projectlombok/lombok · error · IllegalArgumentException

There is more than one parameter definition that includes…

Error message

There is more than one parameter definition that includes TOPIC: 

What it means

While parsing a custom logger declaration, each parameter definition list is classified as including TOPIC or not. At most one list may include TOPIC; a second one throws IllegalArgumentException naming both conflicting lists.

Solutions

1. Keep at most one parameter list containing TOPIC; move optional extras (TYPE) into the other list or remove duplicates.
2. Express overload variety via the non-TOPIC lists only.
3. Validate the declaration against the pattern before saving it to lombok.config.

Example fix

// before
lombok.log.customDeclaration = com.acme.F.create(TOPIC)(TOPIC,TYPE)
// after
lombok.log.customDeclaration = com.acme.F.create(TOPIC)(TYPE)

int topicLists = 0;
// for each parenthesized param group: if (group.contains("TOPIC")) topicLists++;
boolean valid = topicLists <= 1;

try {
  LogDeclaration decl = LogDeclaration.valueOf(cfgValue);
} catch (IllegalArgumentException e) {
  // reduce duplicate TOPIC groups and retry once
}

When it happens

Trigger: LogDeclaration.valueOf with a declaration whose parameter section contains two or more alternative parameter lists that each include TOPIC, e.g. 'create(TOPIC)(TOPIC, TYPE)' — the pattern's parenthesized groups separated by '|'.

Common situations: Writing multi-signature custom logger declarations where several overloads accidentally all declare TOPIC, instead of varying only the non-topic part.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

• The declaration must follow the pattern: [LoggerType…
• There is more than one parmaeter definition that does not…
• No logger factory method parameters specified.
• Minor version must be between 0 and 999
• Lombok supports at most v

AI-assisted analysis of projectlombok/lombok@6d6a3e9fec (2026-09-07). Data as JSON: /api/errors/7fb8a931cbab1281. Report an issue: GitHub.

Appendix: source

Thrown at src/core/lombok/core/configuration/LogDeclaration.java:67

	}
	
	public static LogDeclaration valueOf(String declaration) {
		if (declaration == null) return null;
		
		Matcher matcher = DECLARATION_PATTERN.matcher(declaration);
		if (!matcher.matches()) throw new IllegalArgumentException("The declaration must follow the pattern: [LoggerType ]LoggerFactoryType.loggerFactoryMethod(loggerFactoryMethodParams)[(loggerFactoryMethodParams)]");
		
		TypeName loggerFactoryType = TypeName.valueOf(matcher.group(2));
		TypeName loggerType = TypeName.valueOf(matcher.group(1));
		if (loggerType == null) loggerType = loggerFactoryType;
		IdentifierName loggerFactoryMethod = IdentifierName.valueOf(matcher.group(3));
		List<List<LogFactoryParameter>> allParameters = parseParameters(matcher.group(4));
		
		List<LogFactoryParameter> parametersWithoutTopic = null;
		List<LogFactoryParameter> parametersWithTopic = null;
		for (List<LogFactoryParameter> parameters: allParameters) {
			if (parameters.contains(LogFactoryParameter.TOPIC)) {
				if (parametersWithTopic != null) throw new IllegalArgumentException("There is more than one parameter definition that includes TOPIC: " + parametersWithTopic + " and " + parameters);
				parametersWithTopic = parameters;
			} else {
				if (parametersWithoutTopic != null) throw new IllegalArgumentException("There is more than one parmaeter definition that does not include TOPIC: " + parametersWithoutTopic + " and " + parameters);
				parametersWithoutTopic = parameters;
			}
		}
		
		// sanity check (the pattern should disallow this situation
		if (parametersWithoutTopic == null && parametersWithTopic == null) throw new IllegalArgumentException("No logger factory method parameters specified.");
		
		return new LogDeclaration(loggerType, loggerFactoryType, loggerFactoryMethod, parametersWithoutTopic, parametersWithTopic);
	}
	
	private static List<List<LogFactoryParameter>> parseParameters(String parametersDefinitions) {
		List<List<LogFactoryParameter>> allParameters = new ArrayList<List<LogFactoryParameter>>();
		Matcher matcher = PARAMETERS_PATTERN.matcher(parametersDefinitions);
		while (matcher.find()) {
			String parametersDefinition = matcher.group(1);

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