wip -- tofix

Author: realark

braintrust-java-agent/bootstrap/src/main/java/dev/braintrust/system/AgentBootstrap.java

@@ -5,6 +5,7 @@
 import java.io.File;
 import java.lang.instrument.Instrumentation;
 import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.jar.JarFile;
 
 /**
@@ -44,15 +45,12 @@ private static synchronized void install(String agentArgs, Instrumentation inst)
 
         if (jvmRunningWithOtelAgent()) {
             log(
-                    "ERROR: Braintrust agent is not yet compatible with the OTel javaagent -"
-                            + " skipping install.");
+                    "ERROR: Braintrust agent is not yet compatible with the OTel -javaagent."
+                            + " aborting install.");
             return;
         }
-
-        if (jvmRunningWithDatadogOtel()) {
-            log(
-                    "ERROR: Braintrust agent is not yet compatible with datadog javaagent otel -"
-                            + " skipping install.");
+        if (jvmRunningWithDatadogOtel() && (!isRunningAfterDatadogAgent())) {
+            log("ERROR: Braintrust agent must run _after_ datadog -javaagent. aborting install.");
             return;
         }
 
@@ -67,16 +65,28 @@ private static synchronized void install(String agentArgs, Instrumentation inst)
             // are set before anything can trigger GlobalOpenTelemetry.get().
             enableOtelSDKAutoconfiguration();
 
-            inst.appendToBootstrapClassLoaderSearch(new JarFile(agentJarFile, false));
-            log("Added agent JAR to bootstrap classpath.");
+            if (!jvmRunningWithDatadogOtel()) {
+                inst.appendToBootstrapClassLoaderSearch(new JarFile(agentJarFile, false));
+                log("Added agent JAR to bootstrap classpath.");
+            } else {
+                log("datadog detected, skipping bootstrap classpath setup");
+            }
 
             // Create the isolated braintrust classloader.
             // Parent is the platform classloader so agent internals can see:
             //   - Bootstrap classes (OTel API/SDK added via appendToBootstrapClassLoaderSearch)
             //   - JDK platform modules (java.net.http, java.sql, etc.)
             // but NOT application classes (those are on the system/app classloader).
+            ClassLoader otherCL =
+                    new URLClassLoader(
+                            new URL[] {agentJarFile.toURI().toURL()},
+                            ClassLoader.getPlatformClassLoader());
             BraintrustClassLoader btClassLoader =
-                    new BraintrustClassLoader(agentJarURL, ClassLoader.getPlatformClassLoader());
+                    new BraintrustClassLoader(
+                            agentJarURL,
+                            jvmRunningWithDatadogOtel()
+                                    ? otherCL
+                                    : ClassLoader.getPlatformClassLoader());
             BraintrustBridge.setAgentClassLoaderIfAbsent(btClassLoader);
 
             // Load and invoke the real agent installer through the isolated classloader.
@@ -109,16 +119,8 @@ private static boolean jvmRunningWithOtelAgent() {
         }
     }
 
-    /**
-     * Checks whether the Datadog agent is present and configured for OTel integration. Must be
-     * callable from the system classloader (no DD compile deps).
-     */
+    /** Checks whether the Datadog agent is present and configured for OTel integration */
     private static boolean jvmRunningWithDatadogOtel() {
-        try {
-            Class.forName("datadog.trace.bootstrap.Agent", false, null);
-        } catch (ClassNotFoundException e) {
-            return false;
-        }
         String sysProp = System.getProperty("dd.trace.otel.enabled");
         if (sysProp != null) {
             return Boolean.parseBoolean(sysProp);
@@ -131,7 +133,7 @@ private static boolean jvmRunningWithDatadogOtel() {
      * Returns true if the Datadog agent's premain has already executed, meaning it was listed
      * before the Braintrust agent in the {@code -javaagent} flags.
      */
-    static boolean isRunningAfterDatadogAgent() {
+    private static boolean isRunningAfterDatadogAgent() {
         // DD's premain appends its jars to the bootstrap classpath, making
         // {@code datadog.trace.bootstrap.Agent} loadable from the bootstrap (null)
         // classloader. If that class is not found on bootstrap, DD either isn't

braintrust-java-agent/internal/src/main/java/dev/braintrust/agent/BraintrustAgent.java

@@ -3,7 +3,6 @@
 import com.google.auto.service.AutoService;
 import dev.braintrust.Braintrust;
 import dev.braintrust.bootstrap.BraintrustBridge;
-import dev.braintrust.bootstrap.BraintrustClassLoader;
 import dev.braintrust.instrumentation.Instrumenter;
 import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer;
 import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizerProvider;
@@ -19,10 +18,12 @@ public class BraintrustAgent implements AutoConfigurationCustomizerProvider {
 
     /** Called reflectively from AgentBootstrap premain. */
     public static void install(String agentArgs, Instrumentation inst) {
+        /* TODO
         if (!(BraintrustAgent.class.getClassLoader() instanceof BraintrustClassLoader)) {
             throw new IllegalStateException(
-                    "Braintrust agent can only run on a braintrust classloader");
+                    "Braintrust agent can only run on a braintrust classloader: " + BraintrustAgent.class.getClassLoader());
         }
+         */
         log.info(
                 "invoked on classloader: {}",
                 BraintrustAgent.class.getClassLoader().getClass().getName());