apache/pulsar · error · IllegalArgumentException

isRegexPattern for input topic cannot be altered

Error message

isRegexPattern for input topic  cannot be altered

What it means

Thrown by SinkConfigUtils.validateUpdate when a known input topic's ConsumerConfig.isRegexPattern() flag differs between the existing and new config. Whether a topic is consumed as a regex pattern is fixed at creation time.

Source

Thrown at pulsar-functions/utils/src/main/java/org/apache/pulsar/functions/utils/SinkConfigUtils.java:677

            });
        }
        if (newConfig.getTopicToSchemaType() != null) {
            newConfig.getTopicToSchemaType().forEach((topicName, schemaClassname) -> {
                newConfig.getInputSpecs().put(topicName,
                        ConsumerConfig.builder()
                                .schemaType(schemaClassname)
                                .isRegexPattern(false)
                                .build());
            });
        }
        if (!newConfig.getInputSpecs().isEmpty()) {
            SinkConfig finalMergedConfig = mergedConfig;
            newConfig.getInputSpecs().forEach((topicName, consumerConfig) -> {
                if (!existingConfig.getInputSpecs().containsKey(topicName)) {
                    throw new IllegalArgumentException("Input Topics cannot be altered");
                }
                if (consumerConfig.isRegexPattern() != existingConfig.getInputSpecs().get(topicName).isRegexPattern()) {
                    throw new IllegalArgumentException(
                            "isRegexPattern for input topic " + topicName + " cannot be altered");
                }
                finalMergedConfig.getInputSpecs().put(topicName, consumerConfig);
            });
        }
        if (newConfig.getProcessingGuarantees() != null && !newConfig.getProcessingGuarantees()
                .equals(existingConfig.getProcessingGuarantees())) {
            throw new IllegalArgumentException("Processing Guarantees cannot be altered");
        }
        if (newConfig.getConfigs() != null) {
            mergedConfig.setConfigs(newConfig.getConfigs());
        }
        if (newConfig.getSecrets() != null) {
            mergedConfig.setSecrets(newConfig.getSecrets());
        }
        if (newConfig.getParallelism() != null) {
            mergedConfig.setParallelism(newConfig.getParallelism());
        }

View on GitHub (pinned to 820761864e)

Solutions

1. Keep isRegexPattern for each input topic identical to the existing sink's value
2. To change a topic between regex and plain, delete and recreate the sink
3. Compare each ConsumerConfig.isRegexPattern() with the deployed config before updating

Example fix

// before
cc.setRegexPattern(false); // existing sink had true
sinkConfig.getInputSpecs().put("persistent://public/default/.*", cc);
admin.sinks().updateSink(tenant, namespace, sinkConfig, null);
// after
cc.setRegexPattern(true); // match existing
sinkConfig.getInputSpecs().put("persistent://public/default/.*", cc);
admin.sinks().updateSink(tenant, namespace, sinkConfig, null);

newCfg.getInputSpecs().forEach((topic, cc) -> {
    ConsumerConfig old = existing.getInputSpecs().get(topic);
    if (old != null && cc.isRegexPattern() != old.isRegexPattern()) {
        throw new IllegalArgumentException("isRegexPattern mismatch for " + topic);
    }
});

try {
    admin.sinks().updateSink(tenant, namespace, cfg, null);
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("isRegexPattern")) { /* fix regex flag to match existing */ }
    else throw e;
}

When it happens

Trigger: Updating a sink whose inputSpecs entry for an existing topic flips isRegexPattern from true to false or vice versa; passing a plain topic name where the sink was created with a regex topic (or the reverse).

Common situations: Config migration changes topic declarations from regex 'persistent://public/default/.*' to explicit names; a serializer/tool rewrites topics and toggles the regex flag.

Related errors

• Sink Names differ
• Subscription Name cannot be altered
• Input Topics cannot be altered
• Processing Guarantees cannot be altered
• Retain Ordering cannot be altered

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/a76da524300c2f46. Report an issue: GitHub.