OpenAPITools/openapi-generator · error · IllegalArgumentException

clientRegistrationId requires useSpringBoot4=true because…

Error message

clientRegistrationId requires useSpringBoot4=true because @ClientRegistrationId is provided by Spring Security 7

What it means

Thrown by the Spring generator's option processing when clientRegistrationId is set but useSpringBoot4 is not enabled. The generated HTTP-interface client code relies on @ClientRegistrationId, an annotation introduced with Spring Security 7, which ships only with Spring Boot 4. The generator refuses to emit code that would not compile against older Spring Boot versions.

Solutions

Add -DuseSpringBoot4=true (or <useSpringBoot4>true</useSpringBoot4> in the Maven/Gradle plugin config) whenever clientRegistrationId is set.
Keep --library=spring-http-interface; clientRegistrationId is rejected by every other library.
If you must stay on Spring Boot 3, remove clientRegistrationId and register the OAuth2 ClientRegistration in your own Spring configuration.

Example fix

# before
openapi-generator generate -g spring -i api.yaml --library=spring-http-interface -DclientRegistrationId=okta

# after
openapi-generator generate -g spring -i api.yaml --library=spring-http-interface -DclientRegistrationId=okta -DuseSpringBoot4=true

Defensive patterns

Strategy: validation

Validate before calling

# bash: assert option pairing before invoking the generator
if [ -n "$CLIENT_REGISTRATION_ID" ] && [ "$USE_SPRING_BOOT4" != "true" ]; then
  echo "clientRegistrationId requires useSpringBoot4=true" >&2; exit 1
fi
openapi-generator generate -g spring --library=spring-http-interface \
  -DclientRegistrationId=$CLIENT_REGISTRATION_ID -DuseSpringBoot4=$USE_SPRING_BOOT4

Try / catch

// Java (programmatic use)
try {
    opts.put("clientRegistrationId", "okta");
    opts.put("useSpringBoot4", true);
    new DefaultGenerator().opts(clientOptInput).generate();
} catch (IllegalArgumentException e) {
    // option-conflict messages from processOpts(); log and fix config, do not retry
    throw new GenerationConfigException("Invalid spring options: " + e.getMessage(), e);
}

Prevention

Keep one versioned, reviewed generator options file per project instead of ad-hoc CLI flags.
Treat clientRegistrationId as a Boot-4-only feature and document it next to the option.
Fail fast in CI: run generation on every spec change so option conflicts surface immediately.

When it happens

Trigger: Run openapi-generator (CLI, Maven or Gradle plugin) with -g spring, --library=spring-http-interface and -DclientRegistrationId=<id> but without -DuseSpringBoot4=true. This specific message appears only after the library check passed, i.e. library is spring-http-interface.

Common situations: Copying an OAuth2 client example that predates Spring Boot 4 support; enabling clientRegistrationId while keeping Boot 3 defaults; setting useSpringBoot3=true together with clientRegistrationId (the generator silently clears useSpringBoot3 when useSpringBoot4 is on, but not the reverse).

Related errors

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/4c6ce7906da0ff17. Report an issue: GitHub.

Appendix: source

Thrown at modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java:653

        convertPropertyToBooleanAndWriteBack(USE_SPRING_SECURITY_PRE_AUTHORIZE, this::setUseSpringSecurityPreAuthorize);
        convertPropertyToStringAndWriteBack(SPRING_SECURITY_AUTHORITY_PREFIX, this::setSpringSecurityAuthorityPrefix);

        additionalProperties.put("springHttpStatus", new SpringHttpStatusLambda());

        convertPropertyToBooleanAndWriteBack(USE_ENUM_CASE_INSENSITIVE, this::setUseEnumCaseInsensitive);
        convertPropertyToBooleanAndWriteBack(USE_JACKSON_3, this::setUseJackson3);
        convertPropertyToBooleanAndWriteBack(USE_SPRING_BOOT3, this::setUseSpringBoot3);
        convertPropertyToBooleanAndWriteBack(USE_SPRING_BOOT4, this::setUseSpringBoot4);

        if (isUseSpringBoot4()) {
            setUseSpringBoot3(false);
        }
        if (isNotEmpty(clientRegistrationId)) {
            if (!SPRING_HTTP_INTERFACE.equals(library)) {
                throw new IllegalArgumentException(CLIENT_REGISTRATION_ID + " is only supported with the " + SPRING_HTTP_INTERFACE + " library");
            }
            if (!isUseSpringBoot4()) {
                throw new IllegalArgumentException(CLIENT_REGISTRATION_ID + " requires " + USE_SPRING_BOOT4 + "=true because @ClientRegistrationId is provided by Spring Security 7");
            }
        }
        if (useSpringSecurityPreAuthorize && !SPRING_BOOT.equals(library)) {
            throw new IllegalArgumentException(USE_SPRING_SECURITY_PRE_AUTHORIZE
                    + " is only supported with the " + SPRING_BOOT + " library");
        }

        if (isUseSpringBoot3() || isUseSpringBoot4()) {
            if (AnnotationLibrary.SWAGGER1.equals(getAnnotationLibrary())) {
                throw new IllegalArgumentException(AnnotationLibrary.SWAGGER1.getPropertyName() + " is not supported with Spring Boot > 3.x");
            }
            useJakartaEe = true;
            applyJakartaPackage();
        }
        if(isUseJackson3() && !isUseSpringBoot4()){
            throw new IllegalArgumentException("useJackson3 is only available with Spring Boot >= 4");
        }
        if(this.useJackson3){

View on GitHub (pinned to fcec517be3)