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KyNorthstarKyNorthstar
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Merge pull request #25 from RougeWare/bugfix/20-Lazy-property-wrapper-eagerly-evaluated
Bodge guarding against issue #20
2 parents 77d063c + 93bdf54 commit 6981fb1

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-47
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6 files changed

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‎Package.swift‎

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Original file line numberDiff line numberDiff line change
@@ -32,5 +32,7 @@ let package = Package(
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.testTarget(
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name: "LazyContainersTests",
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dependencies: ["LazyContainers"]),
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]
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],
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swiftLanguageVersions: [.v5]
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)

‎Sources/LazyContainers/LazyContainers.swift‎

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@@ -1,9 +1,9 @@
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//
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// LazyContainers.swift
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// Lazy in Swift 5.1
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// Lazy in Swift 5.2
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//
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// Created by Ben Leggiero on 2018-05-04.
6-
// Version 3.1.0 (last edited 2019-08-30)
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// Version 4.0.0 (last edited 2020-08-01)
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// Copyright Ben Leggiero © 2020
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// https://github.com/RougeWare/Swift-Lazy-Patterns/blob/master/LICENSE.txt
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//
@@ -217,6 +217,13 @@ public struct Lazy<Value>: LazyContainer {
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/// Same as `init(initializer:)`, but allows you to use property wrapper andor autoclosure semantics
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///
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/// - Parameter initializer: The closure that will be called the very first time a value is needed
220+
@available(swift, // https://github.com/RougeWare/Swift-Lazy-Patterns/issues/20
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introduced: 5.3,
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message: """
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Due to changes introduced in Swift 5.3, property wrappers can now be passed their initial value lazily, through the language assignment syntax. This initializer requires that behavior to work properly.
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For Swift 5.2.x and earlier, I recommend you don't use `Lazy` as a property wrapper, since Swift 5.2.x property wrappers can't guarantee lazy evaluation.
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This is a real downer for me, but at least it appears to have been a fixable bug, rather than a problem with the core feature itself.
226+
""")
220227
public init(wrappedValue initializer: @autoclosure @escaping Initializer<Value>) {
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self.init(initializer: initializer)
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}

‎Tests/LazyContainersTests/GitHubIssue20Tests.swift‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,39 @@
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//
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// GitHubIssue20Tests.swift
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// LazyContainersTests
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//
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// Created by Gabe Shahbazian on 2020-07-29.
6+
//
7+
8+
import XCTest
9+
@testable import LazyContainers
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11+
12+
13+
#if swift(>=5.3)
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var shouldNotRun = false
15+
16+
class ShouldNotInit {
17+
init() {
18+
shouldNotRun = true
19+
}
20+
}
21+
22+
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24+
/// Guards against issue #20
25+
/// https://github.com/RougeWare/Swift-Lazy-Patterns/issues/20
26+
final class GitHubIssue20Tests: XCTestCase {
27+
28+
@Lazy
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var lazyShouldNotRun = ShouldNotInit()
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31+
func testLazyInitWithPropertyWrapper() {
32+
XCTAssertFalse(shouldNotRun)
33+
}
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35+
static var allTests = [
36+
("testLazyInitWithPropertyWrapper", testLazyInitWithPropertyWrapper)
37+
]
38+
}
39+
#endif

‎Tests/LazyContainersTests/LazyContainersTests.swift‎

Lines changed: 84 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,10 @@
11
//
22
// LazyContainersTests.swift
3+
// LazyContainersTests
34
//
45
// Created by Ben Leggiero on 2019-08-19
5-
// Copyright BH-0-PD © 2019 - https://github.com/BlueHuskyStudios/Licenses/blob/master/Licenses/BH-0-PD.txt
6+
// Copyright Ben Leggiero © 2020
7+
// https://github.com/RougeWare/Swift-Lazy-Patterns/blob/master/LICENSE.txt
68
//
79

810

@@ -12,22 +14,29 @@ import XCTest
1214

1315

1416

15-
var sideEffect: String?
16-
17+
var sideEffectA: String?
1718
func makeLazyA() -> String {
18-
sideEffect = "Side effect A"
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sideEffectA = "Side effect A1"
1920
return "lAzy"
2021
}
2122

