Avoid forking rootScopes for Reactor if current thread has NoOpScopes

CHANGELOG.md

@@ -29,6 +29,8 @@
 - Fix profilerId propagation ([#4833](https://github.com/getsentry/sentry-java/pull/4833))
 - Fix profiling init for Spring and Spring Boot w Agent auto-init ([#4815](https://github.com/getsentry/sentry-java/pull/4815))
 - Copy active span on scope clone ([#4878](https://github.com/getsentry/sentry-java/pull/4878))
+- Avoid forking `rootScopes` for Reactor if current thread has NoOpScopes ([#4793](https://github.com/getsentry/sentry-java/pull/4793))
+  - This reduces the SDKs overhead by avoiding unnecessary scope forks
 
 ### Improvements
 

sentry-reactor/src/main/java/io/sentry/reactor/SentryReactorThreadLocalAccessor.java

@@ -16,7 +16,7 @@ public Object key() {
 
   @Override
   public IScopes getValue() {
-    return Sentry.getCurrentScopes();
+    return Sentry.getCurrentScopes(false);
   }
 
   @Override

sentry/api/sentry.api

@@ -2631,6 +2631,7 @@ public final class io/sentry/Sentry {
 	public static fun getBaggage ()Lio/sentry/BaggageHeader;
 	public static fun getCurrentHub ()Lio/sentry/IHub;
 	public static fun getCurrentScopes ()Lio/sentry/IScopes;
+	public static fun getCurrentScopes (Z)Lio/sentry/IScopes;
 	public static fun getGlobalScope ()Lio/sentry/IScope;
 	public static fun getLastEventId ()Lio/sentry/protocol/SentryId;
 	public static fun getSpan ()Lio/sentry/ISpan;

sentry/src/main/java/io/sentry/Sentry.java

@@ -97,16 +97,33 @@ private Sentry() {}
     return new HubScopesWrapper(getCurrentScopes());
   }
 
-  @ApiStatus.Internal // exposed for the coroutines integration in SentryContext
+  @ApiStatus.Internal
   @SuppressWarnings("deprecation")
   public static @NotNull IScopes getCurrentScopes() {
+    return getCurrentScopes(true);
+  }
+
+  /**
+   * Returns the current contexts scopes.
+   *
+   * @param ensureForked if true, forks root scopes in case there are no scopes for this context if
+   *     false, returns NoOpScopes if there are no scopes for this context
+   * @return current scopes, a root scopes fork or NoopScopes
+   */
+  @ApiStatus.Internal
+  @SuppressWarnings("deprecation")
+  public static @NotNull IScopes getCurrentScopes(final boolean ensureForked) {
     if (globalHubMode) {
       return rootScopes;
     }
     @Nullable IScopes scopes = getScopesStorage().get();
     if (scopes == null || scopes.isNoOp()) {
-      scopes = rootScopes.forkedScopes("getCurrentScopes");
-      getScopesStorage().set(scopes);
+      if (!ensureForked) {
+        return NoOpScopes.getInstance();
+      } else {
+        scopes = rootScopes.forkedScopes("getCurrentScopes");
+        getScopesStorage().set(scopes);
+      }
     }
     return scopes;
   }