fixes bug setting service names to empty (#1428)

Signed-off-by: Adrian Cole <[email protected]>

Author: codefromthecrypt

brave/src/main/java/brave/handler/MutableSpan.java

@@ -365,8 +365,9 @@ public void kind(@Nullable Kind kind) {
   public void localServiceName(@Nullable String localServiceName) {
     if (localServiceName == null || localServiceName.isEmpty()) {
       this.localServiceName = null;
+    } else {
+      this.localServiceName = localServiceName;
     }
-    this.localServiceName = localServiceName;
   }
 
   /**
@@ -438,8 +439,9 @@ public void localPort(int localPort) {
   public void remoteServiceName(@Nullable String remoteServiceName) {
     if (remoteServiceName == null || remoteServiceName.isEmpty()) {
       this.remoteServiceName = null;
+    } else {
+      this.remoteServiceName = remoteServiceName;
     }
-    this.remoteServiceName = remoteServiceName;
   }
 
   /**

brave/src/test/java/brave/handler/MutableSpanTest.java

@@ -285,13 +285,27 @@ class Tag {
     );
   }
 
+  @Test void localServiceNameCoercesEmptyToNull() {
+    MutableSpan span = new MutableSpan();
+    span.localServiceName("FavStar");
+    span.localServiceName("");
+    assertThat(span.localServiceName()).isNull();
+  }
+
   @Test void localServiceNamePreservesCase() {
     String expectedLocalServiceName = "FavStar";
     MutableSpan span = new MutableSpan();
     span.localServiceName(expectedLocalServiceName);
     assertThat(span.localServiceName()).isEqualTo(expectedLocalServiceName);
   }
 
+  @Test void remoteServiceNameCoercesEmptyToNull() {
+    MutableSpan span = new MutableSpan();
+    span.remoteServiceName("FavStar");
+    span.remoteServiceName("");
+    assertThat(span.remoteServiceName()).isNull();
+  }
+
   @Test void remoteServiceNamePreservesCase() {
     String expectedRemoteServiceName = "FavStar";
     MutableSpan span = new MutableSpan();