Dynamic Inline

Dynamic Inline

dynamic和@inline(__alway)不要同时使用

示例

非触发

class C {
dynamic func f() {}}
class C {
@inline(__always) func f() {}}
class C {
@inline(never) dynamic func f() {}}

触发

class C {
@inline(__always) dynamic ↓func f() {}
}
class C {
@inline(__always) public dynamic ↓func f() {}
}
class C {
@inline(__always) dynamic internal ↓func f() {}
}
class C {
@inline(__always)
dynamic ↓func f() {}
}
class C {
@inline(__always)
dynamic
↓func f() {}
}

补充

深入理解Swift派发机制
Dynamic-Swift
@inline
内联函数

Empty Count

判空首选isEmpty而不是count等于0

示例

非触发

var count = 0
[Int]().isEmpty
[Int]().count > 1
[Int]().count == 1
[Int]().count == 0xff
[Int]().count == 0b01
[Int]().count == 0o07
discount == 0
order.discount == 0

触发

[Int]().↓count == 0
[Int]().↓count > 0
[Int]().↓count != 0
[Int]().↓count == 0x0
[Int]().↓count == 0x00_00
[Int]().↓count == 0b00
[Int]().↓count == 0o00
↓count == 0

Empty Enum Arguments

当枚举和关联类型匹配并没被使用时，可以省略参数。

示例

非触发

switch foo {
    case .bar: break
}
switch foo {
    case .bar(let x): break
}
switch foo {
    case let .bar(x): break
}
switch (foo, bar) {
    case (_, _): break
}
switch foo {
    case "bar".uppercased(): break
}
switch (foo, bar) {
    case (_, _) where !something: break
}
switch foo {
    case (let f as () -> String)?: break
}
switch foo {
    default: break
}

触发

switch foo {
    case .bar↓(_): break
}
switch foo {
    case .bar↓(): break
}
switch foo {
    case .bar↓(_), .bar2↓(_): break
}
switch foo {
    case .bar↓() where method() > 2: break
}
func example(foo: Foo) {
    switch foo {
    case case .bar↓(_):
        break
    }
}

Empty Parameters

首选()->而不是Void->

示例

非触发

let abc: () -> Void = {}
func foo(completion: () -> Void)
func foo(completion: () thows -> Void)
let foo: (ConfigurationTests) -> Void throws -> Void)
let foo: (ConfigurationTests) ->   Void throws -> Void)
let foo: (ConfigurationTests) ->Void throws -> Void)

触发

let abc: ↓(Void) -> Void = {}
func foo(completion: ↓(Void) -> Void)
func foo(completion: ↓(Void) throws -> Void)
let foo: ↓(Void) -> () throws -> Void)

Empty Parentheses with Trailing Closure

使用尾随闭包时，应当避免在方法调用后使用空括号

示例

非触发

[1, 2].map { $0 + 1 }
[1, 2].map({ $0 + 1 })
[1, 2].reduce(0) { $0 + $1 }
[1, 2].map { number in
 number + 1 
}
let isEmpty = [1, 2].isEmpty()
UIView.animateWithDuration(0.3, animations: {
   self.disableInteractionRightView.alpha = 0
}, completion: { _ in
   ()
})

触发

[1, 2].map↓() { $0 + 1 }
[1, 2].map↓( ) { $0 + 1 }
[1, 2].map↓() { number in
 number + 1 
}
[1, 2].map↓(  ) { number in
 number + 1 
}
func foo() -> [Int] {
    return [1, 2].map↓() { $0 + 1 }
}

补充

为什么说是方法调用之后呢？
因为尾随闭包其实是调用方法的一个参数，但是可以写在外边，所以看起来反例里边的括号倒在闭包“之前”而非“之后”了。这里的之后指的是执行顺序而非书写顺序。

Empty String

(判空)首选使用isEmpty而不是比较string和空字符串

示例

非触发

myString.isEmpty
!myString.isEmpy

触发

myString↓ == ""
myString↓ != ""

Empty XCTest Method

避免使用空的测试方法

示例

非触发

class TotoTests: XCTestCase {
    var foobar: Foobar?
    override func setUp() {
        super.setUp()
        foobar = Foobar()
    }
    override func tearDown() {
        foobar = nil
        super.tearDown()
    }
    func testFoo() {
        XCTAssertTrue(foobar?.foo)
    }
    func testBar() {
        // comment...
        XCTAssertFalse(foobar?.bar)
        // comment...
    }
}
class Foobar {
    func setUp() {}
    func tearDown() {}
    func testFoo() {}
}
class TotoTests: XCTestCase {
    func setUp(with object: Foobar) {}
    func tearDown(object: Foobar) {}
    func testFoo(_ foo: Foobar) {}
    func testBar(bar: (String) -> Int) {}
}
class TotoTests: XCTestCase {
    func testFoo() { XCTAssertTrue(foobar?.foo) }
    func testBar() { XCTAssertFalse(foobar?.bar) }
}

