chore: Copies latest session state to the passed-in session for runAsync with Session

Jacksunwei · copybara-github · commit 1cafa7d70828 · 2025-10-16T11:23:50.000-07:00
NOTE: `runAsync` with `Session` object was an early interface and doesn't comply with ADK interfaces across languages. Adding this behavior back is to temporarily restore previous behavior.

Here are some clarifications of the behavior:

- Any changes to the passed-in `Session` object at `runAsync` callsite won't affect agent run;
- Callsite should always use session service to get latest session if they need to access session, instead of reading into the passed-in session object.
- All runAsync with Session object will be deprecated and removed in future versions.

PiperOrigin-RevId: 820077843
diff --git a/core/src/main/java/com/google/adk/runner/Runner.java b/core/src/main/java/com/google/adk/runner/Runner.java
@@ -321,14 +321,20 @@ public Flowable<Event> runAsync(
                                                       this.sessionService
                                                           .appendEvent(updatedSession, agentEvent)
                                                           .flatMap(
-                                                              registeredEvent ->
-                                                                  contextWithUpdatedSession
-                                                                      .pluginManager()
-                                                                      .runOnEventCallback(
-                                                                          contextWithUpdatedSession,
-                                                                          registeredEvent)
-                                                                      .defaultIfEmpty(
-                                                                          registeredEvent))
+                                                              registeredEvent -> {
+                                                                // TODO: remove this hack after
+                                                                // deprecating runAsync with
+                                                                // Session.
+                                                                copySessionStates(
+                                                                    updatedSession, session);
+                                                                return contextWithUpdatedSession
+                                                                    .pluginManager()
+                                                                    .runOnEventCallback(
+                                                                        contextWithUpdatedSession,
+                                                                        registeredEvent)
+                                                                    .defaultIfEmpty(
+                                                                        registeredEvent);
+                                                              })
                                                           .toFlowable());
 
                                       // If beforeRunCallback returns content, emit it and skip
@@ -359,6 +365,13 @@ public Flowable<Event> runAsync(
     }
   }
 
+  private void copySessionStates(Session source, Session target) {
+    // TODO: remove this hack when deprecating all runAsync with Session.
+    for (var entry : source.state().entrySet()) {
+      target.state().put(entry.getKey(), entry.getValue());
+    }
+  }
+
   /**
    * Creates an {@link InvocationContext} for a live (streaming) run.
    *
