Fix usernames showing as "null" and NPE related to primaryGroup not copying correctly

common/src/main/java/me/lucko/luckperms/commands/user/UserMainCommand.java

@@ -84,7 +84,10 @@ public class UserMainCommand extends MainCommand<User> {
             }
         }
 
-        if (!plugin.getDatastore().loadUser(u, "null")) {
+        String name = plugin.getDatastore().getName(u);
+        if (name == null) name = "null";
+
+        if (!plugin.getDatastore().loadUser(u, name)) {
             Message.LOADING_ERROR.send(sender);
         }
 

common/src/main/java/me/lucko/luckperms/storage/Datastore.java

@@ -87,6 +87,7 @@ public abstract class Datastore {
     public abstract boolean deleteTrack(Track track);
     public abstract boolean saveUUIDData(String username, UUID uuid);
     public abstract UUID getUUID(String username);
+    public abstract String getName(UUID uuid);
 
 
 
@@ -219,4 +220,11 @@ public abstract class Datastore {
             doSync(() -> callback.onComplete(result));
         });
     }
+
+    public void getName(UUID uuid, Callback<String> callback) {
+        doAsync(() -> {
+            String result = getName(uuid);
+            doSync(() -> callback.onComplete(result));
+        });
+    }
 }

common/src/main/java/me/lucko/luckperms/storage/methods/FlatfileDatastore.java

@@ -612,6 +612,16 @@ public class FlatfileDatastore extends Datastore {
         return UUID.fromString(uuidCache.get(username));
     }
 
+    @Override
+    public String getName(UUID uuid) {
+        for (Map.Entry<String, String> e : uuidCache.entrySet()) {
+            if (e.getValue().equalsIgnoreCase(uuid.toString())) {
+                return e.getKey();
+            }
+        }
+        return null;
+    }
+
     interface WriteOperation {
         boolean onRun(JsonWriter writer) throws IOException;
     }

common/src/main/java/me/lucko/luckperms/storage/methods/MongoDBDatastore.java

@@ -413,6 +413,20 @@ public class MongoDBDatastore extends Datastore {
         }, null);
     }
 
+    @Override
+    public String getName(UUID uuid) {
+        return call(() -> {
+            MongoCollection<Document> c = database.getCollection("uuid");
+
+            try (MongoCursor<Document> cursor = c.find(new Document("_id", uuid)).iterator()) {
+                if (cursor.hasNext()) {
+                    return cursor.next().get("name", String.class);
+                }
+            }
+            return null;
+        }, null);
+    }
+
     private static <T> T call(Callable<T> c, T def) {
         try {
             return c.call();

common/src/main/java/me/lucko/luckperms/storage/methods/SQLDatastore.java

@@ -71,6 +71,7 @@ abstract class SQLDatastore extends Datastore {
 
     private static final String UUIDCACHE_INSERT = "INSERT INTO lp_uuid VALUES(?, ?)";
     private static final String UUIDCACHE_SELECT = "SELECT uuid FROM lp_uuid WHERE name=?";
+    private static final String UUIDCACHE_SELECT_NAME = "SELECT name FROM lp_uuid WHERE uuid=?";
     private static final String UUIDCACHE_UPDATE = "UPDATE lp_uuid SET uuid=? WHERE name=?";
 
     private static final String ACTION_INSERT = "INSERT INTO lp_actions(`time`, `actor_uuid`, `actor_name`, `type`, `acted_uuid`, `acted_name`, `action`) VALUES(?, ?, ?, ?, ?, ?, ?)";
@@ -541,6 +542,30 @@ abstract class SQLDatastore extends Datastore {
         return success ? uuid[0] : null;
     }
 
+    @Override
+    public String getName(UUID uuid) {
+        final String u = uuid.toString();
+        final String[] name = {null};
+
+        boolean success = runQuery(new QueryRS(UUIDCACHE_SELECT_NAME) {
+            @Override
+            void onRun(PreparedStatement preparedStatement) throws SQLException {
+                preparedStatement.setString(1, u);
+            }
+
+            @Override
+            boolean onResult(ResultSet resultSet) throws SQLException {
+                if (resultSet.next()) {
+                    name[0] = resultSet.getString("name");
+                    return true;
+                }
+                return false;
+            }
+        });
+
+        return success ? name[0] : null;
+    }
+
     private class Query extends QueryPS {
         Query(String query) {
             super(query);

common/src/main/java/me/lucko/luckperms/users/UserManager.java

@@ -63,6 +63,7 @@ public abstract class UserManager extends AbstractManager<UUID, User> {
     public void copy(User from, User to) {
         to.setNodes(from.getNodes());
         to.setPrimaryGroup(from.getPrimaryGroup());
+        giveDefaultIfNeeded(to, true);
         to.refreshPermissions();
     }