NullPointerException in QuarkusPluginExtension.beforeTest with Configuration Cache Enabled

[shreyasahir]

Describe the bug

When running tests with the Quarkus Gradle plugin and Gradle’s configuration cache enabled, a NullPointerException occurs because the project field in io.quarkus.gradle.extension.QuarkusPluginExtension is null. This happens during the beforeTest method, which attempts to build an application model via ApplicationDeploymentClasspathBuilder, calling project.getPath() on a null project reference. The issue persists even when marking Quarkus tasks (except :test) as notCompatibleWithConfigurationCache, suggesting a deeper initialization problem in the plugin’s test setup.

Expected behavior

Test should run when org.gradle.configuration-cache=true

Actual behavior

This breaks test execution (e.g., ./gradlew :shopper-profile-api-controller:test), preventing JUnit 5/Kotest tests from running. Disabling the configuration cache (org.gradle.configuration-cache=false) resolves the issue, but we’d like to use the cache for build performance (targeting <20-30s Configuration time). Updating the Quarkus plugin version or tweaking test properties (e.g., quarkus.test.native-image=false) didn’t help.

How to Reproduce?

Steps to Reproduce:

• Use a multi-module Gradle project with Quarkus, Kotlin, and JUnit 5/Kotest.
• Enable org.gradle.configuration-cache=true in gradle.properties.
• Configure a simple failing test (e.g., assertEquals(1, 2)).
• Run ./gradlew :shopper-profile-api-controller:test --configuration-cache --info --stacktrace.
• Observe the NPE.

Output of uname -a or ver

Darwin LM-SJN-40042039 23.6.0 Darwin Kernel Version 23.6.0: Thu Dec 19 20:47:16 PST 2024; root:xnu-10063.141.1.703.2~1/RELEASE_ARM64_T6031 arm64

Output of java -version

JVM 21

Quarkus version or git rev

3.16.4

Build tool (ie. output of mvnw --version or gradlew --version)

gradle 8.11.1

Additional information

Caused by: java.lang.NullPointerException: Cannot invoke "org.gradle.api.Project.getPath()" because "project" is null
at io.quarkus.gradle.dependency.ApplicationDeploymentClasspathBuilder.(ApplicationDeploymentClasspathBuilder.java:151)
at io.quarkus.gradle.tooling.GradleApplicationModelBuilder.buildAll(GradleApplicationModelBuilder.java:102)
at io.quarkus.gradle.tooling.ToolingUtils.create(ToolingUtils.java:186)
at io.quarkus.gradle.tooling.ToolingUtils.create(ToolingUtils.java:182)
at io.quarkus.gradle.extension.QuarkusPluginExtension.getApplicationModel(QuarkusPluginExtension.java:198)
at io.quarkus.gradle.extension.QuarkusPluginExtension.beforeTest(QuarkusPluginExtension.java:75)

[quarkus-bot]

/cc @geoand (kotlin), @gwenneg (cache), @radcortez (config)

[geoand]

cc @quarkusio/devtools

[aloubyansky]

I'm wondering whether the following would fix it

diff --git a/devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/extension/QuarkusPluginExtension.java b/devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/extension/QuarkusPluginExtension.java
index cbf5e6e62e..d9b8f13fb1 100644
--- a/devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/extension/QuarkusPluginExtension.java
+++ b/devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/extension/QuarkusPluginExtension.java
@@ -72,7 +72,7 @@ public void manifest(Action<Manifest> action) {
     public void beforeTest(Test task) {
         try {
             Map<String, Object> props = task.getSystemProperties();
-            ApplicationModel appModel = getApplicationModel(TEST);
+            ApplicationModel appModel = ToolingUtils.create(task.getProject(), TEST);

@shreyasahir is there a chance you could test that or provide a reproducer for me to test? Thanks.