触发

class TotoTests: XCTestCase {
    override ↓func setUp() {
    }
    override ↓func tearDown() {
    }
    ↓func testFoo() {
    }
    ↓func testBar() {
    }
    func helperFunction() {
    }
}
class TotoTests: XCTestCase {
    override ↓func setUp() {}
    override ↓func tearDown() {}
    ↓func testFoo() {}
    func helperFunction() {}
}
class TotoTests: XCTestCase {
    override ↓func setUp() {
        // comment...
    }
    override ↓func tearDown() {
        // comment...
        // comment...
    }
    ↓func testFoo() {
        // comment...
        // comment...
        // comment...
    }
    ↓func testBar() {
        /*
         * comment...
         *
         * comment...
         *
         * comment...
         */
    }
    func helperFunction() {
    }
}
class FooTests: XCTestCase {
    override ↓func setUp() {}
}
class BarTests: XCTestCase {
    ↓func testFoo() {}
}

Explicit ACL

所有的声明都应该指定访问控制符。

示例

非触发

internal enum A {}
public final class B {}
private struct C {}
internal enum A {
 internal enum B {}
}
internal final class Foo {}
internal
class Foo {  private let bar = 5 }
internal func a() { let a =  }
private func a() { func innerFunction() { } }
private enum Foo { enum Bar { } }
private struct C { let d = 5 }
internal protocol A {
    func b()
}
internal protocol A {
    var b: Int
}
internal class A { deinit {} }

触发

enum A {}
final class B {}
internal struct C { let d = 5 }
public struct C { let d = 5 }
func a() {}
internal let a = 0
func b() {}

Explicit Enum Raw Value

枚举类型最好指定明确的raw value

示例

非触发

enum Numbers {
 case int(Int)
 case short(Int16)
}
enum Numbers: Int {
 case one = 1
 case two = 2
}
enum Numbers: Double {
 case one = 1.1
 case two = 2.2
}
enum Numbers: String {
 case one = "one"
 case two = "two"
}
protocol Algebra {}
enum Numbers: Algebra {
 case one
}

触发

enum Numbers: Int {
 case one = 10, ↓two, three = 30
}
enum Numbers: NSInteger {
 case ↓one
}
enum Numbers: String {
 case ↓one
 case ↓two
}
enum Numbers: String {
 case ↓one, two = "two"
}
enum Numbers: Decimal {
 case ↓one, ↓two
}

Explicit Init

应当避免直接使用.init()

示例

非触发

import Foundation; 
class C: NSObject { 
    override init() { 
        super.init() 
    }
}
struct S {
 let n: Int 
}; 
extension S {
    init() { 
        self.init(n: 1) 
    } 
}
[1].flatMap(String.init)
[String.self].map { $0.init(1) }
[String.self].map { type in type.init(1) }

触发

[1].flatMap{String↓.init($0)}
[String.self].map { Type in Type↓.init(1) }
func foo() -> [String] {
    return [1].flatMap { String↓.init($0) }
}

Explicit Self

应当使用self.调用自己的变量和方法

示例

非触发

struct A {
    func f1() {}
    func f2() {
        self.f1()
    }
}
struct A {
    let p1: Int
    func f1() {
        _ = self.p1
    }
}

触发

struct A {
    func f1() {}
    func f2() {
        ↓f1()
    }
}
struct A {
    let p1: Int
    func f1() {
        _ = ↓p1
    }
}

补充

持保留意见、我们总是喜欢短小，表达力强的代码。满屏的self并不是我喜欢的。

Explicit Top Level ACL

顶级声明必须明确指定访问权限控制符

示例

非触发

internal enum A {}
public final class B {}
private struct C {}
internal enum A {
 enum B {}
}
internal final class Foo {}
internal
class Foo {}
internal func a() {}

触发

enum A {}
final class B {}
struct C {}
func a() {}
internal let a = 0
func b() {}

Explict Type Interface

属性最好声明类型。

示例

非触发

class Foo {
  var myVar: Int? = 0
}
class Foo {
  let myVar: Int? = 0
}
class Foo {
  static var myVar: Int? = 0
}
class Foo {
  class var myVar: Int? = 0
}

触发

class Foo {
  ↓var myVar = 0
}
class Foo {
  ↓let mylet = 0
}
class Foo {
  ↓static var myStaticVar = 0
}
class Foo {
  ↓class var myClassVar = 0
}
class Foo {
  ↓let myVar = Int(0)
}
class Foo {
  ↓let myVar = Set<Int>(0)
}

Extension Access Modifier

推荐使用扩展访问修饰符。

示例

非触发

extension Foo: SomeProtocol {
   public var bar: Int { return 1 }
}
extension Foo {
   private var bar: Int { return 1 }
   public var baz: Int { return 1 }
}
extension Foo {
   private var bar: Int { return 1 }
   public func baz() {}
}
extension Foo {
   var bar: Int { return 1 }
   var baz: Int { return 1 }
}
public extension Foo {
   var bar: Int { return 1 }
   var baz: Int { return 1 }
}
extension Foo {
   private bar: Int { return 1 }
   private baz: Int { return 1 }
}
extension Foo {
   open bar: Int { return 1 }
   open baz: Int { return 1 }
}

