Merge branch 'release-candidate' into stable

Author: Jeff Verkoeyen

.swift-version

@@ -0,0 +1 @@
+3.0

CHANGELOG.md

@@ -1,3 +1,56 @@
+# 4.0.0
+
+This major release improves the general usage of the observable pattern by removing the
+auto-unsubscription behavior from the Subscription type on deallocation.
+
+```swift
+// Pre-4.0 usage required that you held on to the Subscription instance in order to continue
+// receiving values
+let subscription = observable.subscribe { value in
+  print(value)
+}
+
+// 4.0 allows you to subscribe to streams without holding on to the Subscription instance.
+observable.subscribe { value in
+  print(value)
+}
+```
+
+## Breaking changes
+
+• Subscriptions no longer unsubscribe automatically upon deallocation.
+
+This means that you no longer need to hold on to a Subscription in order to continue receiving
+values from a subscribed stream.
+
+If you were previously depending on this behavior then you must now ensure that you explicitly
+unsubscribe from subscriptions.
+
+## Source changes
+
+* [[breaking] Remove automatic unsubscription from the Subscription object.](https://github.com/material-motion/indefinite-observable-swift/commit/8f5b89cf26bb4e0d26eca254419741278a290ec8) (Jeff Verkoeyen)
+
+## API changes
+
+Auto-generated by running:
+
+    apidiff origin/stable release-candidate swift IndefiniteObservable.xcworkspace IndefiniteObservable
+
+## Subscription
+
+## IndefiniteObservable
+
+*modified* method: `subscribe(observer:)` in `IndefiniteObservable`
+
+| Type of change: | key.attributes |
+|---|---|
+| From: | `(         {         "key.attribute" = "source.decl.attribute.final";     } )` |
+| To: | `(         {         "key.attribute" = "source.decl.attribute.final";     },         {         "key.attribute" = "source.decl.attribute.discardableResult";     } )` |
+
+## Non-source changes
+
+* [Update README with new documentation for subscriptions.](https://github.com/material-motion/indefinite-observable-swift/commit/a492076d65aa9540737ac845fb1380c46cf53a9b) (Jeff Verkoeyen)
+
 # 3.1.0
 
 ## New features

IndefiniteObservable.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.name         = "IndefiniteObservable"
   s.summary      = "IndefiniteObservable is a minimal implementation of Observable with no concept of completion or failure."
-  s.version      = "3.1.0"
+  s.version      = "4.0.0"
   s.authors      = "The Material Motion Authors"
   s.license      = "Apache 2.0"
   s.homepage     = "https://github.com/material-motion/indefinite-observable-swift"

Podfile.lock

@@ -1,8 +1,8 @@
 PODS:
   - CatalogByConvention (2.0.0)
-  - IndefiniteObservable/examples (3.1.0):
+  - IndefiniteObservable/examples (4.0.0):
     - IndefiniteObservable/lib
-  - IndefiniteObservable/lib (3.1.0)
+  - IndefiniteObservable/lib (4.0.0)
 
 DEPENDENCIES:
   - CatalogByConvention
@@ -15,8 +15,8 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   CatalogByConvention: be55c2263132e4f9f59299ac8a528ee8715b3275
-  IndefiniteObservable: 8dd88933eb00b0186cdcc665692beba53da34f44
+  IndefiniteObservable: 0e948393173ea7dc68a9f439530559aa84d96d4c
 
 PODFILE CHECKSUM: 3e4cdba95901e07a289159f0c5a8b830ecb1a5c8
 
-COCOAPODS: 1.1.1
+COCOAPODS: 1.2.0

README.md

@@ -112,20 +112,22 @@ let observable = ValueObservable<<#ValueType#>> { observer in
 
 ## How to subscribe to a stream
 
-Streams are kept in memory by their subscriptions.
-
 ```swift
-let subscription = observable.subscribe { value in
+observable.subscribe { value in
   print(value)
 }
 ```
 
 ## How to unsubscribe from a stream
 
-Unsubscribe from a stream to allow the stream to be released. The stream can be deallocated once all
-of its subscriptions have unsubscribed.
+Unsubscribing will invoke the observable's disconnect method. To unsubscribe, you must retain a
+reference to the subscription instance returned by subscribe.
 
 ```swift
+let subscription = observable.subscribe { value in
+  print(value)
+}
+
 subscription.unsubscribe()
 ```
 

src/IndefiniteObservable.swift

@@ -57,14 +57,18 @@ open class IndefiniteObservable<O: Observer> {
   /**
    Subscribes to the IndefiniteObservable.
 
