Ensure we're retaining all promises to completion

// FREEBIE

Signal.xcodeproj/project.pbxproj

@@ -100,6 +100,8 @@
 		453D28B71D32BA5F00D523F0 /* OWSDisplayedMessage.m in Sources */ = {isa = PBXBuildFile; fileRef = 453D28B61D32BA5F00D523F0 /* OWSDisplayedMessage.m */; };
 		453D28BA1D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.m in Sources */ = {isa = PBXBuildFile; fileRef = 453D28B91D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.m */; };
 		453D28BB1D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.m in Sources */ = {isa = PBXBuildFile; fileRef = 453D28B91D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.m */; };
+		4542F0961EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4542F0951EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift */; };
+		4542F0971EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4542F0951EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift */; };
 		45464DBC1DFA041F001D3FD6 /* DataChannelMessage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45464DBB1DFA041F001D3FD6 /* DataChannelMessage.swift */; };
 		45666EC61D99483D008FE134 /* OWSAvatarBuilder.m in Sources */ = {isa = PBXBuildFile; fileRef = 45666EC51D99483D008FE134 /* OWSAvatarBuilder.m */; };
 		45666EC91D994C0D008FE134 /* OWSGroupAvatarBuilder.m in Sources */ = {isa = PBXBuildFile; fileRef = 45666EC81D994C0D008FE134 /* OWSGroupAvatarBuilder.m */; };
@@ -437,8 +439,8 @@
 		34B3F86E1E8DF1700035BE1A /* SignalsNavigationController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SignalsNavigationController.m; sourceTree = "<group>"; };
 		34B3F86F1E8DF1700035BE1A /* SignalsViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SignalsViewController.h; sourceTree = "<group>"; };
 		34B3F8701E8DF1700035BE1A /* SignalsViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SignalsViewController.m; sourceTree = "<group>"; };
-		34B3F8981E8DF1B90035BE1A /* TSMessageAdapterTest.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = TSMessageAdapterTest.m; sourceTree = "<group>"; };
 		34B3F89A1E8DF3270035BE1A /* BlockListViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BlockListViewController.h; sourceTree = "<group>"; };
+		34B3F8981E8DF1B90035BE1A /* TSMessageAdapterTest.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = TSMessageAdapterTest.m; sourceTree = "<group>"; };
 		34B3F89B1E8DF3270035BE1A /* BlockListViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = BlockListViewController.m; sourceTree = "<group>"; };
 		34B3F89D1E8DF5490035BE1A /* OWSTableViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSTableViewController.h; sourceTree = "<group>"; };
 		34B3F89E1E8DF5490035BE1A /* OWSTableViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSTableViewController.m; sourceTree = "<group>"; };
@@ -489,6 +491,7 @@
 		453D28B61D32BA5F00D523F0 /* OWSDisplayedMessage.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSDisplayedMessage.m; sourceTree = "<group>"; };
 		453D28B81D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSMessagesBubblesSizeCalculator.h; sourceTree = "<group>"; };
 		453D28B91D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSMessagesBubblesSizeCalculator.m; sourceTree = "<group>"; };
+		4542F0951EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "Promise+retainUntilComplete.swift"; sourceTree = "<group>"; };
 		45464DBB1DFA041F001D3FD6 /* DataChannelMessage.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DataChannelMessage.swift; sourceTree = "<group>"; };
 		454B35071D08EED80026D658 /* mk */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = mk; path = translations/mk.lproj/Localizable.strings; sourceTree = "<group>"; };
 		45666EC41D99483D008FE134 /* OWSAvatarBuilder.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSAvatarBuilder.h; sourceTree = "<group>"; };
@@ -1246,6 +1249,7 @@
 				76EB04FB18170B33006006FC /* Util.h */,
 				45F170D51E315310003FC1F2 /* Weak.swift */,
 				45F170CB1E310E22003FC1F2 /* WeakTimer.swift */,
+				4542F0951EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift */,
 			);
 			path = util;
 			sourceTree = "<group>";
@@ -1990,6 +1994,7 @@
 				34B3F8791E8DF1700035BE1A /* CountryCodeViewController.m in Sources */,
 				4CE0E3771B954546007210CF /* TSAnimatedAdapter.m in Sources */,
 				4531C9C41DD8E6D800F08304 /* JSQMessagesCollectionViewCell+OWS.m in Sources */,
+				4542F0961EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift in Sources */,
 				4516E3FF1DD2193B00DC4206 /* OWS101ExistingUsersBlockOnIdentityChange.m in Sources */,
 				4505C2BF1E648EA300CEBF41 /* ExperienceUpgrade.swift in Sources */,
 				45387B041E36D650005D00B3 /* OWS102MoveLoggingPreferenceToUserDefaults.m in Sources */,
@@ -2169,6 +2174,7 @@
 				45FBC5D21DF8592E00E9B410 /* SignalCall.swift in Sources */,
 				451A13B21E13DED2000A50FD /* CallNotificationsAdapter.swift in Sources */,
 				45C681B81D305A580050903A /* OWSCall.m in Sources */,
+				4542F0971EBB9E9A00C7EE92 /* Promise+retainUntilComplete.swift in Sources */,
 				45855F381D9498A40084F340 /* OWSContactAvatarBuilder.m in Sources */,
 				45DF5DF31DDB843F00C936C7 /* CompareSafetyNumbersActivity.swift in Sources */,
 				456AC8341E3A775E00A3C7FC /* Weak.swift in Sources */,

