Anuken/Mindustry · error · RuntimeException

Objectives bytes too long:

Error message

Objectives bytes too long: 

What it means

readObjectives() reads JSON-serialized MapObjectives. It reads a 4-byte length and throws RuntimeException if length >= 60_000 bytes. It bounds map-objective payloads (sent with map state) against memory abuse.

Source

Thrown at core/src/mindustry/io/TypeIO.java:942

    public static Rules readRules(Reads read){
        int length = read.i();
        //this is only called clientside, but the byte limit is reasonable either way...
        if(length > 100_000) throw new ArcRuntimeException("Rules too long");
        String string = new String(read.b(new byte[length]), charset);
        return JsonIO.read(Rules.class, string);
    }

    public static void writeObjectives(Writes write, MapObjectives executor){
        String string = JsonIO.write(executor);
        byte[] bytes = string.getBytes(charset);
        write.i(bytes.length);
        write.b(bytes);
    }

    public static MapObjectives readObjectives(Reads read){
        int length = read.i();
        if(length >= 60_000) throw new RuntimeException("Objectives bytes too long: " + length);
        String string = new String(read.b(new byte[length]), charset);
        return JsonIO.read(MapObjectives.class, string);
    }

    public static void writeObjectiveMarker(Writes write, ObjectiveMarker marker){
        String string = JsonIO.json.toJson(marker, MapObjectives.ObjectiveMarker.class);
        byte[] bytes = string.getBytes(charset);
        write.i(bytes.length);
        write.b(bytes);
    }

    public static ObjectiveMarker readObjectiveMarker(Reads read){
        int length = read.i();
        if(length > maxByteArraySize) throw new ArcRuntimeException("Objective marker too long");
        String string = new String(read.b(new byte[length]), charset);
        return JsonIO.read(MapObjectives.ObjectiveMarker.class, string);
    }

View on GitHub (pinned to f695ad7e60)

Solutions

1. Reduce the number and complexity of map objectives so JSON stays under 60KB.
2. Split large objective state across multiple markers or out-of-band.

// Before writing objectives, check serialized size against the read cap.
String json = JsonIO.write(executor);
if(json.getBytes(java.nio.charset.StandardCharsets.UTF_8).length >= 60_000){
    throw new IllegalStateException("Objectives JSON too large");
}

try { MapObjectives o = TypeIO.readObjectives(read); }
catch(RuntimeException e){ Log.err("Objectives payload too large", e); /* handle */ }

When it happens

Trigger: A map-objectives packet whose int length field is >= 60_000.

Common situations: A map with very many objectives; a custom campaign map; corruption; a malicious source.

Related errors

• Objective marker too long
• Invalid array size: {}
• Invalid array size:
• Queue too long:
• Too many plans:

AI-assisted analysis of Anuken/Mindustry@f695ad7e60 (2026-08-14). Data as JSON: /api/errors/d92ae58916f847cc. Report an issue: GitHub.