23+
var sideEffectB: String?
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func makeLazyB() -> String {
25+
sideEffectB = "Side effect B"
26+
return "Lazy B (this time with side-effects)"
27+
}
28+
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2330

2431
final class LazyContainersTests: XCTestCase {
2532

33+
#if swift(>=5.3)
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@Lazy(initializer: makeLazyA)
27-
var lazyInitWithPropertyWrapper: String
35+
var lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect: String
36+
#endif
2837

2938
var lazyInitTraditionally = Lazy<String>() {
30-
sideEffect = "Side effect B"
39+
sideEffectA = "Side effect A2"
3140
return "lazy B"
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}
3342

@@ -43,7 +52,8 @@ final class LazyContainersTests: XCTestCase {
4352

4453

4554
override func setUp() {
46-
sideEffect = nil
55+
sideEffectA = nil
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sideEffectB = nil
4757
}
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@@ -55,43 +65,60 @@ final class LazyContainersTests: XCTestCase {
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5666
// MARK: - `Lazy`
5767

58-
func testLazyInitWithPropertyWrapper() {
59-
XCTAssertEqual(sideEffect, nil)
60-
XCTAssertFalse(_lazyInitWithPropertyWrapper.isInitialized)
61-
XCTAssertEqual(sideEffect, nil)
62-
XCTAssertEqual("lAzy", lazyInitWithPropertyWrapper)
63-
XCTAssertEqual(sideEffect, "Side effect A")
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XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
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XCTAssertEqual(sideEffect, "Side effect A")
66-
XCTAssertEqual("lAzy", lazyInitWithPropertyWrapper)
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XCTAssertEqual(sideEffect, "Side effect A")
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XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
69-
XCTAssertEqual(sideEffect, "Side effect A")
70-
XCTAssertEqual("lAzy", lazyInitWithPropertyWrapper)
71-
XCTAssertEqual(sideEffect, "Side effect A")
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XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
73-
XCTAssertEqual(sideEffect, "Side effect A")
68+
#if swift(>=5.3)
69+
func testLazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect() {
70+
XCTAssertEqual(sideEffectA, nil)
71+
XCTAssertFalse(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
72+
XCTAssertEqual(sideEffectA, nil)
73+
XCTAssertEqual("lAzy", lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect)
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XCTAssertEqual(sideEffectA, "Side effect A1")
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XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
76+
XCTAssertEqual(sideEffectA, "Side effect A1")
77+
XCTAssertEqual("lAzy", lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect)
78+
XCTAssertEqual(sideEffectA, "Side effect A1")
79+
XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
80+
XCTAssertEqual(sideEffectA, "Side effect A1")
81+
XCTAssertEqual("lAzy", lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect)
82+
XCTAssertEqual(sideEffectA, "Side effect A1")
83+
XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
84+
XCTAssertEqual(sideEffectA, "Side effect A1")
7485

75-
lazyInitWithPropertyWrapper = "MAnual"
86+
lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect = "MAnual"
7687

77-
XCTAssertEqual(sideEffect, "Side effect A")
78-
XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
79-
XCTAssertEqual(sideEffect, "Side effect A")
80-
XCTAssertEqual("MAnual", lazyInitWithPropertyWrapper)
81-
XCTAssertEqual(sideEffect, "Side effect A")
82-
XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
83-
XCTAssertEqual(sideEffect, "Side effect A")
84-
XCTAssertEqual("MAnual", lazyInitWithPropertyWrapper)
85-
XCTAssertEqual(sideEffect, "Side effect A")
86-
XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
87-
XCTAssertEqual(sideEffect, "Side effect A")
88-
XCTAssertEqual("MAnual", lazyInitWithPropertyWrapper)
89-
XCTAssertEqual(sideEffect, "Side effect A")
90-
XCTAssertTrue(_lazyInitWithPropertyWrapper.isInitialized)
91-
XCTAssertEqual(sideEffect, "Side effect A")
88+
XCTAssertEqual(sideEffectA, "Side effect A1")
89+
XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
90+
XCTAssertEqual(sideEffectA, "Side effect A1")
91+
XCTAssertEqual("MAnual", lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect)
92+
XCTAssertEqual(sideEffectA, "Side effect A1")
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XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
94+
XCTAssertEqual(sideEffectA, "Side effect A1")
95+
XCTAssertEqual("MAnual", lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect)
96+
XCTAssertEqual(sideEffectA, "Side effect A1")
97+
XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
98+
XCTAssertEqual(sideEffectA, "Side effect A1")
99+
XCTAssertEqual("MAnual", lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect)
100+
XCTAssertEqual(sideEffectA, "Side effect A1")
101+
XCTAssertTrue(_lazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect.isInitialized)
102+
XCTAssertEqual(sideEffectA, "Side effect A1")
92103
}
93104

