Fix: No contacts/groups after initial device link

The server caches your device list on the websocket, so sending on the
websocket to a just-linked device will always fail. We could close/open the
websocket, but that might be disruptive in it's own way. Instead we'll closely
mirror the Android approach, where WebSocket sends are attempted only one time,
and failure is handled by falling back to the original REST approach.

So note: we don't do any special handling of failures on the websocket
(409/410). We simply retry it with REST which will handle the 409/410/etc.

Consequently, we don't want to decrement our retry count for websocket sends.

SignalServiceKit/src/Messages/OWSMessageSender.m

@@ -625,11 +625,12 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
             }
 
             [self sendMessageToService:message
-                             recipient:recipient
-                                thread:thread
-                              attempts:OWSMessageSenderRetryAttempts
-                               success:successHandler
-                               failure:failureHandler];
+                              recipient:recipient
+                                 thread:thread
+                               attempts:OWSMessageSenderRetryAttempts
+                useWebsocketIfAvailable:YES
+                                success:successHandler
+                                failure:failureHandler];
         } else {
             // Neither a group nor contact thread? This should never happen.
             OWSFail(@"%@ Unknown message type: %@", self.logTag, NSStringFromClass([message class]));
@@ -652,6 +653,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         recipient:recipient
         thread:thread
         attempts:OWSMessageSenderRetryAttempts
+        useWebsocketIfAvailable:YES
         success:^{
             [futureSource trySetResult:@1];
         }
@@ -772,7 +774,8 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
 - (void)sendMessageToService:(TSOutgoingMessage *)message
                    recipient:(SignalRecipient *)recipient
                       thread:(nullable TSThread *)thread
-                    attempts:(int)remainingAttempts
+                    attempts:(int)remainingAttemptsParam
+     useWebsocketIfAvailable:(BOOL)useWebsocketIfAvailable
                      success:(void (^)(void))successHandler
                      failure:(RetryableFailureHandler)failureHandler
 {
@@ -806,7 +809,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         return failureHandler(error);
     }
 
-    if (remainingAttempts <= 0) {
+    if (remainingAttemptsParam <= 0) {
         // We should always fail with a specific error.
         OWSProdFail([OWSAnalyticsEvents messageSenderErrorGenericSendFailure]);
 
@@ -814,7 +817,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         [error setIsRetryable:YES];
         return failureHandler(error);
     }
-    remainingAttempts -= 1;
+    int remainingAttempts = remainingAttemptsParam - 1;
 
     NSArray<NSDictionary *> *deviceMessages;
     @try {
@@ -978,7 +981,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
                                                                      messages:deviceMessages
                                                                         relay:recipient.relay
                                                                     timeStamp:message.timestamp];
-    if (TSSocketManager.canMakeRequests) {
+    if (useWebsocketIfAvailable && TSSocketManager.canMakeRequests) {
         [TSSocketManager.sharedManager makeRequest:request
             success:^(id _Nullable responseObject) {
                 [self messageSendDidSucceed:message
@@ -988,19 +991,21 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
                                     success:successHandler];
             }
             failure:^(NSInteger statusCode, NSData *_Nullable responseData, NSError *error) {
-                [self messageSendDidFail:message
-                               recipient:recipient
-                                  thread:thread
-                           isLocalNumber:isLocalNumber
-                          deviceMessages:deviceMessages
-                       remainingAttempts:remainingAttempts
-                              statusCode:statusCode
-                                   error:error
-                            responseData:responseData
-                                 success:successHandler
-                                 failure:failureHandler];
+                // Websockets can fail in different ways, so we don't decrement remainingAttempts for websocket failure.
+                // Instead we fall back to REST, which will decrement retries.
+                // e.g. after linking a new device, sync messages will fail until the websocket re-opens.
+                [self sendMessageToService:message
+                                  recipient:recipient
+                                     thread:thread
+                                   attempts:remainingAttemptsParam
+                    useWebsocketIfAvailable:NO
+                                    success:successHandler
+                                    failure:failureHandler];
             }];
     } else {
+        if (!useWebsocketIfAvailable && TSSocketManager.canMakeRequests) {
+            DDLogDebug(@"%@ in %s falling back to REST since first attempt failed.", self.logTag, __PRETTY_FUNCTION__);
+        }
         [self.networkManager makeRequest:request
             success:^(NSURLSessionDataTask *task, id responseObject) {
                 [self messageSendDidSucceed:message
@@ -1098,11 +1103,12 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         dispatch_async([OWSDispatch sendingQueue], ^{
             DDLogDebug(@"%@ Retrying: %@", self.logTag, message.debugDescription);
             [self sendMessageToService:message
-                             recipient:recipient
-                                thread:thread
-                              attempts:remainingAttempts
-                               success:successHandler
-                               failure:failureHandler];
+                              recipient:recipient
+                                 thread:thread
+                               attempts:remainingAttempts
+                useWebsocketIfAvailable:NO
+                                success:successHandler
+                                failure:failureHandler];
         });
     };
 
@@ -1250,6 +1256,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         recipient:[SignalRecipient selfRecipient]
         thread:message.thread
         attempts:OWSMessageSenderRetryAttempts
+        useWebsocketIfAvailable:YES
         success:^{
             DDLogInfo(@"Successfully sent sync transcript.");
         }