Don't set content data in LKEphemeralMessage.

SignalServiceKit/src/Loki/Messaging/LKEphemeralMessage.m

@@ -1,5 +1,6 @@
 #import "LKEphemeralMessage.h"
 #import <SignalCoreKit/NSDate+OWS.h>
+#import <SignalServiceKit/SignalServiceKit-Swift.h>
 
 @implementation LKEphemeralMessage
 
@@ -8,6 +9,20 @@
         expiresInSeconds:0 expireStartedAt:0 isVoiceMessage:NO groupMetaMessage:TSGroupMetaMessageUnspecified quotedMessage:nil contactShare:nil linkPreview:nil];
 }
 
+// An EphemeralMessage does not have any data message in the content
+- (nullable NSData *)buildPlainTextData:(SignalRecipient *)recipient
+{
+    NSError *error;
+    SSKProtoContentBuilder *contentBuilder = [self contentBuilder:recipient];
+    
+    NSData *_Nullable contentData = [contentBuilder buildSerializedDataAndReturnError:&error];
+    if (error || !contentData) {
+        OWSFailDebug(@"could not serialize protobuf: %@", error);
+        return nil;
+    }
+    return contentData;
+}
+
 - (BOOL)shouldSyncTranscript { return NO; }
 - (BOOL)shouldBeSaved { return NO; }
 

SignalServiceKit/src/Messages/OWSMessageManager.m

@@ -1512,8 +1512,8 @@ NS_ASSUME_NONNULL_BEGIN
             [existingFriendRequestMessage saveFriendRequestStatus:LKMessageFriendRequestStatusAccepted withTransaction:transaction];
         }
         // The two lines below are equivalent to calling [ThreadUtil enqueueAcceptFriendRequestMessageInThread:thread]
-        LKEphemeralMessage *emptyMessage = [[LKEphemeralMessage alloc] initInThread:thread];
+        LKEphemeralMessage *backgroundMessage = [[LKEphemeralMessage alloc] initInThread:thread];
-        [self.messageSenderJobQueue addMessage:emptyMessage transaction:transaction];
+        [self.messageSenderJobQueue addMessage:backgroundMessage transaction:transaction];
     } else if (!thread.isContactFriend) {
         // Checking that the sender of the message isn't already a friend is necessary because otherwise
         // the following situation can occur: Alice and Bob are friends. Bob loses his database and his