Test share

Author: isaac-weisberg

Tests/RxSwiftTests/Anomalies.swift

@@ -176,4 +176,34 @@ extension AnomaliesTest {
             performSharingOperatorsTest(share: op)
         }
     }
+    
+    func testShareReplayOneInitialEmissionDeadlock() {
+        let exp = expectation(description: "`share(replay: 1)` doesn't cause a deadlock in multithreaded environment because it replays with its own lock acquired")
+        
+        let sharedSource = Observable<Void>.create { observer in
+            observer.on(.next(()))
+            return Disposables.create()
+        }
+        
+        let triggerRange = 0..<100
+        
+        let concurrentScheduler = ConcurrentDispatchQueueScheduler(qos: .userInitiated)
+        
+        let multipleSubscriptions = Observable.zip(triggerRange.map { _ in
+            Observable.just(())
+                .observe(on: concurrentScheduler)
+                .flatMap { _ in
+                    sharedSource
+                        .take(1)
+                }
+        })
+        .take(1)
+        
+        _ = multipleSubscriptions.subscribe(onCompleted: {
+            exp.fulfill()
+        })
+        
+        
+        wait(for: [exp], timeout: 5)
+    }
 }