Use of undefined in plugins/breath.js

[wAIfu-DEV]

• The FAQ doesn't contain a resolution to my issue

Versions

• mineflayer: 4.23.0
• server: vanilla LAN 1.16
• node: 20.9.0 (x64)

Detailed description of a problem

Error arises at spawn of bot, forcing a shutdown.

Here is the error message:

C:\Users\<user>\Desktop\mineflayerTest\node_modules\mineflayer\lib\plugins\breath.js:16
        bot.oxygenLevel = Math.round(packet.metadata[1].value / 15)
                                                        ^

TypeError: Cannot read properties of undefined (reading 'value')
    at Client.<anonymous> (C:\Users\<user>\Desktop\mineflayerTest\node_modules\mineflayer\lib\plugins\breath.js:16:57)
    at Client.emit (node:events:526:35)
    at emitPacket (C:\Users\<user>\Desktop\mineflayerTest\node_modules\minecraft-protocol\src\client.js:83:12)
    at FullPacketParser.<anonymous> (C:\Users\<user>\Desktop\mineflayerTest\node_modules\minecraft-protocol\src\client.js:112:9)
    at FullPacketParser.emit (node:events:514:28)
    at addChunk (C:\Users\<user>\Desktop\mineflayerTest\node_modules\readable-stream\lib\internal\streams\readable.js:321:12)
    at readableAddChunk (C:\Users\<user>\Desktop\mineflayerTest\node_modules\readable-stream\lib\internal\streams\readable.js:298:9)
    at Readable.push (C:\Users\<user>\Desktop\mineflayerTest\node_modules\readable-stream\lib\internal\streams\readable.js:244:10)
    at FullPacketParser._transform (C:\Users\<user>\Desktop\mineflayerTest\node_modules\protodef\src\serializer.js:89:10)
    at Transform._write (C:\Users\<user>\Desktop\mineflayerTest\node_modules\readable-stream\lib\internal\streams\transform.js:153:8)

The concerned piece of code is as follow:

function inject (bot) {
  if (bot.supportFeature('mcDataHasEntityMetadata')) {
    // this is handled inside entities.js. We don't yet have entity metadataKeys for all versions but once we do
    // we can delete the numerical checks here and in entities.js https://github.com/extremeheat/mineflayer/blob/eb9982aa04973b0086aac68a2847005d77f01a3d/lib/plugins/entities.js#L469
    return
  }
  bot._client.on('entity_metadata', (packet) => {
    if (!bot.entity) return
    if (bot.entity.id !== packet.entityId) return
    for (const metadata of packet.metadata) {
      if (metadata.key === 1) {
        bot.oxygenLevel = Math.round(packet.metadata[1].value / 15) // <- this causes the error, packet.metadata[1] may be undefined, use metadata instead
        bot.emit('breath')
      }
    }
  })
}

Using the following code, here is the log of metadata and packet:

metadata: { key: 1, type: 1, value: 252 }
packet: { entityId: <id>, metadata: [ { key: 1, type: 1, value: 252 } ] }

As you can observe, packet.metdata[1] does not exist.

Fix

for (const metadata of packet.metadata) {
      if (metadata.key === 1) {
        bot.oxygenLevel = Math.round(metadata.value / 15) // <- this fixes it
        bot.emit('breath')
      }
    }

Expected behavior

Not to crash at spawn :^)

[wAIfu-DEV]

also sorry for not providing the fix as a pull request, I have 0 idea how those work

[rom1504]

Press edit on the file in GitHub UI then press open PR, that's it

…

On Fri, Dec 27, 2024, 21:20 wAIfu-DEV ***@***.***> wrote: also sorry for not providing the fix as a pull request, I have 0 idea how those work — Reply to this email directly, view it on GitHub <#3534 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAR437Q4UWBRFOAEZ6HPRCT2HWZBRAVCNFSM6AAAAABUJBUTP2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKNRUGAYDMNRXGE> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[wAIfu-DEV]

fix was merged