GlobalOpenTelemetry.get() should never returns obfuscated Noop OpenTelemetry

Fix inconsistent behavior that first call will return Noop but later calls return obfuscated Noop.

Signed-off-by: Yanming Zhou <[email protected]>

Author: quaff

api/all/src/main/java/io/opentelemetry/api/GlobalOpenTelemetry.java

@@ -72,7 +72,7 @@ private GlobalOpenTelemetry() {}
    *     interface FQCN but the specified provider cannot be found.
    */
   public static OpenTelemetry get() {
-    OpenTelemetry openTelemetry = globalOpenTelemetry;
+    ObfuscatedOpenTelemetry openTelemetry = globalOpenTelemetry;
     if (openTelemetry == null) {
       synchronized (mutex) {
         openTelemetry = globalOpenTelemetry;
@@ -88,7 +88,7 @@ public static OpenTelemetry get() {
         }
       }
     }
-    return openTelemetry;
+    return openTelemetry.delegate == OpenTelemetry.noop() ? OpenTelemetry.noop() : openTelemetry;
   }
 
   /**

api/testing-internal/src/main/java/io/opentelemetry/api/testing/internal/AbstractOpenTelemetryTest.java

@@ -115,4 +115,11 @@ void toString_noop_Valid() {
                 + "propagators=DefaultContextPropagators{textMapPropagator=NoopTextMapPropagator}"
                 + "}");
   }
+
+  @Test
+  void neverReturnsObfuscatedNoop() {
+    assertThat(GlobalOpenTelemetry.get()).isSameAs(OpenTelemetry.noop());
+    // ensure sequential calls of GlobalOpenTelemetry.get() return same object
+    assertThat(GlobalOpenTelemetry.get()).isSameAs(OpenTelemetry.noop());
+  }
 }