Allow duplicate message IDs

Some providers, in any case Gmail, allow duplicate message IDs as well

app/src/main/java/eu/faircode/email/Core.java

@@ -1070,20 +1070,18 @@ class Core {
                     Log.i(folder.name + " found as id=" + dup.id +
                             " uid=" + dup.uid + "/" + uid +
                             " msgid=" + msgid + " thread=" + thread);
-                    dup.folder = folder.id; // outbox to sent
 
                     if (dup.uid == null) {
                         Log.i(folder.name + " set uid=" + uid);
+                        dup.folder = folder.id; // outbox to sent
                         dup.uid = uid;
+                        dup.msgid = msgid;
+                        dup.thread = thread;
+                        dup.error = null;
+                        message = dup;
+                        update = true;
                         filter = true;
-                    } else
-                        Log.w(folder.name + " changed uid=" + dup.uid + " -> " + uid);
-
-                    dup.msgid = msgid;
-                    dup.thread = thread;
-                    dup.error = null;
-                    update = true;
-                    message = dup;
+                    }
                 }
             }
 

app/src/main/java/eu/faircode/email/DB.java

@@ -50,7 +50,7 @@ import io.requery.android.database.sqlite.RequerySQLiteOpenHelperFactory;
 // https://developer.android.com/topic/libraries/architecture/room.html
 
 @Database(
-        version = 62,
+        version = 63,
         entities = {
                 EntityIdentity.class,
                 EntityAccount.class,
@@ -676,6 +676,14 @@ public abstract class DB extends RoomDatabase {
                         db.execSQL("ALTER TABLE `account` ADD COLUMN `warning` TEXT");
                     }
                 })
+                .addMigrations(new Migration(62, 63) {
+                    @Override
+                    public void migrate(SupportSQLiteDatabase db) {
+                        Log.i("DB migration from version " + startVersion + " to " + endVersion);
+                        db.execSQL("DROP INDEX index_message_msgid_folder");
+                        db.execSQL("CREATE  INDEX `index_message_msgid` ON `message` (`msgid`)");
+                    }
+                })
                 .build();
     }
 

app/src/main/java/eu/faircode/email/EntityMessage.java

@@ -58,7 +58,7 @@ import static androidx.room.ForeignKey.SET_NULL;
                 @Index(value = {"folder"}),
                 @Index(value = {"identity"}),
                 @Index(value = {"folder", "uid"}, unique = true),
-                @Index(value = {"msgid", "folder"}, unique = true),
+                @Index(value = {"msgid"}),
                 @Index(value = {"thread"}),
                 @Index(value = {"sender"}),
                 @Index(value = {"received"}),