Fix Gradle 9 implicit dependency for compileJava9Java

Gradle 9 detects that compileJava9Java uses mainSourceSet.output
which includes copyExternalLibs destination. Add explicit dependency.

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jbachorik

build-logic/conventions/src/main/kotlin/com/datadoghq/profiler/ProfilerTestPlugin.kt

@@ -122,8 +122,11 @@ class ProfilerTestPlugin : Plugin<Project> {
     private fun configureJavaExecTask(task: JavaExec, extension: ProfilerTestExtension, project: Project) {
         // Disable Gradle 9 toolchain probing (fails on musl with glibc probe binary)
         // Use explicit executable path instead
+        // Note: Must clear convention AND set value to prevent toolchain resolution
         @Suppress("NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS")
-        task.javaLauncher.set(null as org.gradle.jvm.toolchain.JavaLauncher?)
+        task.javaLauncher.convention(null as org.gradle.jvm.toolchain.JavaLauncher?)
+        @Suppress("NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS")
+        task.javaLauncher.value(null as org.gradle.jvm.toolchain.JavaLauncher?)
         task.setExecutable(PlatformUtils.testJavaExecutable())
 
         // JVM arguments for JavaExec tasks

ddprof-lib/build.gradle.kts

@@ -85,6 +85,14 @@ val copyExternalLibs by tasks.registering(Copy::class) {
   }
 }
 
+// Gradle 9 requires explicit dependency: compileJava9Java uses mainSourceSet.output
+// which includes the copyExternalLibs destination directory
+afterEvaluate {
+  tasks.named("compileJava9Java") {
+    dependsOn(copyExternalLibs)
+  }
+}
+
 // Create JAR tasks for each build configuration using nativeBuild extension utilities
 // Uses afterEvaluate to discover configurations dynamically from NativeBuildExtension
 afterEvaluate {