feat: Update event IDs in BaseLlmFlow's post processing section

core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java

@@ -415,6 +415,11 @@ private Flowable<Event> runOneStep(Context spanContext, InvocationContext contex
                                 })
                             .concatMap(
                                 event -> {
+                                  // Update event ID for the new resulting events
+                                  String oldId = event.id();
+                                  String newId = Event.generateEventId();
+                                  logger.debug("Resetting event ID from {} to {}", oldId, newId);
+                                  event = event.toBuilder().id(newId).build();
                                   Flowable<Event> postProcessedEvents = Flowable.just(event);
                                   if (event.actions().transferToAgent().isPresent()) {
                                     String agentToTransfer =

core/src/test/java/com/google/adk/flows/llmflows/ToolRequestConfirmationActionTest.java

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.adk.flows.llmflows;
+
+import static com.google.adk.testing.TestUtils.createInvocationContext;
+import static com.google.adk.testing.TestUtils.createLlmResponse;
+import static com.google.adk.testing.TestUtils.createTestAgentBuilder;
+import static com.google.adk.testing.TestUtils.createTestLlm;
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.adk.agents.InvocationContext;
+import com.google.adk.agents.LlmAgent;
+import com.google.adk.events.Event;
+import com.google.adk.runner.InMemoryRunner;
+import com.google.adk.runner.Runner;
+import com.google.adk.sessions.Session;
+import com.google.adk.tools.BaseTool;
+import com.google.adk.tools.ToolContext;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.genai.types.Content;
+import com.google.genai.types.FunctionDeclaration;
+import com.google.genai.types.Part;
+import com.google.genai.types.Schema;
+import io.reactivex.rxjava3.core.Flowable;
+import io.reactivex.rxjava3.core.Single;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public final class ToolRequestConfirmationActionTest {
+
+  private static class ToolRequestConfirmationTool extends BaseTool {
+    ToolRequestConfirmationTool() {
+      super("request_confirmation_tool", "Requests confirmation.");
+    }
+
+    @Override
+    public Optional<FunctionDeclaration> declaration() {
+      return Optional.of(
+          FunctionDeclaration.builder()
+              .name(name())
+              .description(description())
+              .parameters(Schema.builder().type("OBJECT").build()) // No parameters needed
+              .build());
+    }
+
+    @Override
+    public Single<Map<String, Object>> runAsync(Map<String, Object> args, ToolContext toolContext) {
+      toolContext.requestConfirmation("Please confirm this action");
+      return Single.just(ImmutableMap.of());
+    }
+  }
+
+  @Test
+  public void toolRequestConfirmation_eventHasNonNullId() {
+    Content requestConfirmationCallContent =
+        Content.fromParts(Part.fromFunctionCall("request_confirmation_tool", ImmutableMap.of()));
+    Content response1 = Content.fromParts(Part.fromText("response1"));
+    Content response2 = Content.fromParts(Part.fromText("response2"));
+
+    var testLlm =
+        createTestLlm(
+            Flowable.just(createLlmResponse(requestConfirmationCallContent)),
+            Flowable.just(createLlmResponse(response1)),
+            Flowable.just(createLlmResponse(response2)));
+
+    LlmAgent rootAgent =
+        createTestAgentBuilder(testLlm)
+            .name("root_agent")
+            .tools(ImmutableList.of(new ToolRequestConfirmationTool()))
+            .build();
+    InvocationContext invocationContext = createInvocationContext(rootAgent);
+
+    Runner runner = getRunnerAndCreateSession(rootAgent, invocationContext.session());
+
+    ImmutableList<Event> confirmationEvents =
+        runRunner(runner, invocationContext).stream()
+            .filter(
+                e ->
+                    e.functionCalls().stream()
+                        .anyMatch(
+                            f ->
+                                Objects.equals(
+                                    f.name().orElse(""),
+                                    Functions.REQUEST_CONFIRMATION_FUNCTION_CALL_NAME)))
+            .collect(toImmutableList());
+
+    assertThat(confirmationEvents).isNotEmpty();
+    assertThat(confirmationEvents.get(0).id()).isNotNull();
+  }
+
+  private Runner getRunnerAndCreateSession(LlmAgent agent, Session session) {
+    Runner runner = new InMemoryRunner(agent, session.appName());
+
+    var unused =
+        runner
+            .sessionService()
+            .createSession(session.appName(), session.userId(), session.state(), session.id())
+            .blockingGet();
+
+    return runner;
+  }
+
+  private List<Event> runRunner(Runner runner, InvocationContext invocationContext) {
+    Session session = invocationContext.session();
+    return runner
+        .runAsync(session.userId(), session.id(), invocationContext.userContent().orElse(null))
+        .toList()
+        .blockingGet();
+  }
+}