fix: keep current status messages out of task history (a2aproject#1122)

* fix: preserve status message history ordering
* test: cover compat status message history

Signed-off-by: 1fanwang <1fannnw@gmail.com>

Author: 1fanwang

client/base/src/main/java/org/a2aproject/sdk/client/ClientTaskManager.java

@@ -67,12 +67,12 @@ synchronized Task saveTaskEvent(TaskStatusUpdateEvent taskStatusUpdateEvent) thr
         }
 
         Task.Builder taskBuilder = Task.builder(task);
-        if (taskStatusUpdateEvent.status().message() != null) {
+        if (task.status().message() != null) {
             if (task.history() == null) {
-                taskBuilder.history(taskStatusUpdateEvent.status().message());
+                taskBuilder.history(task.status().message());
             } else {
                 List<Message> history = new ArrayList<>(task.history());
-                history.add(taskStatusUpdateEvent.status().message());
+                history.add(task.status().message());
                 taskBuilder.history(history);
             }
         }

client/base/src/test/java/org/a2aproject/sdk/client/ClientTaskManagerTest.java

@@ -89,8 +89,8 @@ public void testSaveTaskEventWithStatusUpdate() throws Exception {
 
         assertEquals(TaskState.TASK_STATE_COMPLETED, updatedTask.status().state());
         assertNotNull(updatedTask.history());
-        assertEquals(1, updatedTask.history().size());
-        assertEquals(sampleMessage, updatedTask.history().get(0));
+        assertEquals(0, updatedTask.history().size());
+        assertEquals(sampleMessage, updatedTask.status().message());
     }
 
     @Test
@@ -251,7 +251,8 @@ public void testSaveTaskEventMultipleStatusUpdates() throws Exception {
 
         Task updatedTask1 = taskManager.saveTaskEvent(statusUpdate1);
         assertEquals(TaskState.TASK_STATE_WORKING, updatedTask1.status().state());
-        assertEquals(1, updatedTask1.history().size());
+        assertEquals(0, updatedTask1.history().size());
+        assertEquals(sampleMessage, updatedTask1.status().message());
 
         // Second status update
         Message secondMessage = Message.builder()
@@ -268,7 +269,9 @@ public void testSaveTaskEventMultipleStatusUpdates() throws Exception {
 
         Task updatedTask2 = taskManager.saveTaskEvent(statusUpdate2);
         assertEquals(TaskState.TASK_STATE_COMPLETED, updatedTask2.status().state());
-        assertEquals(2, updatedTask2.history().size());
+        assertEquals(1, updatedTask2.history().size());
+        assertEquals(sampleMessage, updatedTask2.history().get(0));
+        assertEquals(secondMessage, updatedTask2.status().message());
     }
 
     @Test

compat-0.3/client/base/src/main/java/org/a2aproject/sdk/compat03/client/ClientTaskManager_v0_3.java

@@ -67,9 +67,9 @@ Task_v0_3 saveTaskEvent(TaskStatusUpdateEvent_v0_3 taskStatusUpdateEvent) throws
         }
 
         Task_v0_3.Builder taskBuilder = new Task_v0_3.Builder(task);
-        if (taskStatusUpdateEvent.status().message() != null) {
+        if (task.status().message() != null) {
             List<Message_v0_3> history = new ArrayList<>(task.history());
-            history.add(taskStatusUpdateEvent.status().message());
+            history.add(task.status().message());
             taskBuilder.history(history);
         }
         if (taskStatusUpdateEvent.metadata() != null) {

compat-0.3/client/base/src/test/java/org/a2aproject/sdk/compat03/client/ClientTaskManager_v0_3_Test.java

@@ -0,0 +1,51 @@
+package org.a2aproject.sdk.compat03.client;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+
+import org.a2aproject.sdk.compat03.spec.Message_v0_3;
+import org.a2aproject.sdk.compat03.spec.TaskState_v0_3;
+import org.a2aproject.sdk.compat03.spec.TaskStatusUpdateEvent_v0_3;
+import org.a2aproject.sdk.compat03.spec.TaskStatus_v0_3;
+import org.a2aproject.sdk.compat03.spec.Task_v0_3;
+import org.a2aproject.sdk.compat03.spec.TextPart_v0_3;
+import org.junit.jupiter.api.Test;
+
+public class ClientTaskManager_v0_3_Test {
+
+    @Test
+    public void testStatusMessagesMoveToHistoryWhenSuperseded() throws Exception {
+        ClientTaskManager_v0_3 taskManager = new ClientTaskManager_v0_3();
+        Message_v0_3 workingMessage = new Message_v0_3.Builder()
+                .messageId("working-message")
+                .role(Message_v0_3.Role.AGENT)
+                .parts(new TextPart_v0_3("working"))
+                .build();
+        Message_v0_3 completedMessage = new Message_v0_3.Builder()
+                .messageId("completed-message")
+                .role(Message_v0_3.Role.AGENT)
+                .parts(new TextPart_v0_3("completed"))
+                .build();
+
+        Task_v0_3 workingTask = taskManager.saveTaskEvent(new TaskStatusUpdateEvent_v0_3.Builder()
+                .taskId("task-123")
+                .contextId("context-123")
+                .status(new TaskStatus_v0_3(TaskState_v0_3.WORKING, workingMessage, null))
+                .build());
+
+        assertTrue(workingTask.history().isEmpty());
+        assertEquals(workingMessage, workingTask.status().message());
+
+        Task_v0_3 completedTask = taskManager.saveTaskEvent(new TaskStatusUpdateEvent_v0_3.Builder()
+                .taskId("task-123")
+                .contextId("context-123")
+                .status(new TaskStatus_v0_3(TaskState_v0_3.COMPLETED, completedMessage, null))
+                .isFinal(true)
+                .build());
+
+        assertEquals(List.of(workingMessage), completedTask.history());
+        assertEquals(completedMessage, completedTask.status().message());
+    }
+}