+            "fileprivate \n extension String {}",
+            "fileprivate extension \n String {}",
+            "fileprivate class MyClass {\nfileprivate(set) var myInt = 4\n}",
+            "fileprivate extension String {}"
+            ]
+    )
+
+    public static let fileprivateDisallowed = RuleDescription(
+        identifier: "fileprivate",
+        name: "Fileprivate Disallowed",
+        description: "Fileprivate should be rare. Consider refactoring",
+        nonTriggeringExamples: [
+            "extension String {}",
+            "private extension String {}",
+            "public \n extension String {}",
+            "open extension \n String {}",
+            "internal extension String {}",
+            ""
+            ],
+        triggeringExamples: [
+            "fileprivate extension String {}",
+            "fileprivate extension String {}",
+            "fileprivate \n extension String {}",
+            "fileprivate extension \n String {}",
+            "fileprivate extension String {}",
+            "extension String {\nfileprivate func Something(){}\n}",
+            "class MyClass {\nfileprivate let myInt = 4\n}",
+            "class MyClass {\nfileprivate(set) var myInt = 4\n}",
+            "struct Outter {\nstruct Inter {\nfileprivate struct Inner {}\n}\n}"
+            ]
+    )
+
+    public static func == (lhs: FileprivateConfiguration,
+                           rhs: FileprivateConfiguration) -> Bool {
+        return lhs.strict == rhs.strict &&
+            lhs.severityConfiguration == rhs.severityConfiguration
+    }
+}

SwiftLint.xcodeproj/project.pbxproj

@@ -17,6 +17,8 @@
 		094385011D5D2894009168CF /* WeakDelegateRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 094384FF1D5D2382009168CF /* WeakDelegateRule.swift */; };
 		094385041D5D4F7C009168CF /* PrivateOutletRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 094385021D5D4F78009168CF /* PrivateOutletRule.swift */; };
 		1E18574B1EADBA51004F89F7 /* NoExtensionAccessModifier.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1E18574A1EADBA51004F89F7 /* NoExtensionAccessModifier.swift */; };
+		1E3C2D711EE36C6F00C8386D /* FileprivateRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1E3C2D701EE36C6F00C8386D /* FileprivateRule.swift */; };
+		1E3C2D731EE36D3500C8386D /* FileprivateConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1E3C2D721EE36D3500C8386D /* FileprivateConfiguration.swift */; };
 		1E82D5591D7775C7009553D7 /* ClosureSpacingRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1E82D5581D7775C7009553D7 /* ClosureSpacingRule.swift */; };
 		1EC163521D5992D900DD2928 /* VerticalWhitespaceRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1EC163511D5992D900DD2928 /* VerticalWhitespaceRule.swift */; };
 		1EF115921EB2AD5900E30140 /* ExplicitTopLevelACLRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1EF115911EB2AD5900E30140 /* ExplicitTopLevelACLRule.swift */; };
@@ -301,6 +303,8 @@
 		094384FF1D5D2382009168CF /* WeakDelegateRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = WeakDelegateRule.swift; sourceTree = "<group>"; };
 		094385021D5D4F78009168CF /* PrivateOutletRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PrivateOutletRule.swift; sourceTree = "<group>"; };
 		1E18574A1EADBA51004F89F7 /* NoExtensionAccessModifier.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NoExtensionAccessModifier.swift; sourceTree = "<group>"; };
+		1E3C2D701EE36C6F00C8386D /* FileprivateRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileprivateRule.swift; sourceTree = "<group>"; };
+		1E3C2D721EE36D3500C8386D /* FileprivateConfiguration.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileprivateConfiguration.swift; sourceTree = "<group>"; };
 		1E82D5581D7775C7009553D7 /* ClosureSpacingRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ClosureSpacingRule.swift; sourceTree = "<group>"; };
 		1EC163511D5992D900DD2928 /* VerticalWhitespaceRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = VerticalWhitespaceRule.swift; sourceTree = "<group>"; };
 		1EF115911EB2AD5900E30140 /* ExplicitTopLevelACLRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ExplicitTopLevelACLRule.swift; sourceTree = "<group>"; };
@@ -604,6 +608,7 @@
 				D43B04671E07228D004016AF /* ColonConfiguration.swift */,
 				67EB4DF81E4CC101004E9ACD /* CyclomaticComplexityConfiguration.swift */,
 				D4C4A3511DEFBBB700E0E04C /* FileHeaderConfiguration.swift */,
+				1E3C2D721EE36D3500C8386D /* FileprivateConfiguration.swift */,
 				47ACC8971E7DC74E0088EEB2 /* ImplicitlyUnwrappedOptionalConfiguration.swift */,
 				3B034B6C1E0BE544005D49A9 /* LineLengthConfiguration.swift */,
 				3BCC04D01C4F56D3006073C3 /* NameConfiguration.swift */,
@@ -894,6 +899,7 @@
 				C3DE5DAA1E7DF99B00761483 /* FatalErrorMessageRule.swift */,
 				D4C4A34D1DEA877200E0E04C /* FileHeaderRule.swift */,
 				E88DEA891B0992B300A66CB0 /* FileLengthRule.swift */,
+				1E3C2D701EE36C6F00C8386D /* FileprivateRule.swift */,
 				D42D2B371E09CC0D00CD7A2E /* FirstWhereRule.swift */,
 				E88DEA7F1B09903300A66CB0 /* ForceCastRule.swift */,
 				E816194D1BFBFEAB00946723 /* ForceTryRule.swift */,
@@ -1317,6 +1323,7 @@
 				D4B0226F1E0C75F9007E5297 /* VerticalParameterAlignmentRule.swift in Sources */,
 				E8BDE3FF1EDF91B6002EC12F /* RuleList.swift in Sources */,
 				D44254271DB9C15C00492EA4 /* SyntacticSugarRule.swift in Sources */,
+				1E3C2D731EE36D3500C8386D /* FileprivateConfiguration.swift in Sources */,
 				006204DC1E1E492F00FFFBE1 /* VerticalWhitespaceConfiguration.swift in Sources */,
 				E88198441BEA93D200333A11 /* ColonRule.swift in Sources */,
 				E809EDA11B8A71DF00399043 /* Configuration.swift in Sources */,
@@ -1385,6 +1392,7 @@
 				1EF115921EB2AD5900E30140 /* ExplicitTopLevelACLRule.swift in Sources */,
 				D41E7E0B1DF9DABB0065259A /* RedundantStringEnumValueRule.swift in Sources */,
 				E88DEA711B09847500A66CB0 /* ViolationSeverity.swift in Sources */,
+				1E3C2D711EE36C6F00C8386D /* FileprivateRule.swift in Sources */,
 				B2902A0C1D66815600BFCCF7 /* PrivateUnitTestRule.swift in Sources */,
 				D47A51101DB2DD4800A4CC21 /* AttributesRule.swift in Sources */,
 				CE8178ED1EAC039D0063186E /* UnusedOptionalBindingConfiguration.swift in Sources */,