触发

↓extension Foo {
   public var bar: Int { return 1 }
   public var baz: Int { return 1 }
}
↓extension Foo {
   public var bar: Int { return 1 }
   public func baz() {}
}
public extension Foo {
   public ↓func bar() {}
   public ↓func baz() {}
}

补充

正例和反例有相同的地方、没能get到点子上。

Fallthrough

避免使用fallthough

示例

非触发

switch foo {
case .bar, .bar2, .bar3:
    something()
}

触发

switch foo {
case .bar:
    ↓fallthrough
case .bar2:
    something()
}

Fatal Error Message

fatalError方法最好提供message

示例

非触发

func foo() {
  fatalError("Foo")
}
func foo() {
  fatalError(x)
}

触发

func foo() {
  ↓fatalError("")
}
func foo() {
  ↓fatalError()
}

补充

fatalError

File Header

头部描述应当和项目模式一致。SWIFTLINT_CURRENT_FILENAME占位符可以配置必须和禁止选项，这将被真实的文件名替换。

示例

非触发

let foo = "Copyright"
let foo = 2 // Copyright
let foo = 2
 // Copyright

触发

// ↓Copyright
//
// ↓Copyright
//
//  FileHeaderRule.swift
//  SwiftLint
//
//  Created by Marcelo Fabri on 27/11/16.
//  ↓Copyright © 2016 Realm. All rights reserved.
//

补充

我能想到的适用场景就是在文件重命名之后，相应的文件顶部的注释也要一并改掉。

File Line Length

文件不要超过太多行

示例

非触发

print("swiftlint")*400

触发

print("swiftlint")*401

补充

查看源码可知建议不超过400行,个人感觉不好控制,业务复杂可以多一些，业务简单少一些。关键是模块划分合理，层次结构分明。不必过分追求代码行数。仁者见仁，智者见智。

File Name

文件名应当和文件中声明的类型或扩展一致（若存在）

First Where

在集合对象中优先使用.first(where:)而不是.filter{}.first

示例

非触发

kinds.filter(excludingKinds.contains).isEmpty && kinds.first == .identifier
myList.first(where: { $0 % 2 == 0 })
match(pattern: pattern).filter { $0.first == .identifier }
(myList.filter { $0 == 1 }.suffix(2)).first

触发

↓myList.filter { $0 % 2 == 0 }.first
↓myList.filter({ $0 % 2 == 0 }).first
↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).first
↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).first?.something()
↓myList.filter(someFunction).first
↓myList.filter({ $0 % 2 == 0 })
.first
(↓myList.filter { $0 == 1 }).first

For Where

where修饰符优于在for中使用if

示例

非触发

for user in users where user.id == 1 { }
for user in users {
   if let id = user.id { }
}
for user in users {
   if var id = user.id { }
}
for user in users {
   if user.id == 1 { } else { }
}
for user in users {
   if user.id == 1 {
} else if user.id == 2 { }
}
for user in users {
   if user.id == 1 { }
   print(user)
}
for user in users {
   let id = user.id
   if id == 1 { }
}
for user in users {
   if user.id == 1 { }
   return true
}
for user in users {
   if user.id == 1 && user.age > 18 { }
}
for (index, value) in array.enumerated() {
   if case .valueB(_) = value {
       return index
   }
}

触发

for user in users {
   ↓if user.id == 1 { return true }
}

Force Cast

应该避免强制转换

示例

非触发

NSNumber() as? Int

触发

NSNumber() ↓as! Int

Force Try

应该避免强制try

示例

非触发

func a() throws {}; do { try a() } catch {}

触发

func a() throws {}; ↓try! a()

Force Unwrapping

避免强制解包

示例

非触发

if let url = NSURL(string: query)
navigationController?.pushViewController(viewController, animated: true)
let s as! Test
try! canThrowErrors()
let object: Any!
@IBOutlet var constraints: [NSLayoutConstraint]!
setEditing(!editing, animated: true)
navigationController.setNavigationBarHidden(!navigationController.navigationBarHidden, animated: true)
if addedToPlaylist && (!self.selectedFilters.isEmpty || self.searchBar?.text?.isEmpty == false) {}
print("\(xVar)!")
var test = (!bar)
var a: [Int]!
private var myProperty: (Void -> Void)!
func foo(_ options: [AnyHashable: Any]!) {
func foo() -> [Int]!
func foo() -> [AnyHashable: Any]!
func foo() -> [Int]! { return [] }

触发

let url = NSURL(string: query)↓!
navigationController↓!.pushViewController(viewController, animated: true)
let unwrapped = optional↓!
return cell↓!
let url = NSURL(string: "http://www.google.com")↓!
let dict = ["Boooo": "👻"]func bla() -> String { return dict["Boooo"]↓! }
let dict = ["Boooo": "👻"]func bla() -> String { return dict["Boooo"]↓!.contains("B") }
let a = dict["abc"]↓!.contains("B")
dict["abc"]↓!.bar("B")
if dict["a"]↓!!!! {
var foo: [Bool]! = dict["abc"]↓!
context("abc") {
  var foo: [Bool]! = dict["abc"]↓!
}
open var computed: String { return foo.bar↓! }

Function Body Length

函数主体不要过长