Handle case where sessions haven't yet been established in a closed group

SignalServiceKit/src/Loki/Protocol/Session Management/SessionManagementProtocol.swift

@@ -152,6 +152,16 @@ public final class SessionManagementProtocol : NSObject {
         }
     }
 
+    @objc(shouldIgnoreMissingPreKeyBundleExceptionForMessage:to:)
+    public static func shouldIgnoreMissingPreKeyBundleException(for message: TSOutgoingMessage, to hexEncodedPublicKey: String) -> Bool {
+        // When a closed group is created, members try to establish sessions with eachother in the background through
+        // session requests. Until ALL users those session requests were sent to have come online, stored the pre key
+        // bundles contained in the session requests and replied with background messages to finalize the session
+        // creation, a given user won't be able to successfully send a message to all members of a group. This check
+        // is so that until we can do better on this front the user at least won't see this as an error in the UI.
+        return (message.thread as? TSGroupThread)?.groupModel.groupType == .closedGroup
+    }
+
     // MARK: - Receiving
     @objc(handleDecryptionError:forHexEncodedPublicKey:using:)
     public static func handleDecryptionError(_ rawValue: Int32, for hexEncodedPublicKey: String, using transaction: YapDatabaseReadWriteTransaction) {

SignalServiceKit/src/Messages/OWSMessageSender.m

@@ -977,6 +977,14 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
     } else {
         deviceMessages = [self deviceMessagesForMessageSend:messageSend error:&deviceMessagesError];
     }
+
+    // Loki: Remove this when we have shared sender keys
+    // ========
+    if (deviceMessages.count == 0) {
+        return messageSend.success();
+    }
+    // ========
+
     if (deviceMessagesError || !deviceMessages) {
         OWSAssertDebug(deviceMessagesError);
         return messageSend.failure(deviceMessagesError);
@@ -1603,10 +1611,18 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
             // This may involve blocking network requests, so we do it _before_
             // we open a transaction.
 
+            BOOL hasSession = YES;
             if ([LKSessionManagementProtocol isSessionRequiredForMessage:messageSend.message]) {
-                [self throws_ensureRecipientHasSessionForMessageSend:messageSend recipientID:recipientID deviceId:@(OWSDevicePrimaryDeviceId)];
+                hasSession = [self throws_ensureRecipientHasSessionForMessageSend:messageSend recipientID:recipientID deviceId:@(OWSDevicePrimaryDeviceId)];
             }
 
+            // Loki: Remove this when we have shared sender keys
+            // ========
+            if (!hasSession && [LKSessionManagementProtocol shouldIgnoreMissingPreKeyBundleExceptionForMessage:messageSend.message to:recipientID]) {
+                return [NSDictionary new];
+            }
+            // ========
+
             __block NSDictionary *_Nullable messageDict;
             __block NSException *encryptionException;
             [self.dbConnection
@@ -1647,7 +1663,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
     return [messagesArray copy];
 }
 
-- (void)throws_ensureRecipientHasSessionForMessageSend:(OWSMessageSend *)messageSend recipientID:(NSString *)recipientID deviceId:(NSNumber *)deviceId
+- (BOOL)throws_ensureRecipientHasSessionForMessageSend:(OWSMessageSend *)messageSend recipientID:(NSString *)recipientID deviceId:(NSNumber *)deviceId
 {
     OWSAssertDebug(messageSend);
     OWSAssertDebug(deviceId);
@@ -1661,7 +1677,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
         hasSession = [storage containsSession:recipientID deviceId:[deviceId intValue] protocolContext:transaction];
     }];
     if (hasSession) {
-        return;
+        return YES;
     }
     // Discard "typing indicator" messages if there is no existing session with the user.
     BOOL canSafelyBeDiscarded = messageSend.message.isOnline;
@@ -1705,7 +1721,12 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
     */
 
     if (!bundle) {
-        [LKSessionManagementProtocol repairSessionIfNeededForMessage:messageSend.message to:recipientID];
+        TSOutgoingMessage *message = messageSend.message;
+        [LKSessionManagementProtocol repairSessionIfNeededForMessage:message to:recipientID];
+        // Loki: Remove this when we have shared sender keys
+        // ========
+        if ([LKSessionManagementProtocol shouldIgnoreMissingPreKeyBundleExceptionForMessage:message to:recipientID]) { return NO; }
+        // ========
         NSString *missingPrekeyBundleException = @"missingPrekeyBundleException";
         OWSRaiseException(missingPrekeyBundleException, @"Missing pre key bundle for: %@.", recipientID);
     } else {
@@ -1733,6 +1754,7 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
             }
             @throw exception;
         }
+        return YES;
     }
 }