Signal/src/Models/SyncPushTokensJob.swift

@@ -12,8 +12,6 @@ class SyncPushTokensJob: NSObject {
     let accountManager: AccountManager
     let preferences: PropertyListPreferences
     var uploadOnlyIfStale = true
-    // useful to ensure promise runs to completion
-    var retainCycle: SyncPushTokensJob?
 
     required init(pushManager: PushManager, accountManager: AccountManager, preferences: PropertyListPreferences) {
         self.pushManager = pushManager
@@ -32,14 +30,12 @@ class SyncPushTokensJob: NSObject {
 
     func run() -> Promise<Void> {
         Logger.debug("\(TAG) Starting.")
-        // Make sure we don't GC until completion.
-        self.retainCycle = self
 
         // Required to potentially prompt user for notifications settings
         // before `requestPushTokens` will return.
         self.pushManager.validateUserNotificationSettings()
 
-        return self.requestPushTokens().then { (pushToken: String, voipToken: String) in
+        let runPromise: Promise<Void> = self.requestPushTokens().then { (pushToken: String, voipToken: String) in
             var shouldUploadTokens = !self.uploadOnlyIfStale
             if self.preferences.getPushToken() != pushToken || self.preferences.getVoipToken() != voipToken {
                 Logger.debug("\(self.TAG) push tokens changed.")
@@ -56,9 +52,10 @@ class SyncPushTokensJob: NSObject {
                 Logger.info("\(self.TAG) Recording tokens locally.")
                 return self.recordNewPushTokens(pushToken:pushToken, voipToken:voipToken)
             }
-        }.always {
-            self.retainCycle = nil
         }
+        runPromise.retainUntilComplete()
+
+        return runPromise
     }
 
     private func requestPushTokens() -> Promise<(pushToken: String, voipToken: String)> {

Signal/src/call/CallService.swift

@@ -125,7 +125,7 @@ protocol CallServiceObserver: class {
         didSet {
             AssertIsOnMainThread()
 
-            Logger.debug("\(self.TAG) .peerConnectionClient setter: \(oldValue != nil) -> \(peerConnectionClient != nil) \(peerConnectionClient)")
+            Logger.debug("\(self.TAG) .peerConnectionClient setter: \(oldValue != nil) -> \(peerConnectionClient != nil) \(String(describing: peerConnectionClient))")
         }
     }
 
@@ -141,7 +141,7 @@ protocol CallServiceObserver: class {
             updateIsVideoEnabled()
             updateLockTimerEnabling()
 
-            Logger.debug("\(self.TAG) .call setter: \(oldValue != nil) -> \(call != nil) \(call)")
+            Logger.debug("\(self.TAG) .call setter: \(oldValue != nil) -> \(call != nil) \(String(describing: call))")
 
             for observer in observers {
                 observer.value?.didUpdateCall(call:call)
@@ -368,9 +368,10 @@ protocol CallServiceObserver: class {
 
         if pendingIceUpdateMessages.count > 0 {
             let callMessage = OWSOutgoingCallMessage(thread: thread, iceUpdateMessages: pendingIceUpdateMessages)
-            _ = messageSender.sendCallMessage(callMessage).catch { error in
+            let sendPromise = messageSender.sendCallMessage(callMessage).catch { error in
                 Logger.error("\(self.TAG) failed to send ice updates in \(#function) with error: \(error)")
             }
+            sendPromise.retainUntilComplete()
         }
 
