Keep svmjunit separate from libjvm state

Author: dougxc

substratevm/AGENTS.md

@@ -27,3 +27,6 @@ Do not run `mx` commands concurrently; parallel runs can produce misleading fail
 
 - If you touch documented behavior, update `docs/`.
 - Do not commit generated output from `mxbuild/`, `svmbuild/`, `graal_dumps/`, or `sources/`.
+- Be careful when changing `mx native-unittest` / `svmjunit` feature registration. Features added to the shared native test image affect unrelated tests too.
+- Do not register production ImageSingletons or other global runtime markers from shared `svmjunit` test features. In particular, avoid making the shared test image look like a different product or launch mode, such as a `libjvm` image.
+- If a test needs product-specific global state, prefer a targeted image or test-specific setup over adding that state to the global native-unit-test feature list in `mx.substratevm/mx_substratevm.py`.

substratevm/mx.substratevm/mx_substratevm.py

@@ -392,8 +392,11 @@ def native_image_func(args, **kwargs):
     yield native_image_func
 
 native_image_context.hosted_assertions = ['-J-ea', '-J-esa']
+# Features added here are loaded into the shared `svmjunit` image used by unrelated native unit
+# tests as well. Keep them limited to generic test support; do not register product-specific global
+# state or ImageSingleton markers here (for example anything that makes `svmjunit` look like a
+# `libjvm` image).
 _native_unittest_features = '--features=' + ','.join(('com.oracle.svm.test.ImageInfoTest$TestFeature',
-                                                      'com.oracle.svm.test.LibJVMLauncherOptionTest$TestFeature',
                                                       'com.oracle.svm.test.services.ServiceLoaderTest$TestFeature',
                                                       'com.oracle.svm.test.services.SecurityServiceTest$TestFeature',
                                                       'com.oracle.svm.test.ReflectionRegistrationTest$TestFeature',

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/LibJVMLauncherOptionTest.java

@@ -40,14 +40,11 @@
 import java.util.Set;
 
 import org.graalvm.nativeimage.ImageInfo;
-import org.graalvm.nativeimage.ImageSingletons;
-import org.graalvm.nativeimage.hosted.Feature;
 import org.junit.Assert;
 import org.junit.Assume;
 import org.junit.Test;
 
 import com.oracle.svm.core.jdk.RuntimeBootModuleLayerSupport;
-import com.oracle.svm.core.libjvm.LibJVMMainMethodWrappers;
 import com.oracle.svm.core.properties.RuntimeSystemPropertyParser;
 
 /// Regression tests for `libjvm` launcher option handling in native unit tests.
@@ -61,15 +58,6 @@ public class LibJVMLauncherOptionTest {
 
     private static final String MISSING_MODULE_NAME = "com.oracle.svm.test.missing.module";
 
-    public static class TestFeature implements Feature {
-        @Override
-        public void afterRegistration(AfterRegistrationAccess access) {
-            if (!ImageSingletons.contains(LibJVMMainMethodWrappers.class)) {
-                ImageSingletons.add(LibJVMMainMethodWrappers.class, new LibJVMMainMethodWrappers());
-            }
-        }
-    }
-
     /// Verifies that runtime parsing consumes only the JVM-level `--module-path=...` and
     /// `--add-modules=...` forms, leaving launcher-handled variants untouched.
     @Test
@@ -181,7 +169,6 @@ public void bootLayerRootModuleComputationExpandsAndDeduplicates() throws Except
 
     private static void assumeLibJVMNativeImage() {
         Assume.assumeTrue(ImageInfo.inImageCode());
-        Assume.assumeTrue(ImageSingletons.contains(LibJVMMainMethodWrappers.class));
     }
 
     private static void invokeRuntimeBootLayerInitialize() throws Exception {