improve recursiveDeclaredTypeNames()

validating that file names contain the name of a
type or extension declared in the file (if any).

CHANGELOG.md

@@ -101,6 +101,11 @@
 * Make `closure_spacing` a `CorrectableRule`.  
   [J. Cheyo Jimenez](https://github.com/masters3d)
 
+* Add `file_name` opt-in rule validating that file names contain the name of a
+  type or extension declared in the file (if any).  
+  [JP Simard](https://github.com/jpsim)
+  [#1420](https://github.com/realm/SwiftLint/issues/1420)
+
 ##### Bug Fixes
 
 * `emoji` and `checkstyle` reporter output report sorted by file name.  

Source/SwiftLintFramework/Models/MasterRuleList.swift

@@ -99,6 +99,7 @@ public let masterRuleList = RuleList(rules:
     FatalErrorMessageRule.self,
     FileHeaderRule.self,
     FileLengthRule.self,
+    FileNameRule.self,
     FirstWhereRule.self,
     ForceCastRule.self,
     ForceTryRule.self,

Source/SwiftLintFramework/Rules/FileNameRule.swift

@@ -0,0 +1,87 @@
+//
+//  FileNameRule.swift
+//  SwiftLint
+//
+//  Created by JP Simard on 5/24/17.
+//  Copyright © 2017 Realm. All rights reserved.
+//
+
+import Foundation
+import SourceKittenFramework
+
+private let typeAndExtensionKinds = SwiftDeclarationKind.typeKinds() + [.extension, .protocol]
+
+extension Dictionary where Key: ExpressibleByStringLiteral {
+    fileprivate func recursiveDeclaredTypeNames() -> [String] {
+        let subNames = substructure.flatMap { $0.recursiveDeclaredTypeNames() }
+        if let kind = kind.flatMap(SwiftDeclarationKind.init),
+            typeAndExtensionKinds.contains(kind), let name = name {
+            return [name] + subNames
+        }
+        return subNames
+    }
+}
+
+public struct FileNameRule: ConfigurationProviderRule, OptInRule {
+    public var configuration = FileNameConfiguration(severity: .warning, excluded: ["main.swift"])
+
+    public init() {}
+
+    public static let description = RuleDescription(
+        identifier: "file_name",
+        name: "File Name",
+        description: "File name should match a type declared in the file (if any)."
+    )
+
+    public func validate(file: File) -> [StyleViolation] {
+        guard let filePath = file.path,
+            case let fileName = filePath.bridge().lastPathComponent,
+            !configuration.excluded.contains(fileName) else {
+            return []
+        }
+
+        let typeInFileName = fileName.components(separatedBy: CharacterSet(charactersIn: "+.")).first ?? fileName
+
+        let allDeclaredTypeNames = file.structure.dictionary.recursiveDeclaredTypeNames()
+        guard !allDeclaredTypeNames.isEmpty, !allDeclaredTypeNames.contains(typeInFileName) else {
+            return []
+        }
+
+        return [StyleViolation(ruleDescription: type(of: self).description,
+                               severity: configuration.severity.severity,
+                               location: Location(file: filePath, line: 1))]
+    }
+}
+
+public struct FileNameConfiguration: RuleConfiguration, Equatable {
+    public var consoleDescription: String {
+        return "(severity) \(severity.consoleDescription), " +
+            "excluded: \(excluded.sorted())"
+    }
+
+    private(set) public var severity: SeverityConfiguration
+    private(set) public var excluded: Set<String>
+
+    public init(severity: ViolationSeverity, excluded: [String] = []) {
+        self.severity = SeverityConfiguration(severity)
+        self.excluded = Set(excluded)
+    }
+
+    public mutating func apply(configuration: Any) throws {
+        guard let configurationDict = configuration as? [String: Any] else {
+            throw ConfigurationError.unknownConfiguration
+        }
+
+        if let severityConfiguration = configurationDict["severity"] {
+            try severity.apply(configuration: severityConfiguration)
+        }
+        if let excluded = [String].array(of: configurationDict["excluded"]) {
+            self.excluded = Set(excluded)
+        }
+    }
+}
+
+public func == (lhs: FileNameConfiguration, rhs: FileNameConfiguration) -> Bool {
+    return lhs.severity == rhs.severity &&
+        lhs.excluded == rhs.excluded
+}

