Propagate baggage to the parent context in SpanBuilderShim

opentracing-shim/src/main/java/io/opentelemetry/opentracingshim/SpanBuilderShim.java

@@ -197,8 +197,9 @@ public Span start() {
       builder.setNoParent();
       baggage = Baggage.empty();
     } else if (mainParent != null) {
-      builder.setParent(Context.root().with(io.opentelemetry.api.trace.Span.wrap(mainParent)));
       baggage = getAllBaggage(allParents);
+      builder.setParent(
+          Context.root().with(io.opentelemetry.api.trace.Span.wrap(mainParent)).with(baggage));
     } else {
       // No explicit parent Span, but extracted baggage may be available.
       baggage = Baggage.current();

opentracing-shim/src/test/java/io/opentelemetry/opentracingshim/SpanBuilderShimTest.java

@@ -19,8 +19,10 @@
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.api.trace.Tracer;
 import io.opentelemetry.context.Context;
+import io.opentelemetry.sdk.trace.ReadWriteSpan;
 import io.opentelemetry.sdk.trace.ReadableSpan;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import io.opentelemetry.sdk.trace.SpanProcessor;
 import io.opentelemetry.sdk.trace.data.LinkData;
 import io.opentelemetry.sdk.trace.data.SpanData;
 import io.opentelemetry.sdk.trace.data.StatusData;
@@ -31,6 +33,7 @@
 import io.opentracing.tag.Tags;
 import java.math.BigInteger;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -231,6 +234,50 @@ void baggage_parent() {
     }
   }
 
+  @Test
+  void baggage_explicitParent_inParentContext() {
+    AtomicReference<Baggage> parentContextBaggage = new AtomicReference<>();
+    SdkTracerProvider tracerSdkFactory =
+        SdkTracerProvider.builder()
+            .addSpanProcessor(
+                new SpanProcessor() {
+                  @Override
+                  public void onStart(Context parentContext, ReadWriteSpan span) {
+                    parentContextBaggage.set(Baggage.fromContext(parentContext));
+                  }
+
+                  @Override
+                  public boolean isStartRequired() {
+                    return true;
+                  }
+
+                  @Override
+                  public void onEnd(ReadableSpan span) {}
+
+                  @Override
+                  public boolean isEndRequired() {
+                    return false;
+                  }
+                })
+            .build();
+    Tracer tracer = tracerSdkFactory.get("SpanShimTest");
+
+    SpanShim parentSpan = (SpanShim) new SpanBuilderShim(tracer, SPAN_NAME).start();
+    try {
+      parentSpan.setBaggageItem("key1", "value1");
+
+      SpanShim childSpan =
+          (SpanShim) new SpanBuilderShim(tracer, SPAN_NAME).asChildOf(parentSpan).start();
+      try {
+        assertThat(parentContextBaggage.get().getEntryValue("key1")).isEqualTo("value1");
+      } finally {
+        childSpan.finish();
+      }
+    } finally {
+      parentSpan.finish();
+    }
+  }
+
   @Test
   void baggage_parentContext() {
     SpanShim parentSpan = (SpanShim) new SpanBuilderShim(tracer, SPAN_NAME).start();