TypeError: Cannot read properties of undefined (reading 'passengers')

[TheRealPerson98]

Versions

• mineflayer: Latest
• server: vanilla/spigot/paper Latest
• node: 22.13.1

When joining some servers that have books / or nothing sometimes on join u get

lib\plugins\entities.js:841

TypeError: Cannot read properties of undefined (reading 'passengers')
    at Client.<anonymous> (C:\ops/mineflayer\lib\plugins\entities.js:841:17)
    at Client.emit (node:events:517:28)
    at emitPacket (C:\opsminecraft-protocol\src\client.js:84:12)
    at Array.forEach (<anonymous>)
    at FullPacketParser.<anonymous> (C:REDACTEDnode_modules\minecraft-protocol\src\client.js:99:26)
    at FullPacketParser.emit (node:events:517:28)
    at addChunk (C:REDACTEDnode_modules\readable-stream\lib\internal\streams\readable.js:323:12)
    at readableAddChunk (C:REDACTEDnode_modules\readable-stream\lib\internal\streams\readable.js:300:9)
    at Readable.push (C:REDACTEDnode_modules\readable-stream\lib\internal\streams\readable.js:246:10)
    at FullPacketParser._transform (C:REDACTEDnode_modules\protodef\src\serializer.js:89:10)

also a null on getting the servers dim but i don't have that error

closed my pull i don't have the time to dig deeper into the issue

[bowoflare]

I am running into this same issue, do you know any fixes?

[TheRealPerson98]

I just forked it and added null checks to it bc nothing im doing is using passengers

[notegorkaa]

which minecraft version?

[mrab54]

I'm seeing this on 1.21 java

[hilbix]

Same for MC 1.20.4, Mineflayer 4.26.0, Node.js v18.19.0. Downgrade to 4.25 works:

package.json:

{
  "dependencies":
    { "mineflayer": "=4.25.0"
    }
}

Following code:

#!/usr/bin/env nodejs
'use strict';

const mineflayer = require('mineflayer');
const B = mineflayer.createBot({ host:'127.0.0.1', username:'t', hideErrors:false });
const D = console.error;
B.once('spawn', () => D('spawn', B.version));
B.once('end',   () => process.exit(D('END')));

If I replace the = with ^ in package.json (and then npm update), it crashes within 1 minute. (Note that I have some entities in Minecarts.)

[DatArnoGuy]

This is happening to me too. MC 1.21.4, online mode server, NodeJS v22.13.1, mineflayer 4.26.0

[deinemuttermitbutter]

happens to me too, nodejs: 22.13.1 ; mineflayer: 4.26.0 ; minecraft: 1.21.4 ; device: raspberry pi

[soswi]

So it was bugging in my case because a server allowed to ride other players so it didn't know what to do with it. I've rewrited that listener and it works now.

bot._client.on('set_passengers', ({ entityId, passengers }) => {
    if (!passengers || !Array.isArray(passengers)) {
        console.warn("[WARN] `passengers` is undefined or not an array for entityId:", entityId);
        return;
    }

    const passengerEntities = passengers
        .map(passengerId => bot.entities[passengerId] || null) // Chechking if they exist
        .filter(entity => entity !== null); // We get rid of null

    const vehicle = bot.entities[entityId] || null; // Checking if vehicles exist

    for (const passengerEntity of passengerEntities) {
        if (!passengerEntity) continue; // We skip if they don't exist

        const originalVehicle = passengerEntity.vehicle;
        if (originalVehicle && originalVehicle.passengers) {
            const index = originalVehicle.passengers.indexOf(passengerEntity);
            if (index !== -1) {
                originalVehicle.passengers.splice(index, 1);
            }
        }
        passengerEntity.vehicle = vehicle;

        if (vehicle) {
            if (!vehicle.passengers) vehicle.passengers = []; // We make sure that `passengers` exist
            vehicle.passengers.push(passengerEntity);
        }
    }

    if (passengers.includes(bot.entity.id)) {
        const originalVehicle = bot.vehicle;
        if (entityId === -1) {
            bot.vehicle = null;
            bot.emit('dismount', originalVehicle);
        } else {
            bot.vehicle = bot.entities[entityId] || null;
            bot.emit('mount');
        }
    }
});