quarkusio/quarkus · error · IllegalArgumentException

Unknown ExtensionDependency type: ${dependency.getClass().ge

Error message

Unknown ExtensionDependency type: ${dependency.getClass().getName()}

What it means

createDeploymentDependency converts an ExtensionDependency into the actual Gradle Dependency to add to a deployment configuration. It handles exactly two subtypes: ProjectExtensionDependency and ArtifactExtensionDependency. Any other subclass hits the final throw, an IllegalArgumentException naming the concrete class. Since ExtensionDependency is internal tooling API, this indicates a new/unknown subtype introduced by a version mismatch or custom fork, or an unexpected object passed into the API.

Source

Thrown at devtools/gradle/gradle-model/src/main/java/io/quarkus/gradle/tooling/dependency/DependencyUtils.java:363

        return list;
    }

    public static Dependency create(DependencyHandler dependencies, String conditionalDependency) {
        final ArtifactCoords dependencyCoords = ArtifactCoords.fromString(conditionalDependency);
        return dependencies.create(String.join(":", dependencyCoords.getGroupId(), dependencyCoords.getArtifactId(),
                dependencyCoords.getVersion()));
    }

    public static Dependency createDeploymentDependency(
            DependencyHandler dependencyHandler,
            ExtensionDependency<?> dependency) {
        if (dependency instanceof ProjectExtensionDependency ped) {
            return createDeploymentProjectDependency(dependencyHandler, ped);
        } else if (dependency instanceof ArtifactExtensionDependency aed) {
            return createArtifactDeploymentDependency(dependencyHandler, aed);
        }

        throw new IllegalArgumentException("Unknown ExtensionDependency type: " + dependency.getClass().getName());
    }

    private static Dependency createDeploymentProjectDependency(DependencyHandler handler, ProjectExtensionDependency ped) {
        if (ped.isIncludedBuild()) {
            return new DefaultExternalModuleDependency(
                    ped.getDeploymentModule().getGroup().toString(),
                    ped.getDeploymentModule().getName(),
                    ped.getDeploymentModule().getVersion().toString());
        } else {
            return handler.create(handler.project(Map.of("path", ped.getDeploymentModule().getPath())));
        }
    }

    private static Dependency createArtifactDeploymentDependency(DependencyHandler handler,
            ArtifactExtensionDependency dependency) {
        return handler.create(dependency.getDeploymentModule().getGroupId() + ":"
                + dependency.getDeploymentModule().getArtifactId() + ":"
                + dependency.getDeploymentModule().getVersion());

View on GitHub (pinned to e1c734241f)

Solutions

1. Align all Quarkus Gradle plugin artifacts to one version (./gradlew build with a single plugin version) to eliminate duplicate ExtensionDependency classes
2. Check buildscript/classpath for multiple quarkus-gradle-model versions (./gradlew buildEnvironment) and exclude stale ones
3. If you authored a custom subtype, extend createDeploymentDependency to handle it or convert it to one of the supported types
4. Stop the daemon and clear configuration cache to drop stale plugin classes
5. If it occurs with unmodified releases, report to Quarkus with the class name from the message

Example fix

// before (custom subtype)
class MyExtDependency implements ExtensionDependency<MyCfg> { ... }
createDeploymentDependency(handler, new MyExtDependency(...));
// after (convert to supported type)
ProjectExtensionDependency ped = toProjectExtensionDependency(myDep);
createDeploymentDependency(handler, ped);

if (!(dependency instanceof ProjectExtensionDependency) && !(dependency instanceof ArtifactExtensionDependency)) {
    throw new IllegalStateException("Unsupported ExtensionDependency: " + dependency.getClass().getName());
}

static boolean supported(ExtensionDependency<?> d) {
    return d instanceof ProjectExtensionDependency || d instanceof ArtifactExtensionDependency;
}

try {
    Dependency dep = DependencyUtils.createDeploymentDependency(handler, extDep);
} catch (IllegalArgumentException e) {
    if (e.getMessage().startsWith("Unknown ExtensionDependency type:")) {
        // convert/handle the custom subtype before retrying
    } else throw e;
}

When it happens

Trigger: Calling DependencyUtils.createDeploymentDependency(handler, dependency) with an ExtensionDependency instance that is neither ProjectExtensionDependency nor ArtifactExtensionDependency — e.g. a custom subclass or one produced by a differently-versioned gradle-model class.

Common situations: Mixing Quarkus Gradle plugin module versions (gradle-model vs plugin) so two different ExtensionDependency class hierarchies exist on the classpath; custom IDE tooling constructing its own ExtensionDependency implementation; forks that added a third subtype without updating this switch.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• both extensionConfiguration and extensionDescriptor are null
• Quarkus Extension Dependency Verification Error. See logs be
• Unexpected mode:
• Cannot find deployment project for extension ${extensionArti
• Cannot find deployment project for extension ${extensionArti

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/219c1fee17f51133. Report an issue: GitHub.