94105

106+
func testLazyInitWithPropertyWrapperAndSideEffect() {
107+
108+
struct Test {
109+
@Lazy
110+
var lazyInitWithPropertyWrapperAndSideEffect = makeLazyB()
111+
}
112+
113+
114+
let test = Test()
115+
116+
XCTAssertNil(sideEffectB, "@Lazy eagerly evaluated its initial value")
117+
XCTAssertEqual(test.lazyInitWithPropertyWrapperAndSideEffect, "Lazy B (this time with side-effects)")
118+
}
119+
#endif
120+
121+
95122
func testLazyInitTraditionally() {
96123
XCTAssertFalse(lazyInitTraditionally.isInitialized)
97124
XCTAssertEqual("lazy B", lazyInitTraditionally.wrappedValue)
@@ -249,9 +276,16 @@ final class LazyContainersTests: XCTestCase {
249276
XCTAssertEqual("Manual F", functionalLazyInitTraditionally.wrappedValue)
250277
XCTAssertTrue(functionalLazyInitTraditionally.isInitialized)
251278
}
252-
253-
static var allTests = [
254-
("testLazyInitWithPropertyWrapper", testLazyInitWithPropertyWrapper),
279+
280+
#if swift(>=5.3)
281+
static let testsWhichRequireSwift5_3 = [
282+
("testLazyInitWithPropertyWrapperWithCustomInitializerAndSideEffect", testLazyInitWithPropertyWrapperAndCustomInitializerWithSideEffect),
283+
("testLazyInitWithPropertyWrapperAndSideEffect", testLazyInitWithPropertyWrapperAndSideEffect),
284+
]
285+
#endif
286+
287+
288+
static let testsWhichWorkBeforeSwift5_3 = [
255289
("testLazyInitTraditionally", testLazyInitTraditionally),
256290

257291
("testResettableLazyInitWithPropertyWrapper", testResettableLazyInitWithPropertyWrapper),
@@ -260,4 +294,12 @@ final class LazyContainersTests: XCTestCase {
260294
("testFunctionalLazyInitWithPropertyWrapper", testFunctionalLazyInitWithPropertyWrapper),
261295
("testFunctionalLazyInitTraditionally", testFunctionalLazyInitTraditionally),
262296
]
297+
298+
299+
#if swift(>=5.3)
300+
static let allTests = testsWhichRequireSwift5_3 + testsWhichWorkBeforeSwift5_3
301+
#else
302+
@inline(__always)
303+
static let allTests = testsWhichWorkBeforeSwift5_3
304+
#endif
263305
}

‎Tests/LazyContainersTests/XCTestManifests.swift‎

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Original file line numberDiff line numberDiff line change
@@ -4,6 +4,7 @@ import XCTest
44
public func allTests() -> [XCTestCaseEntry] {
55
return [
66
testCase(LazyContainersTests.allTests),
7+
testCase(GitHubIssue20Tests.allTests),
78
]
89
}
910
#endif

‎Tests/LinuxMain.swift‎

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,9 @@ import XCTest
22

33
import LazyContainersTests
44

5-
var tests = [XCTestCaseEntry]()
6-
tests += LazyContainersTests.allTests()
5+
let tests: [XCTestCaseEntry] = [
6+
LazyContainersTests.allTests,
7+
GitHubIssue20Tests.allTests,
8+
]
9+
710
XCTMain(tests)

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