Restore original cancellation logic (#245)

* Revert "Run swift-format"

This reverts commit 6a5b8f2.

* Revert "Fix iOS 14 Cancellation Crash (#244)"

This reverts commit 2bf1be6.

* Xcode 12 CI

* Update ci.yml

Author: stephencelis

Sources/ComposableArchitecture/Effects/Cancellation.swift

@@ -27,61 +27,35 @@ extension Effect {
   ///     canceled before starting this new one.
   /// - Returns: A new effect that is capable of being canceled by an identifier.
   public func cancellable(id: AnyHashable, cancelInFlight: Bool = false) -> Effect {
-    // NB: This check intends to work around bugs over different versions of Combine
-    #if swift(>=5.3) && !os(macOS)
-      let effect = Deferred<
-        Publishers.PrefixUntilOutput<Publishers.HandleEvents<Self>, PassthroughSubject<Void, Never>>
-      > {
-        let subject = PassthroughSubject<Void, Never>()
-        lock.sync { subjects[id, default: []].append(subject) }
-        let cleanup = {
-          lock.sync {
-            subjects[id]?.removeAll(where: { $0 === subject })
-            if subjects[id]?.isEmpty == true {
-              subjects[id] = nil
-            }
-          }
-        }
-        return
-          self
-          .handleEvents(
-            receiveCompletion: { _ in cleanup() },
-            receiveCancel: cleanup
-          )
-          .prefix(untilOutputFrom: subject)
-      }
-      .eraseToEffect()
-    #else
-      let effect = Deferred { () -> Publishers.HandleEvents<PassthroughSubject<Output, Failure>> in
-        cancellablesLock.lock()
-        defer { cancellablesLock.unlock() }
+    let effect = Deferred { () -> Publishers.HandleEvents<PassthroughSubject<Output, Failure>> in
+      cancellablesLock.lock()
+      defer { cancellablesLock.unlock() }
 
-        let subject = PassthroughSubject<Output, Failure>()
-        let cancellable = self.subscribe(subject)
+      let subject = PassthroughSubject<Output, Failure>()
+      let cancellable = self.subscribe(subject)
 
-        var cancellationCancellable: AnyCancellable!
-        cancellationCancellable = AnyCancellable {
-          cancellablesLock.sync {
-            subject.send(completion: .finished)
-            cancellable.cancel()
-            cancellationCancellables[id]?.remove(cancellationCancellable)
-            if cancellationCancellables[id]?.isEmpty == .some(true) {
-              cancellationCancellables[id] = nil
-            }
+      var cancellationCancellable: AnyCancellable!
+      cancellationCancellable = AnyCancellable {
+        cancellablesLock.sync {
+          subject.send(completion: .finished)
+          cancellable.cancel()
+          cancellationCancellables[id]?.remove(cancellationCancellable)
+          if cancellationCancellables[id]?.isEmpty == .some(true) {
+            cancellationCancellables[id] = nil
           }
         }
+      }
 
-        cancellationCancellables[id, default: []].insert(
-          cancellationCancellable
-        )
+      cancellationCancellables[id, default: []].insert(
+        cancellationCancellable
+      )
 
-        return subject.handleEvents(
-          receiveCompletion: { _ in cancellationCancellable.cancel() },
-          receiveCancel: cancellationCancellable.cancel
-        )
-      }
-      .eraseToEffect()
-    #endif
+      return subject.handleEvents(
+        receiveCompletion: { _ in cancellationCancellable.cancel() },
+        receiveCancel: cancellationCancellable.cancel
+      )
+    }
+    .eraseToEffect()
 
     return cancelInFlight ? .concatenate(.cancel(id: id), effect) : effect
   }
@@ -92,26 +66,13 @@ extension Effect {
   /// - Returns: A new effect that will cancel any currently in-flight effect with the given
   ///   identifier.
   public static func cancel(id: AnyHashable) -> Effect {
-    #if swift(>=5.3) && !os(macOS)
-      return .fireAndForget {
-        lock.sync {
-          subjects[id]?.forEach { $0.send(()) }
-        }
-      }
-    #else
-      return .fireAndForget {
-        cancellablesLock.sync {
-          cancellationCancellables[id]?.forEach { $0.cancel() }
-        }
+    return .fireAndForget {
+      cancellablesLock.sync {
+        cancellationCancellables[id]?.forEach { $0.cancel() }
       }
-    #endif
+    }
   }
 }
 
-#if swift(>=5.3) && !os(macOS)
-  var subjects: [AnyHashable: [PassthroughSubject<Void, Never>]] = [:]
-  let lock = NSRecursiveLock()
-#else
-  var cancellationCancellables: [AnyHashable: Set<AnyCancellable>] = [:]
-  let cancellablesLock = NSRecursiveLock()
-#endif
+var cancellationCancellables: [AnyHashable: Set<AnyCancellable>] = [:]
+let cancellablesLock = NSRecursiveLock()

Tests/ComposableArchitectureTests/EffectCancellationTests.swift

@@ -116,11 +116,7 @@ final class EffectCancellationTests: XCTestCase {
       .sink(receiveValue: { _ in })
       .store(in: &self.cancellables)
 
-    #if swift(>=5.3) && !os(macOS)
-      XCTAssertTrue(subjects.isEmpty)
-    #else
-      XCTAssertTrue(cancellationCancellables.isEmpty)
-    #endif
+    XCTAssertEqual([:], cancellationCancellables)
   }
 
   func testCancellablesCleanUp_OnCancel() {
@@ -136,11 +132,7 @@ final class EffectCancellationTests: XCTestCase {
       .sink(receiveValue: { _ in })
       .store(in: &self.cancellables)
 
-    #if swift(>=5.3) && !os(macOS)
-      XCTAssertTrue(subjects.isEmpty)
-    #else
-      XCTAssertTrue(cancellationCancellables.isEmpty)
-    #endif
+    XCTAssertEqual([:], cancellationCancellables)
   }
 
   func testDoubleCancellation() {
@@ -230,11 +222,7 @@ final class EffectCancellationTests: XCTestCase {
       .store(in: &self.cancellables)
     self.wait(for: [expectation], timeout: 999)
 
-    #if swift(>=5.3) && !os(macOS)
-      XCTAssertTrue(subjects.isEmpty)
-    #else
-      XCTAssertTrue(cancellationCancellables.isEmpty)
-    #endif
+    XCTAssertTrue(cancellationCancellables.isEmpty)
   }
 
   func testNestedCancels() {
@@ -252,11 +240,7 @@ final class EffectCancellationTests: XCTestCase {
 
     cancellables.removeAll()
 
-    #if swift(>=5.3) && !os(macOS)
-      XCTAssertTrue(subjects.isEmpty)
-    #else
-      XCTAssertTrue(cancellationCancellables.isEmpty)
-    #endif
+    XCTAssertEqual([:], cancellationCancellables)
   }
 
   func testSharedId() {