Admin `listTopics` incorrect type

[Vilsol]

In TS the defined return type of Admin listTopics is string[].

In reality, the returned type is an object with a bunch of other stuff, which looks awfully similar to the ClusterMetadata.

Lib version: 1.11.0
Kafka version: 3.9.0

[mcollina]

Looks like a bug! How are you deploying kafka? Can you provide a complete reproduction? That logic is passing our test:

kafka/test/clients/admin/admin.test.ts

Line 160 in fbb3919

topics = await admin.listTopics()

[Vilsol]

@mcollina I have stripped down the sample code to its bare essentials: https://github.com/Vilsol/kafka-listtopics-bug

Here is a run of that code: https://github.com/Vilsol/kafka-listtopics-bug/actions/runs/17175243950/job/48730254109

Making this demo made me uncover that it's not just returning the metadata response, but it seems to be random.

You can see that in the test logs:

The Admin is ready.
listTopics() = {
  id: 'sHbt4L5CRgmAa3AtFsAqTA',
  brokers: Map(1) { 1 => { host: 'localhost', port: 29092 } },
  topics: Map(0) {},
  lastUpdate: 1755950853730
}
Topic 59b2f76095d5ff4d10be5eaf2bd23a903a29955a created successfully
listTopics() = [ '59b2f76095d5ff4d10be5eaf2bd23a903a29955a' ]
Topic 59b2f76095d5ff4d10be5eaf2bd23a903a29955a already exists
The Admin is ready.
listTopics() = {
  id: 'sHbt4L5CRgmAa3AtFsAqTA',
  brokers: Map(1) { 1 => { host: 'localhost', port: 29092 } },
  topics: Map(0) {},
  lastUpdate: 1755950853806
}
Cannot create topic 59b2f76095d5ff4d10be5eaf2bd23a903a29955a: {
  throttleTimeMs: 0,
  topics: [
    {
      name: '59b2f76095d5ff4d10be5eaf2bd23a903a29955a',
      topicId: '00000000-0000-0000-0000-000000000000',
      errorCode: 36,
      errorMessage: "Topic '59b2f76095d5ff4d10be5eaf2bd23a903a29955a' already exists.",
      numPartitions: -1,
      replicationFactor: -1,
      configs: []
    }
  ]
}