Gradle: ability to disable worker process isolation, pass all envs+sys-props

devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/tasks/QuarkusBuildTask.java

@@ -163,9 +163,7 @@ void generateBuild() {
                             .collect(Collectors.joining("\n    ", "\n    ", "")));
         }
 
-        WorkQueue workQueue = getWorkerExecutor()
-                .processIsolation(processWorkerSpec -> configureProcessWorkerSpec(processWorkerSpec, effectiveConfig,
-                        extension().buildForkOptions));
+        WorkQueue workQueue = workQueue(effectiveConfig, () -> extension().buildForkOptions);
 
         workQueue.submit(BuildWorker.class, params -> {
             params.getBuildSystemProperties().putAll(effectiveConfig.configMap());

devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/tasks/QuarkusGenerateCode.java

@@ -104,9 +104,7 @@ public void generateCode() {
         getLogger().debug("Will trigger preparing sources for source directory: {} buildDir: {}",
                 sourcesDirectories, getProject().getBuildDir().getAbsolutePath());
 
-        WorkQueue workQueue = getWorkerExecutor()
-                .processIsolation(processWorkerSpec -> configureProcessWorkerSpec(processWorkerSpec, effectiveConfig,
-                        extension().codeGenForkOptions));
+        WorkQueue workQueue = workQueue(effectiveConfig, () -> extension().codeGenForkOptions);
 
         workQueue.submit(CodeGenWorker.class, params -> {
             params.getBuildSystemProperties().putAll(effectiveConfig.configMap());

devtools/gradle/gradle-application-plugin/src/main/java/io/quarkus/gradle/tasks/QuarkusTask.java

@@ -4,13 +4,15 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.List;
+import java.util.function.Supplier;
 
 import javax.inject.Inject;
 
 import org.gradle.api.Action;
 import org.gradle.api.DefaultTask;
 import org.gradle.process.JavaForkOptions;
 import org.gradle.workers.ProcessWorkerSpec;
+import org.gradle.workers.WorkQueue;
 import org.gradle.workers.WorkerExecutor;
 
 import io.quarkus.gradle.extension.QuarkusPluginExtension;
@@ -35,12 +37,34 @@ QuarkusPluginExtension extension() {
         return extension;
     }
 
-    void configureProcessWorkerSpec(ProcessWorkerSpec processWorkerSpec, EffectiveConfig effectiveConfig,
+    WorkQueue workQueue(EffectiveConfig effectiveConfig, Supplier<List<Action<? super JavaForkOptions>>> forkOptionsActions) {
+        WorkerExecutor workerExecutor = getWorkerExecutor();
+
+        // Use process isolation by default, unless Gradle's started with its debugging system property or the
+        // system property `quarkus.gradle-worker.no-process is set to `true`.
+        if (Boolean.getBoolean("org.gradle.debug") || Boolean.getBoolean("quarkus.gradle-worker.no-process")) {
+            return workerExecutor.classLoaderIsolation();
+        }
+
+        return workerExecutor.processIsolation(processWorkerSpec -> configureProcessWorkerSpec(processWorkerSpec,
+                effectiveConfig, forkOptionsActions.get()));
+    }
+
+    private void configureProcessWorkerSpec(ProcessWorkerSpec processWorkerSpec, EffectiveConfig effectiveConfig,
             List<Action<? super JavaForkOptions>> customizations) {
         JavaForkOptions forkOptions = processWorkerSpec.getForkOptions();
 
         customizations.forEach(a -> a.execute(forkOptions));
 
+        // Pass all system properties
+        System.getProperties().forEach((k, v) -> {
+            String key = k.toString();
+            forkOptions.systemProperty(key, v);
+        });
+
+        // Pass all environment variables
+        forkOptions.environment(System.getenv());
+
         if (OS.determineOS() == OS.WINDOWS) {
             // On Windows, gRPC code generation is sometimes(?) unable to find "java.exe". Feels (not proven) that
             // the grpc code generation tool looks up "java.exe" instead of consulting the 'JAVA_HOME' environment.