mongodb/node-mongodb-native · error · MongoUnexpectedServerResponseError

Error with validation data

Error message

Error with validation data

What it means

Thrown by ValidateCollectionOperation.handleOk when the server's validate response includes a 'result' field that is neither null nor a string. The driver expects result to be a textual summary string (or absent); any non-string result indicates an unexpected/malformed server response. MongoUnexpectedServerResponseError - the server replied with a shape the driver cannot interpret.

Source

Thrown at src/operations/validate_collection.ts:42

    this.collectionName = collectionName;
  }

  override get commandName() {
    return 'validate' as const;
  }

  override buildCommandDocument(_connection: Connection, _session?: ClientSession): Document {
    // Decorate command with extra options
    return {
      validate: this.collectionName,
      ...Object.fromEntries(Object.entries(this.options).filter(entry => entry[0] !== 'session'))
    };
  }

  override handleOk(response: InstanceType<typeof this.SERVER_COMMAND_RESPONSE_TYPE>): Document {
    const result = super.handleOk(response);
    if (result.result != null && typeof result.result !== 'string')
      throw new MongoUnexpectedServerResponseError('Error with validation data');
    if (result.result != null && result.result.match(/exception|corrupt/) != null)
      throw new MongoUnexpectedServerResponseError(`Invalid collection ${this.collectionName}`);
    if (result.valid != null && !result.valid)
      throw new MongoUnexpectedServerResponseError(`Invalid collection ${this.collectionName}`);

    return response;
  }
}

View on GitHub (pinned to 3366c21a63)

Solutions

1. Check server and driver versions and align them per the compatibility matrix (often upgrading the driver resolves response-shape mismatches).
2. Run db.runCommand({ validate: 'collName' }) directly to inspect the raw response shape.
3. If the shape genuinely changed upstream, file a driver issue.
4. Catch MongoUnexpectedServerResponseError around validation tooling so a mismatched response doesn't abort the whole job.

try {
  const res = await db.admin().validateCollection(name);
} catch (e) {
  if (e instanceof MongoUnexpectedServerResponseError && /validation data/.test(e.message)) {
    // run db.runCommand({ validate: name }) to inspect the raw response shape; align driver/server versions
  }
  throw e;
}

When it happens

Trigger: Calling db.admin().validateCollection(name) (or collection-level validate) against a server whose validate response uses a different schema for the result field - e.g., a newer server returning a structured object instead of a string, or a non-standard build.

Common situations: Driver/server version skew where validate's response format changed; managed-service customized responses; running an older driver against a newer server.

Related errors

• Illegal profiling level value ${was}
• Error with profile command
• Driver attempted to initialize in load balancing mode, but t
• Current topology does not support sessions
• BSON element "${name}" is missing

AI-assisted analysis of mongodb/node-mongodb-native@3366c21a63 (2026-08-04). Data as JSON: /data/errors/7cfb151abc478f64.json. Report an issue: GitHub.