Tests/LinuxMain.swift

@@ -322,6 +322,8 @@ extension RulesTests {
         ("testExtensionAccessModifier", testExtensionAccessModifier),
         ("testFatalErrorMessage", testFatalErrorMessage),
         ("testFileLength", testFileLength),
+        ("testFileprivateRule", testFileprivateRule),
+        ("testFileprivateRuleWithConfig", testFileprivateRuleWithConfig),
         ("testFirstWhere", testFirstWhere),
         ("testForceCast", testForceCast),
         ("testForceTry", testForceTry),

Tests/SwiftLintFrameworkTests/ConfigurationTests.swift

@@ -260,7 +260,7 @@ class ConfigurationTests: XCTestCase {
 
 // MARK: - ProjectMock Paths
 
-fileprivate extension String {
+private extension String {
     func stringByAppendingPathComponent(_ pathComponent: String) -> String {
         return bridge().appendingPathComponent(pathComponent)
     }
@@ -276,7 +276,7 @@ extension XCTestCase {
     }
 }
 
-fileprivate extension XCTestCase {
+private extension XCTestCase {
 
     var projectMockPathLevel0: String {
         return bundlePath.stringByAppendingPathComponent("ProjectMock")

Tests/SwiftLintFrameworkTests/LinterCacheTests.swift

@@ -10,7 +10,7 @@ import Foundation
 @testable import SwiftLintFramework
 import XCTest
 
-fileprivate struct CacheTestHelper {
+private struct CacheTestHelper {
     fileprivate let configuration: Configuration
 
     private let ruleList: RuleList
@@ -60,7 +60,7 @@ fileprivate struct CacheTestHelper {
     }
 }
 
-fileprivate class TestFileManager: LintableFileManager {
+private class TestFileManager: LintableFileManager {
     fileprivate func filesToLint(inPath: String, rootDirectory: String? = nil) -> [String] {
         return []
     }

Tests/SwiftLintFrameworkTests/RulesTests.swift

@@ -101,6 +101,15 @@ class RulesTests: XCTestCase {
                    testMultiByteOffsets: false)
     }
 
+    func testFileprivateRule() {
+        verifyRule(FileprivateConfiguration.fileprivateLimited)
+    }
+
+    func testFileprivateRuleWithConfig() {
+        verifyRule(FileprivateConfiguration.fileprivateDisallowed,
+                   ruleConfiguration: ["strict": true])
+    }
+
     func testFirstWhere() {
         verifyRule(FirstWhereRule.description)
     }