Stage Transform: Stage processing stopped early caused by: Error: preFetch check did not pass

[HappyLoLTroll]

Hi,
I set up multiscrobbler with 3 endpoint and 2 clients, lastfm and listenbrainz.
When an endpoint listens to a song, it is uploaded to multiscrobbler and the "transform" process starts.
For the ListenBrainz client everything works correctly, but for Last.fm I receive this error for every track:

Log

Error: Unexpected error occurred, returning original play.
    at LastfmScrobbler.transformPlay (CWD/src/backend/common/AbstractComponent.ts:401:25)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async LastfmScrobbler.queuePlayingNow (CWD/src/backend/scrobblers/AbstractScrobbleClient.ts:1605:33)
    at async ScrobbleClients.playingNow (CWD/src/backend/scrobblers/ScrobbleClients.ts:512:17)
caused by: TypeError: Cannot read properties of undefined (reading 'lifecycle')
    at LastfmScrobbler.transformPlay (CWD/src/backend/common/AbstractComponent.ts:340:52)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async LastfmScrobbler.queuePlayingNow (CWD/src/backend/scrobblers/AbstractScrobbleClient.ts:1605:33)
    at async ScrobbleClients.playingNow (CWD/src/backend/scrobblers/ScrobbleClients.ts:512:17)
[2026-07-14 10:32:47.721 +0000] DEBUG  : [App] [Scrobblers] [Lastfm - Happy LFM Client] [Play Transform] [preCompare] [eQMlLc] Stage 'MyMB' was skipped
Stage Transform: Stage processing stopped early
    at TransformerManager.handleStage (CWD/src/backend/common/transforms/TransformerManager.ts:157:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async LastfmScrobbler.generateStepFromStage (CWD/src/backend/common/AbstractComponent.ts:442:47)
    at async LastfmScrobbler.transformPlay (CWD/src/backend/common/AbstractComponent.ts:318:46)
    at async LastfmScrobbler.queuePlayingNow (CWD/src/backend/scrobblers/AbstractScrobbleClient.ts:1605:33)
    at async ScrobbleClients.playingNow (CWD/src/backend/scrobblers/ScrobbleClients.ts:512:17)
caused by: Error: preFetch check did not pass
    at MusicbrainzTransformer.handle (CWD/src/backend/common/transforms/AbstractTransformer.ts:89:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async <anonymous> (CWD/src/backend/common/transforms/TransformerManager.ts:153:24)
    at async TransformerManager.handleStage (CWD/src/backend/common/transforms/TransformerManager.ts:152:37)
    at async LastfmScrobbler.generateStepFromStage (CWD/src/backend/common/AbstractComponent.ts:442:47)
    at async LastfmScrobbler.transformPlay (CWD/src/backend/common/AbstractComponent.ts:318:46)
    at async LastfmScrobbler.queuePlayingNow (CWD/src/backend/scrobblers/AbstractScrobbleClient.ts:1605:33)
    at async ScrobbleClients.playingNow (CWD/src/backend/scrobblers/ScrobbleClients.ts:512:17)
caused by: SimpleError: No desired MBIDs (artists,title,album,duration) are missing
    at MusicbrainzTransformer.handlePreFetch (CWD/src/backend/common/transforms/MusicbrainzTransformer.ts:426:19)

