fix: IncludeContents.None not including user message in request

PiperOrigin-RevId: 794155407

Author: Poggecci

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

@@ -56,7 +56,12 @@ public Single<RequestProcessor.RequestProcessingResult> processRequest(
     if (llmAgent.includeContents() == LlmAgent.IncludeContents.NONE) {
       return Single.just(
           RequestProcessor.RequestProcessingResult.create(
-              request.toBuilder().contents(ImmutableList.of()).build(), ImmutableList.of()));
+              request.toBuilder()
+                  .contents(
+                      getCurrentTurnContents(
+                          context.branch(), context.session().events(), context.agent().name()))
+                  .build(),
+              ImmutableList.of()));
     }
 
     ImmutableList<Content> contents =
@@ -67,6 +72,19 @@ public Single<RequestProcessor.RequestProcessingResult> processRequest(
             request.toBuilder().contents(contents).build(), ImmutableList.of()));
   }
 
+  /** Gets contents for the current turn only (no conversation history). */
+  private ImmutableList<Content> getCurrentTurnContents(
+      Optional<String> currentBranch, List<Event> events, String agentName) {
+    // Find the latest event that starts the current turn and process from there.
+    for (int i = events.size() - 1; i >= 0; i--) {
+      Event event = events.get(i);
+      if (event.author().equals("user") || isOtherAgentReply(agentName, event)) {
+        return getContents(currentBranch, events.subList(i, events.size()), agentName);
+      }
+    }
+    return ImmutableList.of();
+  }
+
   private ImmutableList<Content> getContents(
       Optional<String> currentBranch, List<Event> events, String agentName) {
     List<Event> filteredEvents = new ArrayList<>();

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

@@ -367,6 +367,84 @@ public void convertForeignEvent_eventsFromOtherAgents_returnsContextualOnlyEvent
         .inOrder();
   }
 
+  @Test
+  public void processRequest_includeContentsNone_lastEventIsUser() {
+    ImmutableList<Event> events =
+        ImmutableList.of(
+            createUserEvent("u1", "Turn 1"),
+            createAgentEvent("a1", "Reply 1"),
+            createUserEvent("u2", "Turn 2"));
+    List<Content> result =
+        runContentsProcessorWithIncludeContents(events, LlmAgent.IncludeContents.NONE);
+    assertThat(result).containsExactly(events.get(2).content().get());
+  }
+
+  @Test
+  public void processRequest_includeContentsNone_lastEventIsOtherAgent() {
+    ImmutableList<Event> events =
+        ImmutableList.of(
+            createUserEvent("u1", "Turn 1"),
+            createAgentEvent("a1", "Reply 1"),
+            createAgentEvent(OTHER_AGENT, "oa1", "Other Agent Turn"));
+    List<Content> result =
+        runContentsProcessorWithIncludeContents(events, LlmAgent.IncludeContents.NONE);
+    assertThat(result)
+        .containsExactly(
+            Content.fromParts(
+                Part.fromText("For context:"),
+                Part.fromText("[other_agent] said: Other Agent Turn")));
+  }
+
+  @Test
+  public void processRequest_includeContentsNone_noUserMessage() {
+    ImmutableList<Event> events =
+        ImmutableList.of(
+            createAgentEvent("a1", "Reply 1"),
+            createFunctionCallEvent("fc1", "tool1", "call1"),
+            createFunctionResponseEvent("fr1", "tool1", "call1"));
+    List<Content> result =
+        runContentsProcessorWithIncludeContents(events, LlmAgent.IncludeContents.NONE);
+    assertThat(result).isEmpty();
+  }
+
+  @Test
+  public void processRequest_includeContentsNone_asyncFRAcrossTurns_throwsException() {
+    Event u1 = createUserEvent("u1", "Query 1");
+    Event fc1 = createFunctionCallEvent("fc1", "tool1", "call1");
+    Event u2 = createUserEvent("u2", "Query 2");
+    Event fr1 = createFunctionResponseEvent("fr1", "tool1", "call1"); // FR for fc1
+
+    ImmutableList<Event> events = ImmutableList.of(u1, fc1, u2, fr1);
+
+    // The current turn starts from u2. fc1 is not in the sublist [u2, fr1], so rearrangement fails.
+    IllegalStateException e =
+        assertThrows(
+            IllegalStateException.class,
+            () -> runContentsProcessorWithIncludeContents(events, LlmAgent.IncludeContents.NONE));
+    assertThat(e)
+        .hasMessageThat()
+        .contains("No function call event found for function response IDs: [call1]");
+  }
+
+  @Test
+  public void processRequest_includeContentsNone_asyncFRWithinTurn() {
+    Event u1 = createUserEvent("u1", "Query 1");
+    Event fc1 = createFunctionCallEvent("fc1", "tool1", "call1");
+    Event a1 = createAgentEvent("a1", "Agent thinking");
+    Event fr1 = createFunctionResponseEvent("fr1", "tool1", "call1");
+
+    ImmutableList<Event> events = ImmutableList.of(u1, fc1, a1, fr1);
+    // Current turn starts with u1. The list passed to getContents is [u1, fc1, a1, fr1].
+    List<Content> result =
+        runContentsProcessorWithIncludeContents(events, LlmAgent.IncludeContents.NONE);
+    assertThat(result)
+        .containsExactly(
+            events.get(0).content().get(), // u1
+            events.get(1).content().get(), // fc1
+            events.get(3).content().get()) // fr1 (merged)
+        .inOrder();
+  }
+
   private static Event createUserEvent(String id, String text) {
     return Event.builder()
         .id(id)
@@ -503,7 +581,12 @@ private static Event createFunctionResponseEvent(
   }
 
   private List<Content> runContentsProcessor(List<Event> events) {
-    LlmAgent agent = LlmAgent.builder().name(AGENT).build();
+    return runContentsProcessorWithIncludeContents(events, LlmAgent.IncludeContents.DEFAULT);
+  }
+
+  private List<Content> runContentsProcessorWithIncludeContents(
+      List<Event> events, LlmAgent.IncludeContents includeContents) {
+    LlmAgent agent = LlmAgent.builder().name(AGENT).includeContents(includeContents).build();
     Session session =
         Session.builder("test-session")
             .appName("test-app")