         guard let peerConnectionClient = self.peerConnectionClient else {
@@ -379,7 +380,7 @@ protocol CallServiceObserver: class {
         }
 
         let sessionDescription = RTCSessionDescription(type: .answer, sdp: sessionDescription)
-        _ = peerConnectionClient.setRemoteSessionDescription(sessionDescription).then {
+        let setDescriptionPromise = peerConnectionClient.setRemoteSessionDescription(sessionDescription).then {
             Logger.debug("\(self.TAG) successfully set remote description")
         }.catch { error in
             if let callError = error as? CallError {
@@ -389,6 +390,7 @@ protocol CallServiceObserver: class {
                 self.handleFailedCall(failedCall: call, error: externalError)
             }
         }
+        setDescriptionPromise.retainUntilComplete()
     }
 
     /**
@@ -424,7 +426,8 @@ protocol CallServiceObserver: class {
 
         let busyMessage = OWSCallBusyMessage(callId: call.signalingId)
         let callMessage = OWSOutgoingCallMessage(thread: thread, busyMessage: busyMessage)
-        _ = messageSender.sendCallMessage(callMessage)
+        let sendPromise = messageSender.sendCallMessage(callMessage)
+        sendPromise.retainUntilComplete()
 
         handleMissedCall(call, thread: thread)
     }
@@ -622,7 +625,8 @@ protocol CallServiceObserver: class {
 
         if self.sendIceUpdatesImmediately {
             let callMessage = OWSOutgoingCallMessage(thread: thread, iceUpdateMessage: iceUpdateMessage)
-            _ = self.messageSender.sendCallMessage(callMessage)
+            let sendPromise = self.messageSender.sendCallMessage(callMessage)
+            sendPromise.retainUntilComplete()
         } else {
             // For outgoing messages, we wait to send ice updates until we're sure client received our call message.
             // e.g. if the client has blocked our message due to an identity change, we'd otherwise
@@ -880,11 +884,12 @@ protocol CallServiceObserver: class {
         // If the call hasn't started yet, we don't have a data channel to communicate the hang up. Use Signal Service Message.
         let hangupMessage = OWSCallHangupMessage(callId: call.signalingId)
         let callMessage = OWSOutgoingCallMessage(thread: thread, hangupMessage: hangupMessage)
-        _  = self.messageSender.sendCallMessage(callMessage).then {
+        let sendPromise = self.messageSender.sendCallMessage(callMessage).then {
             Logger.debug("\(self.TAG) successfully sent hangup call message to \(thread)")
         }.catch { error in
             Logger.error("\(self.TAG) failed to send hangup call message to \(thread) with error: \(error)")
         }
+        sendPromise.retainUntilComplete()
 
         terminateCall()
     }

Signal/src/call/Speakerbox/CallKitCallUIAdaptee.swift

@@ -239,7 +239,9 @@ final class CallKitCallUIAdaptee: NSObject, CallUIAdaptee, CXProviderDelegate {
         // We can't wait for long before fulfilling the CXAction, else CallKit will show a "Failed Call". We don't 
         // actually need to wait for the outcome of the handleOutgoingCall promise, because it handles any errors by 
         // manually failing the call.
-        _ = self.callService.handleOutgoingCall(call)
+        let callPromise = self.callService.handleOutgoingCall(call)
+        callPromise.retainUntilComplete()
+
         action.fulfill()
         self.provider.reportOutgoingCall(with: call.localId, startedConnectingAt: nil)
 

Signal/src/util/Promise+retainUntilComplete.swift

@@ -0,0 +1,20 @@
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
+
+import PromiseKit
+
+public extension Promise {
+    /**
+     * Sometimes there isn't a straight forward candidate to retain a promise, in that case we tell the 
+     * promise to self retain, until it completes to avoid the risk it's GC'd before completion.
+     */
+    func retainUntilComplete() {
+        // Unfortunately, there is (currently) no way to surpress the 
+        // compiler warning: "Variable 'retainCycle' was written to, but never read"
+        var retainCycle: Promise<T>? = self
+        self.always {
+            retainCycle = nil
+        }
+    }
+}