Anuken/Mindustry · error · RuntimeException

Queue too long:

Error message

Queue too long: 

What it means

readPlansQueueNet() reads a network-synced build-plan queue. After reading an int count it throws if count > maxSyncedPlans (20). This caps how many BuildPlans a single sync packet can carry to bound processing and bandwidth. Note the save-path readPlansQueue (TypeIO.java:602) deliberately has no cap.

Source

Thrown at core/src/mindustry/io/TypeIO.java:594

    //on the network, plans must be capped by size
    public static void writePlansQueueNet(Writes write, Queue<BuildPlan> plans){
        if(plans == null){
            write.i(-1);
            return;
        }

        int used = getMaxPlans(plans);

        write.i(used);
        for(int i = 0; i < used; i++){
            writePlan(write, plans.get(i));
        }
    }

    public static Queue<BuildPlan> readPlansQueueNet(Reads read){
        int used = read.i();
        if(used == -1) return null;
        if(used > maxSyncedPlans) throw new RuntimeException("Queue too long: " + used);
        var out = new Queue<BuildPlan>();
        for(int i = 0; i < used; i++){
            out.add(readPlan(read));
        }
        return out;
    }

    public static Queue<BuildPlan> readPlansQueue(Reads read){
        int used = read.i();
        if(used == -1) return null;
        //this is ONLY used in saves, so don't enforce a max size, it can be anything.
        var out = new Queue<BuildPlan>();
        for(int i = 0; i < used; i++){
            out.add(readPlan(read));
        }
        return out;
    }

View on GitHub (pinned to f695ad7e60)

Solutions

1. Limit the number of plans queued/sent per network sync to <= 20.
2. Server: catch the RuntimeException and kick the sender.

Example fix

// before
queue.addAll(manyPlans); // > 20 in one sync
TypeIO.writePlansQueueNet(write, queue);

// after
Queue<BuildPlan> capped = new Queue<>();
for(int i = 0; i < Math.min(maxSyncedPlans, manyPlans.size); i++) capped.add(manyPlans.get(i));
TypeIO.writePlansQueueNet(write, capped);

// Before syncing, ensure the queue fits the network cap.
if(plans.size > 20){
    throw new IllegalStateException("Too many plans to sync: " + plans.size);
}

try { Queue<BuildPlan> q = TypeIO.readPlansQueueNet(read); }
catch(RuntimeException e){ Log.err("Build-plan sync too long", e); con.kick("Invalid packet."); }

When it happens

Trigger: A build-plan sync packet's int count field exceeds 20.

Common situations: A client queueing more than 20 plans in one sync; a buggy mod; a malicious client.

Related errors

• Too many plans:
• Invalid array size: {}
• Invalid array size:
• Unknown plan config object type:
• Rules too long

AI-assisted analysis of Anuken/Mindustry@f695ad7e60 (2026-08-14). Data as JSON: /api/errors/6da2fb97cf799782. Report an issue: GitHub.