Deprecates `Variable` implementing `ObservableType` in favor of `asObservable()`, and changes behavior so it completes the sequence once it is deallocated.

Documentation/GettingStarted.md

@@ -700,7 +700,7 @@ This isn't something that should be practiced often, and is a bad code smell, bu
 
   let kittens = Variable(firstKitten) // again back in Rx monad
 
-  kittens
+  kittens.asObservable()
     .map { kitten in
       return kitten.purr()
     }
@@ -873,12 +873,14 @@ Variable wraps a [`Subject`](http://reactivex.io/documentation/subject.html). Mo
 
 It will also broadcast it's current value immediately on subscription.
 
+After variable is deallocated, it will complete the observable sequence returned from `.asObservable()`.
+
 ```swift
 let variable = Variable(0)
 
 print("Before first subscription ---")
 
-variable
+variable.asObservable()
     .subscribeNext { n in
         print("First \(n)")
     }

Rx.playground/Pages/Combining_Observables.xcplaygroundpage/Contents.swift

@@ -255,9 +255,10 @@ example("switchLatest") {
     let var2 = Variable(200)
 
     // var3 is like an Observable<Observable<Int>>
-    let var3 = Variable(var1)
+    let var3 = Variable(var1.asObservable())
 
     let d = var3
+        .asObservable()
         .switchLatest()
         .subscribe {
             print($0)
@@ -268,7 +269,7 @@ example("switchLatest") {
     var1.value = 3
     var1.value = 4
 
-    var3.value = var2
+    var3.value = var2.asObservable()
 
     var2.value = 201
 

Rx.playground/Pages/Subjects.xcplaygroundpage/Contents.swift

@@ -93,10 +93,10 @@ example("BehaviorSubject") {
 example("Variable") {
     let disposeBag = DisposeBag()
     let variable = Variable("z")
-    writeSequenceToConsole("1", sequence: variable).addDisposableTo(disposeBag)
+    writeSequenceToConsole("1", sequence: variable.asObservable()).addDisposableTo(disposeBag)
     variable.value = "a"
     variable.value = "b"
-    writeSequenceToConsole("2", sequence: variable).addDisposableTo(disposeBag)
+    writeSequenceToConsole("2", sequence: variable.asObservable()).addDisposableTo(disposeBag)
     variable.value = "c"
     variable.value = "d"
 }

RxCocoa/Common/CocoaUnits/Driver/Variable+Driver.swift

@@ -19,7 +19,7 @@ extension Variable {
      */
     @warn_unused_result(message="http://git.io/rxs.uo")
     public func asDriver() -> Driver<E> {
-        let source = self
+        let source = self.asObservable()
             .observeOn(driverObserveOnScheduler)
         return Driver(source)
     }

RxExample/RxExample/Examples/PartialUpdates/PartialUpdatesViewController.swift

@@ -45,39 +45,6 @@ class PartialUpdatesViewController : ViewController {
 
     var sections = Variable([NumberSection]())
 
-    func skinTableViewDataSource(dataSource: RxTableViewSectionedDataSource<NumberSection>) {
-        dataSource.cellFactory = { (tv, ip, i) in
-            let cell = tv.dequeueReusableCellWithIdentifier("Cell")
-                ?? UITableViewCell(style:.Default, reuseIdentifier: "Cell")
-
-            cell.textLabel!.text = "\(i)"
-
-            return cell
-        }
-
-        dataSource.titleForHeaderInSection = { [unowned dataSource] (section: Int) -> String in
-            return dataSource.sectionAtIndex(section).model
-        }
-    }
-
-    func skinCollectionViewDataSource(dataSource: RxCollectionViewSectionedDataSource<NumberSection>) {
-        dataSource.cellFactory = { (cv, ip, i) in
-            let cell = cv.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: ip) as! NumberCell
-
-            cell.value!.text = "\(i)"
-
-            return cell
-        }
-
-        dataSource.supplementaryViewFactory = { [unowned dataSource] (cv, kind, ip) in
-            let section = cv.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: "Section", forIndexPath: ip) as! NumberSectionView
-
-            section.value!.text = "\(dataSource.sectionAtIndex(ip.section).model)"
-
-            return section
-        }
-    }
-
     override func viewDidLoad() {
         super.viewDidLoad()
 
@@ -162,6 +129,39 @@ class PartialUpdatesViewController : ViewController {
             .addDisposableTo(disposeBag)
     }
 
+    func skinTableViewDataSource(dataSource: RxTableViewSectionedDataSource<NumberSection>) {
+        dataSource.cellFactory = { (tv, ip, i) in
+            let cell = tv.dequeueReusableCellWithIdentifier("Cell")
+                ?? UITableViewCell(style:.Default, reuseIdentifier: "Cell")
+
+            cell.textLabel!.text = "\(i)"
+
+            return cell
+        }
+
+        dataSource.titleForHeaderInSection = { [unowned dataSource] (section: Int) -> String in
+            return dataSource.sectionAtIndex(section).model
+        }
+    }
+
+    func skinCollectionViewDataSource(dataSource: RxCollectionViewSectionedDataSource<NumberSection>) {
+        dataSource.cellFactory = { (cv, ip, i) in
