My ultimate goal is to find the number of partitions for a Pulsar topic (Getting number of partitions of a Pulsar topic: could not be parsed into a proper Uri, missing scheme) but in the process of an alternative method, encountered something peculiar.

I have a hack where I loop up through the max number of partitions and keep trying to create a reader until an error happens.

        for (i in 0..MAX_NUM_PARTITIONS) {
            val topicPartition = "$topic-partition-$i"
            var partitionReader: Reader<ByteArray>? = null
            try {
                partitionReader =
                    client
                        .newReader(BYTES)
                        .startMessageId(MessageId.latest)
                        .topic(topicPartition)
                        .create()
            } catch (e: Exception) {
                // TODO: This still prints a CompletionException error to the console unnecessarily.
                // Either catch that or calculate # partitions in a cleaner way.
                break
            }

            if (partitionReader != null) {
                readers.add(partitionReader)
            }
        }

java.util.concurrent.CompletionException:
org.apache.pulsar.client.api.PulsarClientException$NotAllowedException:
{“errorMsg”:”Illegal topic partition name …

I would like to catch the exception above and not have it print to the console. Despite the try-catch above, it still prints. Why? Is this a Kotlin coroutine related phenomenon? The code does run in a suspend function.