Add some extra preconditions to reaction processing.

app/src/main/java/org/thoughtcrime/securesms/database/MmsSmsDatabase.java

@@ -150,17 +150,17 @@ public class MmsSmsDatabase extends Database {
     return 0;
   }
 
-  public @Nullable MessageRecord getMessageFor(long timestamp, RecipientId author) {
+  public @Nullable MessageRecord getMessageFor(long timestamp, RecipientId authorId) {
-    MmsSmsDatabase db = DatabaseFactory.getMmsSmsDatabase(context);
+    Recipient author = Recipient.resolved(authorId);
 
     try (Cursor cursor = queryTables(PROJECTION, MmsSmsColumns.NORMALIZED_DATE_SENT + " = " + timestamp, null, null)) {
-      MmsSmsDatabase.Reader reader = db.readerFor(cursor);
+      MmsSmsDatabase.Reader reader = readerFor(cursor);
 
       MessageRecord messageRecord;
 
       while ((messageRecord = reader.getNext()) != null) {
-        if ((Recipient.resolved(author).isSelf() && messageRecord.isOutgoing()) ||
+        if ((author.isSelf() && messageRecord.isOutgoing()) ||
-            (!Recipient.resolved(author).isSelf() && messageRecord.getIndividualRecipient().getId().equals(author)))
+            (!author.isSelf() && messageRecord.getIndividualRecipient().getId().equals(authorId)))
         {
           return messageRecord;
         }

app/src/main/java/org/thoughtcrime/securesms/database/ThreadDatabase.java

@@ -1318,7 +1318,7 @@ public class ThreadDatabase extends Database {
     }
   }
 
-  private @Nullable ThreadRecord getThreadRecord(@Nullable Long threadId) {
+  public @Nullable ThreadRecord getThreadRecord(@Nullable Long threadId) {
     if (threadId == null) {
       return null;
     }

app/src/main/java/org/thoughtcrime/securesms/messages/MessageContentProcessor.java

@@ -44,6 +44,7 @@ import org.thoughtcrime.securesms.database.model.MessageRecord;
 import org.thoughtcrime.securesms.database.model.MmsMessageRecord;
 import org.thoughtcrime.securesms.database.model.ReactionRecord;
 import org.thoughtcrime.securesms.database.model.StickerRecord;
+import org.thoughtcrime.securesms.database.model.ThreadRecord;
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
 import org.thoughtcrime.securesms.groups.BadGroupIdException;
 import org.thoughtcrime.securesms.groups.GroupChangeBusyException;
@@ -726,26 +727,49 @@ public final class MessageContentProcessor {
       return;
     }
 
-    Recipient     targetAuthor  = Recipient.externalPush(context, reaction.getTargetAuthor());
+    Recipient     reactionAuthor = Recipient.externalHighTrustPush(context, content.getSender());
-    MessageRecord targetMessage = DatabaseFactory.getMmsSmsDatabase(context).getMessageFor(reaction.getTargetSentTimestamp(), targetAuthor.getId());
+    Recipient     targetAuthor   = Recipient.externalPush(context, reaction.getTargetAuthor());
+    MessageRecord targetMessage  = DatabaseFactory.getMmsSmsDatabase(context).getMessageFor(reaction.getTargetSentTimestamp(), targetAuthor.getId());
 
-    if (targetMessage != null && !targetMessage.isRemoteDelete()) {
+    if (targetMessage == null) {
-      Recipient       reactionAuthor = Recipient.externalHighTrustPush(context, content.getSender());
+      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Could not find matching message! Putting it in the early message cache. timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
-      MessageDatabase db             = targetMessage.isMms() ? DatabaseFactory.getMmsDatabase(context) : DatabaseFactory.getSmsDatabase(context);
-
-      if (reaction.isRemove()) {
-        db.deleteReaction(targetMessage.getId(), reactionAuthor.getId());
-        ApplicationDependencies.getMessageNotifier().updateNotification(context);
-      } else {
-        ReactionRecord reactionRecord = new ReactionRecord(reaction.getEmoji(), reactionAuthor.getId(), message.getTimestamp(), System.currentTimeMillis());
-        db.addReaction(targetMessage.getId(), reactionRecord);
-        ApplicationDependencies.getMessageNotifier().updateNotification(context, targetMessage.getThreadId(), false);
-      }
-    } else if (targetMessage != null) {
-      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Found a matching message, but it's flagged as remotely deleted. timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
-    } else {
-      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Could not find matching message! timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
       ApplicationDependencies.getEarlyMessageCache().store(targetAuthor.getId(), reaction.getTargetSentTimestamp(), content);
+      return;
+    }
+
+    if (targetMessage.isRemoteDelete()) {
+      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Found a matching message, but it's flagged as remotely deleted. timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
+      return;
+    }
+
+    ThreadRecord targetThread = DatabaseFactory.getThreadDatabase(context).getThreadRecord(targetMessage.getThreadId());
+
+    if (targetThread == null) {
+      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Could not find a thread for the message! timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
+      return;
+    }
+
+    Recipient threadRecipient = targetThread.getRecipient().resolve();
+
+    if (threadRecipient.isGroup() && !threadRecipient.getParticipants().contains(reactionAuthor)) {
+      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Reaction author is not in the group! timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
+      return;
+    }
+
+    if (!threadRecipient.isGroup() && !reactionAuthor.equals(threadRecipient) && !reactionAuthor.isSelf()) {
+      warn(String.valueOf(content.getTimestamp()), "[handleReaction] Reaction author is not a part of the 1:1 thread! timestamp: " + reaction.getTargetSentTimestamp() + "  author: " + targetAuthor.getId());
+      return;
+    }
+
+    MessageDatabase db = targetMessage.isMms() ? DatabaseFactory.getMmsDatabase(context) : DatabaseFactory.getSmsDatabase(context);
+
+    if (reaction.isRemove()) {
+      db.deleteReaction(targetMessage.getId(), reactionAuthor.getId());
+      ApplicationDependencies.getMessageNotifier().updateNotification(context);
+    } else {
+      ReactionRecord reactionRecord = new ReactionRecord(reaction.getEmoji(), reactionAuthor.getId(), message.getTimestamp(), System.currentTimeMillis());
+      db.addReaction(targetMessage.getId(), reactionRecord);
+      ApplicationDependencies.getMessageNotifier().updateNotification(context, targetMessage.getThreadId(), false);
     }
   }