quarkusio/quarkus · error · GradleException

Failed to configure ${taskPath}: sourceSet ${sourceSet} has

Error message

Failed to configure ${taskPath}: sourceSet ${sourceSet} has no output

What it means

configureGenerateCodeTask throws GradleException when the source set backing Quarkus code generation produces no output directory matching the generate-sources directory name, so the generateCode task cannot be wired up.

Source

Thrown at devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/QuarkusPlugin.java:687

                .cachingRelevantProperties(quarkusExt.getCachingRelevantProperties().get()));
        task.getJarEnabled().set(quarkusExt.packageConfig().jar().enabled());
        task.getNativeEnabled().set(quarkusExt.nativeConfig().enabled());
        task.getNativeSourcesOnly().set(quarkusExt.nativeConfig().sourcesOnly());
        task.getRunnerSuffix().set(quarkusExt.packageConfig().computedRunnerSuffix());
        task.getRunnerName().set(quarkusExt.packageConfig().outputName());
        task.getOutputDirectory().set(quarkusExt.packageConfig().outputDirectory());
        task.getJarType().set(quarkusExt.packageConfig().jar().type());
        task.getManifestAttributes().set(quarkusExt.manifest().getAttributes());
        task.getManifestSections().set(quarkusExt.manifest().getSections());
    }

    private static void configureGenerateCodeTask(QuarkusGenerateCode task,
            TaskProvider<QuarkusApplicationModelTask> applicationModelTaskTaskProvider, String generateSourcesDir,
            QuarkusPluginExtension quarkusExt) {
        SourceSet generatedSources = getSourceSet(task.getProject(), generateSourcesDir);
        Set<File> sourceSetOutput = generatedSources.getOutput().filter(f -> f.getName().equals(generateSourcesDir)).getFiles();
        if (sourceSetOutput.isEmpty()) {
            throw new GradleException("Failed to configure " + task.getPath() + ": sourceSet " + generateSourcesDir
                    + " has no output");
        }
        task.getApplicationModel()
                .set(applicationModelTaskTaskProvider.flatMap(QuarkusApplicationModelTask::getApplicationModel));
        task.getGeneratedOutputDirectory().set(generatedSources.getJava().getClassesDirectory());
        task.getCachingRelevantInput()
                .set(quarkusExt.cachingRelevantProperties(quarkusExt.getCachingRelevantProperties().get()));
        task.getManifestAttributes().set(quarkusExt.manifest().getAttributes());
        task.getManifestSections().set(quarkusExt.manifest().getSections());
    }

    private void createSourceSets(Project project) {
        SourceSetContainer sourceSets = project.getExtensions().getByType(SourceSetContainer.class);
        sourceSets.create(INTEGRATION_TEST_SOURCE_SET_NAME);
        sourceSets.create(NATIVE_TEST_SOURCE_SET_NAME);
        sourceSets.create(QuarkusGenerateCode.QUARKUS_GENERATED_SOURCES);
        sourceSets.create(QuarkusGenerateCode.QUARKUS_TEST_GENERATED_SOURCES);
    }

View on GitHub (pinned to e1c734241f)

Solutions

1. Do not remove or rename the generated-sources source set created by the Quarkus plugin
2. Verify sourceSets configuration keeps the generated sources output (sourceSets { main { ... } } customizations must not delete it)
3. Check quarkusExt settings / generateSourcesDir value matches the actual source set name

Example fix

// before (custom build logic)
sourceSets.removeIf { it.name == "quarkusGeneratedSources" }
// after
// keep the source set; only append extra srcDirs
sourceSets.matching { it.name == "quarkusGeneratedSources" }.configureEach {
    java.srcDir("extra-generated")
}

Set<File> out = project.getExtensions().getByType(SourceSetContainer.class)
    .getByName("quarkusGeneratedSources").getOutput().getFiles();
if (out.isEmpty()) { throw new IllegalStateException("generated sources source set has no output"); }

try { /* build */ } catch (GradleException e) { if (e.getMessage().contains("has no output")) { /* restore source set config */ } }

When it happens

Trigger: Registering/configuring a QuarkusGenerateCode task where getSourceSet(project, generateSourcesDir).getOutput() yields no File named generateSourcesDir — typically when the generated-sources source set was removed, renamed, or not created by the plugin extension.

Common situations: Custom build logic overriding or removing the 'quarkusGeneratedSources'-style source set; source set output reconfigured (custom classes dirs); applying the Quarkus plugin to a project with heavily customized source set layout.

Related errors

• because the project does not have any source set / among the
• Failed to load CodeGenProvider class from deployment classlo
• Failed to load application configuration
• Failed to create output directory for generated sources: %s
• Failed to resolve ${appArtifact}

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/cd1b66ff697720f1. Report an issue: GitHub.