quarkusio/quarkus · error · IllegalArgumentException

Expected a value of type ${type.getName()} for option ${name

Error message

Expected a value of type ${type.getName()} for option ${name} but got ${o} of type ${o.getClass().getName()}

What it means

RegistryExtensionResolver.getExtraConfigOption() reads a free-form value from the registry config 'extra' map and casts it to the expected type. If the configured value's runtime type differs from the expected Class (e.g. an Integer where a String is expected), an IllegalArgumentException is thrown naming the option, expected type, value, and actual type.

Source

Thrown at independent-projects/tools/registry-client/src/main/java/io/quarkus/registry/RegistryExtensionResolver.java:56

     * Returns an extra config option value with an expected type.
     * If an option was not configured, the returned value will be null.
     * If the configured value cannot be cast to an expected type, the method will throw an error.
     *
     * @param config registry configuration
     * @param name option name
     * @param type expected value type
     * @return configured value or null
     * @param <T> expected value type
     */
    private static <T> T getExtraConfigOption(RegistryConfig config, String name, Class<T> type) {
        Object o = config.getExtra().get(name);
        if (o == null) {
            return null;
        }
        if (type.isInstance(o)) {
            return (T) o;
        }
        throw new IllegalArgumentException(
                "Expected a value of type " + type.getName() + " for option " + name + " but got " + o
                        + " of type " + o.getClass().getName());
    }

    /**
     * Returns offering configured by the user in the registry configuration or null, in case
     * no offering was configured.
     *
     * An offering would be the name part of the {@code <name>-support} in the extension metadata.
     *
     * @param config registry configuration
     * @return user configured offering or null
     */
    private static String getConfiguredOfferingOrNull(RegistryConfig config) {
        var offering = getExtraConfigOption(config, OFFERING, String.class);
        return offering == null || offering.isBlank() ? null : offering;
    }

View on GitHub (pinned to e1c734241f)

Solutions

Quote the value in the config file so it parses as the expected type (e.g. offering: "my-offering").
Inspect the actual type named in the message and convert the configured value to that type.
When building RegistryConfig programmatically, put correctly-typed values into extra (String for offering, String stream IDs for recommend-streams-starting).
Wrap the resolver construction in a try-catch and validate the extra map types before use.

Example fix

// before (.quarkus/config.yaml)
extra:
  offering: 12345      # parsed as Integer -> IllegalArgumentException
// after
extra:
  offering: "12345"    # quoted, parsed as String

Defensive patterns

Strategy: validation

Validate before calling

// Java
Object offering = registryConfig.getExtra().get("offering");
if (offering != null && !(offering instanceof String)) {
    throw new IllegalArgumentException("offering must be a quoted string, got: " + offering.getClass());
}

Type guard

// Java
static <T> T asTypeOrNull(Map<String, Object> extra, String name, Class<T> type) {
    Object o = extra.get(name);
    return type.isInstance(o) ? type.cast(o) : null; // avoids the throw
}

Try / catch

// Java
try {
    resolver = ExtensionCatalogResolver.builder().setConfig(config).build();
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("Expected a value of type")) {
        logger.error("Fix registry config extra types: " + e.getMessage());
    }
    throw e;
}

Prevention

Always quote string-ish values in .quarkus/config.yaml (offering: "value").
Remember YAML parsers turn unquoted 123 into Integer and true into Boolean.
When constructing RegistryConfig in code, use the exact expected Java types.
Add a startup config sanity-check that validates extra option types.

When it happens

Trigger: RegistryConfig.extra containing option 'offering' (expected String) or 'recommend-streams-starting' boundaries (expected String values) typed as a number/boolean/Map because of YAML/JSON type inference, accessed via getConfiguredOfferingOrNull() or recommendStreamsStarting().

Common situations: In YAML, writing offering: 123 (parsed as Integer) instead of offering: "123"; quoting mistakes or programmatic RegistryConfig construction with wrong Java types in the extra map.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/335ed46f4d901224. Report an issue: GitHub.