+            let cell = cv.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: ip) as! NumberCell
+
+            cell.value!.text = "\(i)"
+
+            return cell
+        }
+
+        dataSource.supplementaryViewFactory = { [unowned dataSource] (cv, kind, ip) in
+            let section = cv.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: "Section", forIndexPath: ip) as! NumberSectionView
+
+            section.value!.text = "\(dataSource.sectionAtIndex(ip.section).model)"
+
+            return section
+        }
+    }
+
     override func viewWillDisappear(animated: Bool) {
         self.timer?.invalidate()
     }

RxExample/RxExample/Operators.swift

@@ -18,7 +18,7 @@ infix operator <-> {
 }
 
 func <-> <T>(property: ControlProperty<T>, variable: Variable<T>) -> Disposable {
-    let bindToUIDisposable = variable
+    let bindToUIDisposable = variable.asObservable()
         .bindTo(property)
     let bindToVariable = property
         .subscribe(onNext: { n in

RxExample/RxExample/Services/ActivityIndicator.swift

@@ -44,7 +44,7 @@ class ActivityIndicator : DriverConvertibleType {
     private let _loading: Driver<Bool>
 
     init() {
-        _loading = _variable
+        _loading = _variable.asObservable()
             .map { $0 > 0 }
             .distinctUntilChanged()
             .asDriver { (error: ErrorType) -> Driver<Bool> in

RxSwift/Subjects/Variable.swift

@@ -11,9 +11,13 @@ import Foundation
 /**
 Variable is a wrapper for `BehaviorSubject`.
 
-Unlike `BehaviorSubject` it can't terminate with error.
+Unlike `BehaviorSubject` it can't terminate with error, and when variable is deallocated
+ it will complete it's observable sequence (`asObservable`).
 */
-public class Variable<Element> : ObservableType {
+@available(*, deprecated=2.0.0, message="Variable will remain in the 2.0.0 API, but just use `variable.asObservable()` because it won't be `ObservableType` (no way to warn about deprecated interface implementation). Just do, `variable.asObservable().map { _ in ...}` and ignore this warning.")
+public class Variable<Element>
+    :  ObservableType { // << -- this part and subscribe method will be deprecated
+
     public typealias E = Element
     
     private let _subject: BehaviorSubject<Element>
@@ -73,4 +77,8 @@ public class Variable<Element> : ObservableType {
     public func asObservable() -> Observable<E> {
         return _subject
     }
+
+    deinit {
+        _subject.on(.Completed)
+    }
 }

Tests/RxCocoaTests/Control+RxTests+UIKit.swift

@@ -172,7 +172,8 @@ extension ControlTests {
 // UILabel
 extension ControlTests {
     func testLabel_HasWeakReference() {
-        ensureControlObserverHasWeakReference(UILabel(), { (label: UILabel) -> AnyObserver<NSAttributedString?> in label.rx_attributedText }, { Variable<NSAttributedString?>(nil).asObservable() })
+        let variable = Variable<NSAttributedString?>(nil)
+        ensureControlObserverHasWeakReference(UILabel(), { (label: UILabel) -> AnyObserver<NSAttributedString?> in label.rx_attributedText }, { variable.asObservable() })
     }
 
     func testLabel_NextElementsSetsValue() {

Tests/RxCocoaTests/Control+RxTests.swift

@@ -26,7 +26,7 @@ class ControlTests : RxTest {
 
             let property = propertySelector(control)
 
-            let disposable = variable.bindTo(property)
+            let disposable = variable.asObservable().bindTo(property)
 
             _ = property.subscribe(onNext: { n in
                 lastReturnedPropertyValue = n

Tests/RxSwiftTests/Tests/VariableTest.swift

@@ -15,7 +15,7 @@ class VariableTest : RxTest {
         let a = Variable(1)
         let b = Variable(2)
         
-        let c = Observable.combineLatest(a, b, resultSelector: +)
+        let c = Observable.combineLatest(a.asObservable(), b.asObservable(), resultSelector: +)
         
         var latestValue: Int?
         
@@ -41,6 +41,26 @@ class VariableTest : RxTest {
         XCTAssertEqual(latestValue!, 14)
     }
 
+    func testVariable_sendsCompletedOnDealloc() {
+        var a = Variable(1)
+
+        var latest = 0
+        var completed = false
+        a.asObservable().subscribe(onNext: { n in
+            latest = n
+        }, onCompleted: {
+            completed = true
+        })
+
+        XCTAssertEqual(latest, 1)
+        XCTAssertFalse(completed)
+
+        a = Variable(2)
+
+        XCTAssertEqual(latest, 1)
+        XCTAssertTrue(completed)
+    }
+
     func testVariable_READMEExample() {
         
         // Two simple Rx variables
@@ -49,7 +69,7 @@ class VariableTest : RxTest {
         let b /*: Observable<Int>*/ = Variable(2)
         
         // Computed third variable (or sequence)
-        let c /*: Observable<Int>*/ = Observable.combineLatest(a, b) { $0 + $1 }
+        let c /*: Observable<Int>*/ = Observable.combineLatest(a.asObservable(), b.asObservable()) { $0 + $1 }
         
         // Reading elements from c.
         // This is just a demo example.