Add Java 26 support to CI Visibility

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/CiVisibilitySystem.java

@@ -18,6 +18,7 @@
 import datadog.trace.api.git.GitInfoProvider;
 import datadog.trace.bootstrap.ContextStore;
 import datadog.trace.bootstrap.instrumentation.api.AgentTracer;
+import datadog.trace.civisibility.compiler.CompilerModuleExporter;
 import datadog.trace.civisibility.config.ExecutionSettings;
 import datadog.trace.civisibility.config.JvmInfo;
 import datadog.trace.civisibility.coverage.file.instrumentation.CoverageClassTransformer;
@@ -75,6 +76,10 @@ public static void start(Instrumentation inst, SharedCommunicationObjects sco) {
 
     sco.createRemaining(config);
 
+    if (config.isCiVisibilityCompilerPluginAutoConfigurationEnabled()) {
+      inst.addTransformer(new CompilerModuleExporter(inst));
+    }
+
     CiVisibilityMetricCollector metricCollector =
         config.isCiVisibilityTelemetryEnabled()
             ? new CiVisibilityMetricCollectorImpl()

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/compiler/CompilerModuleExporter.java

@@ -0,0 +1,66 @@
+package datadog.trace.civisibility.compiler;
+
+import datadog.trace.util.JDK9ModuleAccess;
+import java.lang.instrument.ClassFileTransformer;
+import java.lang.instrument.Instrumentation;
+import java.security.ProtectionDomain;
+import java.util.Collections;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Exports jdk.compiler internal packages to the classloader that loads dd-javac-plugin.
+ *
+ * <p>On JDK 16+ (strong encapsulation), dd-javac-plugin's CompilerModuleOpener uses burningwave to
+ * export these packages. On JDK 26+, burningwave fails due to Unsafe restrictions (JEP 471/498).
+ * This transformer intercepts dd-javac-plugin class loading and does the export using
+ * Instrumentation.redefineModule() instead.
+ *
+ * <p>Each Maven compilation step (compile, testCompile) may use a different classloader, so we
+ * track which classloaders have already been exported to and re-export for new ones.
+ */
+public class CompilerModuleExporter implements ClassFileTransformer {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(CompilerModuleExporter.class);
+
+  private static final String COMPILER_PLUGIN_CLASS_PREFIX = "datadog/compiler/";
+  private static final String[] COMPILER_PACKAGES = {
+    "com.sun.tools.javac.api",
+    "com.sun.tools.javac.code",
+    "com.sun.tools.javac.comp",
+    "com.sun.tools.javac.tree",
+    "com.sun.tools.javac.util"
+  };
+
+  private final Instrumentation inst;
+  private final Set<ClassLoader> exportedClassLoaders =
+      Collections.newSetFromMap(new ConcurrentHashMap<>());
+
+  public CompilerModuleExporter(Instrumentation inst) {
+    this.inst = inst;
+  }
+
+  @Override
+  public byte[] transform(
+      ClassLoader loader,
+      String className,
+      Class<?> classBeingRedefined,
+      ProtectionDomain protectionDomain,
+      byte[] classfileBuffer) {
+    if (loader != null
+        && className != null
+        && className.startsWith(COMPILER_PLUGIN_CLASS_PREFIX)
+        && exportedClassLoaders.add(loader)) {
+      try {
+        JDK9ModuleAccess.exportModuleToUnnamedModule(
+            inst, "jdk.compiler", COMPILER_PACKAGES, loader);
+        LOGGER.debug("Exported jdk.compiler to classloader {}", loader);
+      } catch (Throwable e) {
+        LOGGER.debug("Could not export jdk.compiler packages for compiler plugin", e);
+      }
+    }
+    return null; // no bytecode modification
+  }
+}

dd-smoke-tests/gradle/src/test/groovy/datadog/smoketest/GradleDaemonSmokeTest.groovy

@@ -20,9 +20,6 @@ import spock.lang.IgnoreIf
 import spock.lang.Shared
 import spock.lang.TempDir
 
-@IgnoreIf(reason = "TODO: Fix for Java 26. Javac plugin fails to populate source tags correctly.", value = {
-  JavaVirtualMachine.isJavaVersionAtLeast(26)
-})
 class GradleDaemonSmokeTest extends AbstractGradleTest {
 
   private static final String TEST_SERVICE_NAME = "test-gradle-service"

dd-smoke-tests/maven/src/test/groovy/datadog/smoketest/MavenSmokeTest.groovy

@@ -25,9 +25,6 @@ import java.util.concurrent.TimeoutException
 
 import static org.junit.jupiter.api.Assumptions.assumeTrue
 
-@IgnoreIf(reason = "TODO: Fix for Java 26. Maven compiler fails to compile the tests for Java 26-ea.", value = {
-  JavaVirtualMachine.isJavaVersionAtLeast(26)
-})
 @IgnoreIf(reason = "IBM8 has flaky AES-GCM TLS failures when downloading Maven artifacts", value = {
   JavaVirtualMachine.isIbm8()
 })

dd-smoke-tests/maven/src/test/resources/test_successful_maven_run_junit_platform_runner/pom.xml

@@ -57,7 +57,7 @@
       <dependency>
         <groupId>org.apache.groovy</groupId>
         <artifactId>groovy-bom</artifactId>
-        <version>4.0.28</version>
+        <version>4.0.30</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>

internal-api/internal-api-9/src/main/java/datadog/trace/util/JDK9ModuleAccess.java

@@ -5,6 +5,9 @@
 
 import java.lang.instrument.Instrumentation;
 import java.lang.reflect.AnnotatedElement;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Set;
 
 /** Use standard API to work with JPMS modules on Java9+. */
@@ -33,4 +36,28 @@ public static void addModuleReads(
         emptySet(),
         emptyMap());
   }
+
+  /** Exports specific packages of a named module to a classloader's unnamed module. */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  public static void exportModuleToUnnamedModule(
+      Instrumentation inst,
+      String moduleName,
+      String[] packageNames,
+      ClassLoader targetClassLoader) {
+    java.util.Optional<java.lang.Module> optModule =
+        java.lang.ModuleLayer.boot().findModule(moduleName);
+    if (!optModule.isPresent()) {
+      return;
+    }
+    java.lang.Module module = optModule.get();
+    java.lang.Module unnamedModule = targetClassLoader.getUnnamedModule();
+
+    Set<java.lang.Module> target = Collections.singleton(unnamedModule);
+    Map<String, Set<java.lang.Module>> extraExports = new HashMap<>();
+    for (String packageName : packageNames) {
+      extraExports.put(packageName, target);
+    }
+
+    inst.redefineModule(module, emptySet(), (Map) extraExports, emptyMap(), emptySet(), emptyMap());
+  }
 }