Fixed issue with NSControl.rx.value multiple observers

When multiple observers want to look at NSControl.rx.value, only one would get updates because
the returned observable wasn't shared(). This is examplified by the new test added to NSButton

This also solves the issue of observers with varying types

Author: fpillet

RxCocoa/macOS/NSControl+Rx.swift

@@ -36,9 +36,11 @@ extension Reactive where Base: NSControl {
                 }
 
                 return observer
-            }.takeUntil(self.deallocated)
+            }
+			.takeUntil(self.deallocated)
+			.share()
         }
-        
+
         return ControlEvent(events: source)
     }
 
@@ -47,25 +49,27 @@ extension Reactive where Base: NSControl {
     static func value<C: AnyObject, T>(_ control: C, getter: @escaping (C) -> T, setter: @escaping (C, T) -> Void) -> ControlProperty<T> {
         MainScheduler.ensureExecutingOnScheduler()
 
-        let source = (control as! NSObject).rx.lazyInstanceObservable(&rx_value_key) { () -> Observable<T> in
-            return Observable.create { [weak weakControl = control] (observer: AnyObserver<T>) in
+        let source = (control as! NSObject).rx.lazyInstanceObservable(&rx_value_key) { () -> Observable<Void> in
+            return Observable.create { [weak weakControl = control] (observer: AnyObserver<Void>) in
                 guard let control = weakControl else {
                     observer.on(.completed)
                     return Disposables.create()
                 }
 
-                observer.on(.next(getter(control)))
+                observer.on(.next(()))
 
                 let observer = ControlTarget(control: control as! NSControl) { _ in
-                    if let control = weakControl {
-                        observer.on(.next(getter(control)))
+                    if weakControl != nil {
+                        observer.on(.next(()))
                     }
                 }
-                
+				
                 return observer
             }
-            .takeUntil((control as! NSObject).rx.deallocated)
-        }
+			.takeUntil((control as! NSObject).rx.deallocated)
+			.share(replay: 1, scope: .forever)
+		}
+		.map { [unowned control] _ in getter(control) }
 
         let bindingObserver = UIBindingObserver(UIElement: control, binding: setter)
 

Tests/RxCocoaTests/NSButton+RxTests.swift

@@ -39,4 +39,23 @@ extension NSButtonTests {
 
         XCTAssertEqual(button.state, NSControl.StateValue.off)
     }
+	
+	func testButton_multipleObservers() {
+		let button = NSButton(frame: CGRect(x: 0, y: 0, width: 1, height: 1))
+		var value1: NSControl.StateValue? = nil
+		var value2: NSControl.StateValue? = nil
+
+		_ = Observable.just(NSControl.StateValue.off).bind(to: button.rx.state)
+		_ = button.rx.state.subscribe(onNext: { value1 = $0 })
+		_ = button.rx.state.subscribe(onNext: { value2 = $0 })
+		_ = Observable.just(NSControl.StateValue.on).bind(to: button.rx.state)
+
+		if let target = button.target, let action = button.action {
+			_ = target.perform(action, with: button)
+		}
+
+		XCTAssertEqual(button.state, NSControl.StateValue.on)
+		XCTAssertEqual(value1, NSControl.StateValue.on)
+		XCTAssertEqual(value2, NSControl.StateValue.on)
+	}
 }