Ensure we properly detect update messages for migrations.

app/src/main/java/org/thoughtcrime/securesms/jobs/PushProcessMessageJob.java

@@ -953,6 +953,13 @@ public final class PushProcessMessageJob extends BaseJob {
     try {
       GroupDatabase groupDatabase = DatabaseFactory.getGroupDatabase(context);
 
+      if (message.getMessage().isGroupV2Message()) {
+        Optional<GroupDatabase.GroupRecord> possibleGv1 = groupDatabase.getGroupV1ByExpectedV2(GroupId.v2(message.getMessage().getGroupContext().get().getGroupV2().get().getMasterKey()));
+        if (possibleGv1.isPresent()) {
+          GroupsV1MigrationUtil.performLocalMigration(context, possibleGv1.get().getId().requireV1());
+        }
+      }
+
       long threadId = -1;
 
       if (message.isRecipientUpdate()) {
@@ -965,6 +972,8 @@ public final class PushProcessMessageJob extends BaseJob {
       } else if (message.getMessage().isGroupV2Update()) {
         handleSynchronizeSentGv2Update(content, message);
         threadId = DatabaseFactory.getThreadDatabase(context).getThreadIdFor(getSyncMessageDestination(message));
+      } else if (message.getMessage().isEmptyGroupV2Message()) {
+        // Do nothing
       } else if (message.getMessage().isExpirationUpdate()) {
         threadId = handleSynchronizeSentExpirationUpdate(message);
       } else if (message.getMessage().getReaction().isPresent()) {

libsignal/service/src/main/java/org/whispersystems/signalservice/api/messages/SignalServiceDataMessage.java

@@ -163,6 +163,10 @@ public class SignalServiceDataMessage {
            !hasRenderableContent();
   }
 
+  public boolean isEmptyGroupV2Message() {
+    return isGroupV2Message() && !isGroupV2Update() && !hasRenderableContent();
+  }
+
   /** Contains some user data that affects the conversation */
   public boolean hasRenderableContent() {
     return attachments.isPresent()   ||