final updates

Author: mhlidd

dd-java-agent/instrumentation/armeria/armeria-grpc-0.84/src/main/java/datadog/trace/instrumentation/armeria/grpc/client/GrpcInjectAdapter.java

@@ -12,8 +12,10 @@ public final class GrpcInjectAdapter implements CarrierSetter<Metadata> {
   @Override
   public void set(final Metadata carrier, final String key, final String value) {
     Metadata.Key<String> metadataKey = Metadata.Key.of(key, Metadata.ASCII_STRING_MARSHALLER);
-    if (!carrier.containsKey(metadataKey)) {
-      carrier.put(metadataKey, value);
+    if (carrier.containsKey(metadataKey)) {
+      carrier.removeAll(
+          metadataKey); // Remove existing to ensure identical behavior with other carriers
     }
+    carrier.put(metadataKey, value);
   }
 }

dd-java-agent/instrumentation/armeria/armeria-grpc-0.84/src/test/groovy/GrpcInjectAdapterTest.groovy

@@ -3,7 +3,7 @@ import io.grpc.Metadata
 import static datadog.trace.instrumentation.grpc.client.GrpcInjectAdapter.SETTER
 
 class GrpcInjectAdapterTest extends VersionedNamingTestBase {
-  def "carrier set is called only once per unique ot-baggage-* key"() {
+  def "carrier overrides values for duplicate keys"() {
     setup:
     def carrier = new Metadata()
 
@@ -21,7 +21,7 @@ class GrpcInjectAdapterTest extends VersionedNamingTestBase {
 
     then:
     carrier.headerCount() == 2
-    carrier.get(getKey("ot-baggage-foo")) == "v1" // first value wins
+    carrier.get(getKey("ot-baggage-foo")) == "v2" // overridden value wins
     carrier.get(getKey("ot-baggage-bar")) == "v3"
   }
 

dd-java-agent/instrumentation/grpc-1.5/src/main/java/datadog/trace/instrumentation/grpc/client/GrpcInjectAdapter.java

@@ -11,8 +11,10 @@ public final class GrpcInjectAdapter implements CarrierSetter<Metadata> {
   @Override
   public void set(final Metadata carrier, final String key, final String value) {
     Metadata.Key<String> metadataKey = Metadata.Key.of(key, Metadata.ASCII_STRING_MARSHALLER);
-    if (!carrier.containsKey(metadataKey)) {
-      carrier.put(metadataKey, value);
+    if (carrier.containsKey(metadataKey)) {
+      carrier.removeAll(
+          metadataKey); // Remove existing to ensure identical behavior with other carriers
     }
+    carrier.put(metadataKey, value);
   }
 }

dd-java-agent/instrumentation/grpc-1.5/src/test/groovy/GrpcInjectAdapterTest.groovy

@@ -3,7 +3,7 @@ import io.grpc.Metadata
 import static datadog.trace.instrumentation.grpc.client.GrpcInjectAdapter.SETTER
 
 class GrpcInjectAdapterTest extends VersionedNamingTestBase {
-  def "carrier set is called only once per unique ot-baggage-* key"() {
+  def "carrier overrides values for duplicate keys"() {
     setup:
     def carrier = new Metadata()
 
@@ -21,7 +21,7 @@ class GrpcInjectAdapterTest extends VersionedNamingTestBase {
 
     then:
     carrier.headerCount() == 2
-    carrier.get(getKey("ot-baggage-foo")) == "v1" // first value wins
+    carrier.get(getKey("ot-baggage-foo")) == "v2" // overridden value wins
     carrier.get(getKey("ot-baggage-bar")) == "v3"
   }