SwiftLint/Source/SwiftLintFramework/Rules/OverriddenSuperCallRule.swift

import SourceKittenFramework

public struct OverriddenSuperCallRule: ConfigurationProviderRule, ASTRule, OptInRule {
    public var configuration = OverridenSuperCallConfiguration()

    public init() {}

    public static let description = RuleDescription(
        identifier: "overridden_super_call",
        name: "Overridden methods call super",
        description: "Some overridden methods should always call super",
        kind: .lint,
        nonTriggeringExamples: [
            "class VC: UIViewController {\n" +
                "\toverride func viewWillAppear(_ animated: Bool) {\n" +
                    "\t\tsuper.viewWillAppear(animated)\n" +
                "\t}\n" +
            "}\n",
            "class VC: UIViewController {\n" +
                "\toverride func viewWillAppear(_ animated: Bool) {\n" +
                    "\t\tself.method1()\n" +
                    "\t\tsuper.viewWillAppear(animated)\n" +
                    "\t\tself.method2()\n" +
                "\t}\n" +
            "}\n",
            "class VC: UIViewController {\n" +
                "\toverride func loadView() {\n" +
                "\t}\n" +
            "}\n",
            "class Some {\n" +
                "\tfunc viewWillAppear(_ animated: Bool) {\n" +
                "\t}\n" +
            "}\n",
            "class VC: UIViewController {\n" +
                "\toverride func viewDidLoad() {\n" +
                "\t\tdefer {\n" +
                "\t\t\tsuper.viewDidLoad()\n" +
                "\t\t}\n" +
                "\t}\n" +
            "}\n"
        ],
        triggeringExamples: [
            "class VC: UIViewController {\n" +
                "\toverride func viewWillAppear(_ animated: Bool) {↓\n" +
                    "\t\t//Not calling to super\n" +
                    "\t\tself.method()\n" +
                "\t}\n" +
            "}\n",
            "class VC: UIViewController {\n" +
                "\toverride func viewWillAppear(_ animated: Bool) {↓\n" +
                    "\t\tsuper.viewWillAppear(animated)\n" +
                    "\t\t//Other code\n" +
                    "\t\tsuper.viewWillAppear(animated)\n" +
                "\t}\n" +
            "}\n",
            "class VC: UIViewController {\n" +
                "\toverride func didReceiveMemoryWarning() {↓\n" +
                "\t}\n" +
            "}\n"
        ]
    )

    public func validate(file: File, kind: SwiftDeclarationKind,
                         dictionary: [String: SourceKitRepresentable]) -> [StyleViolation] {
        guard let offset = dictionary.bodyOffset,
            let name = dictionary.name,
            kind == .functionMethodInstance,
            configuration.resolvedMethodNames.contains(name),
            dictionary.enclosedSwiftAttributes.contains(.override)
        else { return [] }

        let callsToSuper = dictionary.extractCallsToSuper(methodName: name)

        if callsToSuper.isEmpty {
            return [StyleViolation(ruleDescription: type(of: self).description,
                                   severity: configuration.severity,
                                   location: Location(file: file, byteOffset: offset),
                                   reason: "Method '\(name)' should call to super function")]
        } else if callsToSuper.count > 1 {
            return [StyleViolation(ruleDescription: type(of: self).description,
                                   severity: configuration.severity,
                                   location: Location(file: file, byteOffset: offset),
                                   reason: "Method '\(name)' should call to super only once")]
        }
        return []
    }
}