Config

{
    "cache": {
        "valkey": "redis://valkey:6379"
    },
  "transformers": [
    {
      "type": "musicbrainz",
      "name": "MyMB",
      "data": {
        "apis": [
          {
            "contact": "redacted"
          }
        ],
        "defaults": {
          "releaseStatusPriority": ["pseudo-release", "official", "sensible", "native"],
          "releaseAllowEmpty": true,
                  "forceSearch": true
        }
      }
    }
  ],
  "debugMode": false,
  "disableWeb": false,
  "sourceDefaults": {
    "maxPollRetries": 2,
    "maxRequestRetries": 2,
    "retryMultiplier": 1.5
  },
  "clientDefaults": {
    "maxRequestRetries": 2,
    "retryMultiplier": 1.5
  },
  "sources": [
    {
        "type": "endpointlz",
        "name": "LZ for Pano PC",
        "id": "myLzPanoPC",
        "enable": true,
        "data": {
        "token": "redacted"
        }
    },
    {
        "type": "endpointlz",
        "name": "LZ for Mobile",
        "id": "myLzMobile",
        "enable": true,
        "data": {
        "token": "redacted"
        }
    },
    {
        "type": "endpointlz",
        "name": "LZ for Pano Az",
        "id": "myLz",
        "enable": true,
        "data": {
        "token": "redacted"
        }
    }
  ],
  "clients": [
    {
        "type": "listenbrainz",
        "name": "Happy LZ Client",
        "id": "brainzClient",
        "enable": true,
        "configureAs": "client",
        "data": {
            "token": "redacted",
            "username": "redacted",
            "url": "https://api.listenbrainz.org"
            },
      "options": {
      "playTransform": {
        "preCompare": [
          {
            "type": "musicbrainz",
            "name": "MyMB"
          }
        ]
      }
    }
    },
    {
    "type": "lastfm",
    "name": "Happy LFM Client",
    "id": "myLastFmClient",
    "enable": true,
    "configureAs": "client",
    "data": {
      "apiKey": "redacted",
      "secret": "redacted",
      "redirectUri": "redacted"
    },
      "options": {
      "playTransform": {
        "preCompare": [
          {
            "type": "musicbrainz",
            "name": "MyMB"
          }
        ]
      }
    }
  }]
}

Am I missing something or there is a bug with this approach?
I also attach the full log of a song.
song.log

I'm using Pano Scrobbler and have configured it to include only the primary artist, so that the MusicBrainz transform can add the remaining artists.

The goal is to have LastFM scrobbles identical to those on Listenbrainz.

Thanks

[FoxxMD]

Thanks for the detailed logs! Can you try docker image

docker pull ghcr.io/foxxmd/multi-scrobbler:edge@sha256:846bebfb0474a952c81a33c70385fc4cb81bf377b2c607306482d9e80192b627

and see if that resolves the error?

[HappyLoLTroll]

I tried the update but I get the same error. I attach the log.
error1.log

For context LB is like this:

with all the artist

LastFM is like this instead:

with only the first artist

[FoxxMD]

Thanks for the reply and logs.

So the error was fixed because this is no longer showing up in the logs

Error: Unexpected error occurred, returning original play.
    at LastfmScrobbler.transformPlay (CWD/src/backend/common/AbstractComponent.ts:401:25)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async LastfmScrobbler.queuePlayingNow (CWD/src/backend/scrobblers/AbstractScrobbleClient.ts:1605:33)
    at async ScrobbleClients.playingNow (CWD/src/backend/scrobblers/ScrobbleClients.ts:512:17)
caused by: TypeError: Cannot read properties of undefined (reading 'lifecycle')

The log line in your current logs

[2026-07-14 14:20:04.321 +0000] DEBUG  : [App] [Scrobblers] [Lastfm - Happy LFM Client] [Play Transform] [preCompare] [OZ8ELs] Stage 'MyMB' was skipped
...
caused by: SimpleError: No desired MBIDs (artists,title,album,duration) are missing

is expected. This is just saying that MS did not need to do any transform because the musicbrainz data was already there.

The reason you are seeing a disconnect with artists on Last.fm vs Listenbrainz is because Last.fm does not allow a scrobble to have multiple artists in the artist field. When a client (MS) tries to send something like artist: SadTurs & KIID feat. Glocky Last.fm will ignore the request entirely. So, instead MS only sends the first artist.

I have confirmed this behavior for scrobbles but I haven't double-checked the behavior is the same when sending playing now. Though I strongly suspect Last.fm would respond the same since the payloads are identical. I will check this shortly.

[HappyLoLTroll]

Ok, thanks for the explanation. I think I'll leave it like it is now.