fix(okhttp): capture scope at AsyncCall.<init> to keep traces intact under virtual-thread Dispatcher

dd-java-agent/instrumentation/okhttp/okhttp-3.0/build.gradle

@@ -8,9 +8,30 @@ muzzle {
 }
 
 apply from: "$rootDir/gradle/java.gradle"
+// Use slf4j-simple for tests; logback's synchronized appenders can pin virtual-thread carriers
+// when many vthreads log concurrently, which deadlocks this module's vthread21Test suite.
+apply from: "$rootDir/gradle/slf4j-simple.gradle"
 
 addTestSuiteForDir('latestDepTest', 'test')
 
+// Separate suite for tests that need the JDK 21+ virtual-thread API. Kept apart from the
+// default test suite so that the existing OkHttp 3.0 tests keep their Java 1.8 baseline.
+addTestSuite('vthread21Test')
+
+tasks.named("compileVthread21TestJava", JavaCompile) {
+  configureCompiler(it, 21)
+}
+
+tasks.named("vthread21Test", Test) {
+  testJvmConstraints {
+    minJavaVersion = JavaVersion.VERSION_21
+  }
+}
+
+tasks.named("check") {
+  dependsOn "vthread21Test"
+}
+
 dependencies {
   compileOnly(group: 'com.squareup.okhttp3', name: 'okhttp', version: '3.0.0')
 
@@ -38,4 +59,14 @@ dependencies {
 
   testRuntimeOnly(project(':dd-java-agent:instrumentation:datadog:asm:iast-instrumenter'))
   testRuntimeOnly(project(':dd-java-agent:instrumentation:java:java-net:java-net-1.8'))
+
+  // vthread21Test inherits testImplementation via addTestSuite's extendsFrom wiring.
+  vthread21TestImplementation(group: 'com.squareup.okhttp3', name: 'okhttp', version: '3.11.0')
+  vthread21TestImplementation(group: 'com.squareup.okio', name: 'okio', version: '1.14.0')
+
+  // Pull in the JDK-21+ concurrent / lang instrumentations so the test installs the same
+  // TaskRunnerInstrumentation + VirtualThreadInstrumentation chain that profiling-backend
+  // exercises in production.
+  vthread21TestRuntimeOnly project(':dd-java-agent:instrumentation:java:java-concurrent:java-concurrent-21.0')
+  vthread21TestRuntimeOnly project(':dd-java-agent:instrumentation:java:java-lang:java-lang-21.0')
 }

dd-java-agent/instrumentation/okhttp/okhttp-3.0/src/main/java/datadog/trace/instrumentation/okhttp3/AsyncCallInstrumentation.java

@@ -0,0 +1,71 @@
+package datadog.trace.instrumentation.okhttp3;
+
+import static datadog.trace.bootstrap.instrumentation.java.concurrent.AdviceUtils.capture;
+import static java.util.Collections.singletonMap;
+import static net.bytebuddy.matcher.ElementMatchers.isConstructor;
+
+import com.google.auto.service.AutoService;
+import datadog.trace.agent.tooling.Instrumenter;
+import datadog.trace.agent.tooling.InstrumenterModule;
+import datadog.trace.bootstrap.InstrumentationContext;
+import datadog.trace.bootstrap.instrumentation.java.concurrent.State;
+import java.util.Map;
+import net.bytebuddy.asm.Advice;
+
+/**
+ * Captures the active scope at {@code AsyncCall.<init>} (i.e. the moment {@code
+ * Call.enqueue(callback)} was invoked on the user's thread) and stores it in the {@code
+ * ContextStore<Runnable, State>} shared with the rest of the concurrent instrumentation. {@code
+ * RunnableInstrumentation} then re-activates that scope on {@code AsyncCall.run()} entry, which
+ * overrides whatever scope {@code TaskRunner.run()} (or {@code beforeExecute}) put in place from
+ * the dispatcher's worker thread.
+ *
+ * <p>Without this, {@code TaskRunnerInstrumentation} captures whatever scope happens to be active
+ * on the worker thread when {@code Dispatcher.promoteAndExecute()} dequeues and submits the call —
+ * and when promotion runs from inside {@code Dispatcher.finished()} (i.e. recursively from a
+ * <em>different</em> AsyncCall's run()), that scope belongs to the finishing call, not to the
+ * caller who actually enqueued this AsyncCall. Result: under concurrent OkHttp load, {@code
+ * okhttp.request} spans cross-contaminate between traces.
+ *
+ * <p>{@code AsyncCall} is an inner class of {@code RealCall} and transitively implements {@link
+ * Runnable}.
+ */
+@AutoService(InstrumenterModule.class)
+public final class AsyncCallInstrumentation extends InstrumenterModule.Tracing
+    implements Instrumenter.ForKnownTypes, Instrumenter.HasMethodAdvice {
+
+  public AsyncCallInstrumentation() {
+    // Re-use the existing "okhttp" / "okhttp-3" instrumentation names so we don't introduce a
+    // separately-toggleable feature flag (DD_TRACE_OKHTTP_ASYNC_CALL_ENABLED). The capture here
+    // is conceptually part of the OkHttp instrumentation — if you disable OkHttp tracing, you
+    // also disable this capture, which is the right behavior.
+    super("okhttp", "okhttp-3");
+  }
+
+  @Override
+  public String[] knownMatchingTypes() {
+    return new String[] {
+      "okhttp3.RealCall$AsyncCall",
+    };
+  }
+
+  @Override
+  public Map<String, String> contextStore() {
+    // Same Runnable -> State store that RunnableInstrumentation reads from.
+    return singletonMap("java.lang.Runnable", State.class.getName());
+  }
+
+  @Override
+  public void methodAdvice(MethodTransformer transformer) {
+    transformer.applyAdvice(isConstructor(), getClass().getName() + "$Construct");
+  }
+
+  public static final class Construct {
+    @Advice.OnMethodExit(suppress = Throwable.class)
+    public static void captureScope(@Advice.This Runnable asyncCall) {
+      // AdviceUtils.capture is a no-op when async propagation is disabled or there's no active
+      // span — same behavior as the rest of the concurrent instrumentation.
+      capture(InstrumentationContext.get(Runnable.class, State.class), asyncCall);
+    }
+  }
+}