SwiftLint.xcodeproj/project.pbxproj

@@ -187,6 +187,7 @@
 		E82367E01ED3BD1E0040A88E /* Configuration+Cache.swift in Sources */ = {isa = PBXBuildFile; fileRef = E82367DF1ED3BD1E0040A88E /* Configuration+Cache.swift */; };
 		E832F10B1B17E2F5003F265F /* NSFileManager+SwiftLint.swift in Sources */ = {isa = PBXBuildFile; fileRef = E832F10A1B17E2F5003F265F /* NSFileManager+SwiftLint.swift */; };
 		E832F10D1B17E725003F265F /* IntegrationTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = E832F10C1B17E725003F265F /* IntegrationTests.swift */; };
+		E83530C61ED6328A00FBAF79 /* FileNameRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = E83530C51ED6328A00FBAF79 /* FileNameRule.swift */; };
 		E83A0B351A5D382B0041A60A /* VersionCommand.swift in Sources */ = {isa = PBXBuildFile; fileRef = E83A0B341A5D382B0041A60A /* VersionCommand.swift */; };
 		E847F0A91BFBBABD00EA9363 /* EmptyCountRule.swift in Sources */ = {isa = PBXBuildFile; fileRef = E847F0A81BFBBABD00EA9363 /* EmptyCountRule.swift */; };
 		E84E07471C13F95300F11122 /* AutoCorrectCommand.swift in Sources */ = {isa = PBXBuildFile; fileRef = E84E07461C13F95300F11122 /* AutoCorrectCommand.swift */; };
@@ -482,6 +483,7 @@
 		E82367DF1ED3BD1E0040A88E /* Configuration+Cache.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Configuration+Cache.swift"; sourceTree = "<group>"; };
 		E832F10A1B17E2F5003F265F /* NSFileManager+SwiftLint.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSFileManager+SwiftLint.swift"; sourceTree = "<group>"; };
 		E832F10C1B17E725003F265F /* IntegrationTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = IntegrationTests.swift; sourceTree = "<group>"; };
+		E83530C51ED6328A00FBAF79 /* FileNameRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileNameRule.swift; sourceTree = "<group>"; };
 		E83A0B341A5D382B0041A60A /* VersionCommand.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = VersionCommand.swift; sourceTree = "<group>"; };
 		E847F0A81BFBBABD00EA9363 /* EmptyCountRule.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = EmptyCountRule.swift; sourceTree = "<group>"; };
 		E84E07461C13F95300F11122 /* AutoCorrectCommand.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AutoCorrectCommand.swift; sourceTree = "<group>"; };
@@ -875,6 +877,7 @@
 				C3DE5DAA1E7DF99B00761483 /* FatalErrorMessageRule.swift */,
 				D4C4A34D1DEA877200E0E04C /* FileHeaderRule.swift */,
 				E88DEA891B0992B300A66CB0 /* FileLengthRule.swift */,
+				E83530C51ED6328A00FBAF79 /* FileNameRule.swift */,
 				D42D2B371E09CC0D00CD7A2E /* FirstWhereRule.swift */,
 				E88DEA7F1B09903300A66CB0 /* ForceCastRule.swift */,
 				E816194D1BFBFEAB00946723 /* ForceTryRule.swift */,
@@ -1351,6 +1354,7 @@
 				E80746F61ECB722F00548D31 /* CacheDescriptionProvider.swift in Sources */,
 				094385041D5D4F7C009168CF /* PrivateOutletRule.swift in Sources */,
 				E88DEA6B1B0983FE00A66CB0 /* StyleViolation.swift in Sources */,
+				E83530C61ED6328A00FBAF79 /* FileNameRule.swift in Sources */,
 				3BB47D831C514E8100AE6A10 /* RegexConfiguration.swift in Sources */,
 				D4C889711E385B7B00BAE88D /* RedundantDiscardableLetRule.swift in Sources */,
 				D4D1B9BB1EAC2C910028BE6A /* AccessControlLevel.swift in Sources */,