-   The returned subscription will hold a strong reference to the IndefiniteObservable chain. The
-   reference can be released by calling unsubscribe on the returned subscription. The Subscription
-   is type-erased, making it possible to keep a collection of Subscription objects for as long as
-   you need the associated streams alive.
+   The returned subscription will hold a strong reference to the disconnect chain. The reference can
+   be released by calling unsubscribe on the returned subscription. The Subscription is type-erased,
+   making it possible to keep a collection of Subscription objects for as long as you need the
+   associated streams alive.
+
+   If you do not keep the returned subscription then the disconnect calls will never be invoked for
+   this observer.
 
    - Parameter next: A block that will be executed when new values are sent from upstream.
    - Returns: A subscription.
    */
+  @discardableResult
   public final func subscribe(observer: O) -> Subscription {
     return Subscription(connect(observer))
   }
@@ -82,10 +86,6 @@ public typealias Disconnect = () -> Void
 
 /** A Subscription is returned by IndefiniteObservable.subscribe. */
 public final class Subscription {
-  deinit {
-    unsubscribe()
-  }
-
   public init(_ disconnect: @escaping () -> Void) {
     self.disconnect = disconnect
   }

tests/unit/MemoryLeakTests.swift

@@ -63,7 +63,7 @@ class MemoryLeakTests: XCTestCase {
     weak var weakObservable = observable
 
     autoreleasepool {
-      let _ = observable!.subscribe {
+      observable!.subscribe {
         let _ = $0
       }
       // Remove our only strong reference.
@@ -83,7 +83,7 @@ class MemoryLeakTests: XCTestCase {
     weak var weakObservable = observable
 
     autoreleasepool {
-      let _ = observable!.map { value in
+      observable!.map { value in
         return value * value
         }.subscribe {
           let _ = $0
@@ -97,7 +97,7 @@ class MemoryLeakTests: XCTestCase {
     XCTAssertNil(weakObservable)
   }
 
-  func testUnsubscribedObservableWithOperatorIsDeallocated() {
+  func testObservableWithOperatorIsDeallocated() {
     weak var weakObservable: ValueObservable<CGFloat>?
     autoreleasepool {
       let observable: ValueObservable<CGFloat>? = ValueObservable<CGFloat> { observer in
@@ -106,13 +106,11 @@ class MemoryLeakTests: XCTestCase {
       }
       weakObservable = observable
 
-      let subscription = observable!.map { value in
+      observable!.map { value in
         return value * value
-        }.subscribe {
-          let _ = $0
-        }
-      // Remove our only strong reference.
-      subscription.unsubscribe()
+      }.subscribe {
+        let _ = $0
+      }
     }
 
     // If this fails it means there's a retain cycle. Place a breakpoint here and use the Debug
@@ -122,7 +120,6 @@ class MemoryLeakTests: XCTestCase {
 
   func testSubscriptionDoesNotKeepObservableInMemory() {
     weak var weakObservable: ValueObservable<Int>?
-    var subscription: Subscription?
 
     autoreleasepool {
       let value = 10
@@ -132,11 +129,34 @@ class MemoryLeakTests: XCTestCase {
       }
       weakObservable = observable
 
-      subscription = observable.subscribe { _ in }
+      observable.subscribe { _ in }
     }
 
     XCTAssertNil(weakObservable)
+  }
+
+  func testSubscriptionDoesNotKeepObserverInMemory() {
+    weak var weakObserver: ValueObserver<Int>?
+
+    var didDisconnect = false
+    var didSetObserver = false
+
+    autoreleasepool {
+      let value = 10
+      let observable = ValueObservable<Int> { observer in
+        weakObserver = observer
+        didSetObserver = true
+        observer.next(value)
+        return {
+          didDisconnect = true
+        }
+      }
+
+      observable.subscribe { _ in }
+    }
 
-    subscription?.unsubscribe()
+    XCTAssertNil(weakObserver)
+    XCTAssertTrue(didSetObserver)
+    XCTAssertFalse(didDisconnect)
   }
 }