feat!: Remove kind discriminator as per the 1.0 specification (#551)

Fixes #544

Author: kabir

client/transport/jsonrpc/src/test/java/io/a2a/client/transport/jsonrpc/JSONRPCTransportStreamingTest.java

@@ -168,7 +168,7 @@ public void testA2AClientResubscribeToTask() throws Exception {
         assertEquals("artifact-1", artifact.artifactId());
         assertEquals("joke", artifact.name());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) part).text());
     }
 } 

client/transport/jsonrpc/src/test/java/io/a2a/client/transport/jsonrpc/JSONRPCTransportTest.java

@@ -131,7 +131,7 @@ public void testA2AClientSendMessage() throws Exception {
         assertEquals("joke", artifact.name());
         assertEquals(1, artifact.parts().size());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) part).text());
         assertTrue(task.metadata().isEmpty());
     }
@@ -172,7 +172,7 @@ public void testA2AClientSendMessageWithMessageResponse() throws Exception {
         Message agentMessage = (Message) result;
         assertEquals(Message.Role.AGENT, agentMessage.role());
         Part<?> part = agentMessage.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) part).text());
         assertEquals("msg-456", agentMessage.messageId());
     }
@@ -243,7 +243,7 @@ public void testA2AClientGetTask() throws Exception {
         assertEquals(1, artifact.parts().size());
         assertEquals("artifact-1", artifact.artifactId());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) part).text());
         assertTrue(task.metadata().isEmpty());
         List<Message> history = task.history();
@@ -255,15 +255,15 @@ public void testA2AClientGetTask() throws Exception {
         assertNotNull(parts);
         assertEquals(3, parts.size());
         part = parts.get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("tell me a joke", ((TextPart)part).text());
         part = parts.get(1);
-        assertEquals(Part.Kind.FILE, part.getKind());
+        assertTrue(part instanceof FilePart);
         FileContent filePart = ((FilePart) part).file();
         assertEquals("file:///path/to/file.txt", ((FileWithUri) filePart).uri());
         assertEquals("text/plain", filePart.mimeType());
         part = parts.get(2);
-        assertEquals(Part.Kind.FILE, part.getKind());
+        assertTrue(part instanceof FilePart);
         filePart = ((FilePart) part).file();
         assertEquals("aGVsbG8=", ((FileWithBytes) filePart).bytes());
         assertEquals("hello.txt", filePart.name());
@@ -558,7 +558,7 @@ public void testA2AClientSendMessageWithFilePart() throws Exception {
         assertEquals("image-analysis", artifact.name());
         assertEquals(1, artifact.parts().size());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("This is an image of a cat sitting on a windowsill.", ((TextPart) part).text());
         assertFalse(task.metadata().isEmpty());
         assertEquals(1, task.metadata().size());
@@ -618,7 +618,7 @@ public void testA2AClientSendMessageWithDataPart() throws Exception {
         assertEquals("data-analysis", artifact.name());
         assertEquals(1, artifact.parts().size());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("Processed weather data: Temperature is 25.5°C, humidity is 60.2% in San Francisco.", ((TextPart) part).text());
         assertTrue(task.metadata().isEmpty());
     }
@@ -676,7 +676,7 @@ public void testA2AClientSendMessageWithMixedParts() throws Exception {
         assertEquals("mixed-analysis", artifact.name());
         assertEquals(1, artifact.parts().size());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof TextPart);
         assertEquals("Analyzed chart image and data: Bar chart showing quarterly data with values [10, 20, 30, 40].", ((TextPart) part).text());
         assertTrue(task.metadata().isEmpty());
     }

client/transport/jsonrpc/src/test/java/io/a2a/client/transport/jsonrpc/sse/SSEEventListenerTest.java

@@ -136,7 +136,7 @@ public void testOnEventWithTaskArtifactUpdateEventEvent() throws Exception {
         Artifact artifact = taskArtifactUpdateEvent.artifact();
         assertEquals("artifact-1", artifact.artifactId());
         assertEquals(1, artifact.parts().size());
-        assertEquals(Part.Kind.TEXT, artifact.parts().get(0).getKind());
+        assertTrue(artifact.parts().get(0) instanceof TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) artifact.parts().get(0)).text());
     }
 

client/transport/rest/src/test/java/io/a2a/client/transport/rest/RestTransportTest.java

@@ -48,7 +48,6 @@
 import io.a2a.spec.MessageSendConfiguration;
 import io.a2a.spec.MessageSendParams;
 import io.a2a.spec.Part;
-import io.a2a.spec.Part.Kind;
 import io.a2a.spec.PushNotificationConfig;
 import io.a2a.spec.StreamingEventKind;
 import io.a2a.spec.Task;
@@ -148,7 +147,7 @@ public void testSendMessage() throws Exception {
         assertEquals("message-1234", history.messageId());
         assertEquals("9b511af4-b27c-47fa-aecf-2a93c08a44f8", history.taskId());
         assertEquals(1, history.parts().size());
-        assertEquals(Kind.TEXT, history.parts().get(0).getKind());
+        assertTrue(history.parts().get(0) instanceof io.a2a.spec.TextPart);
         assertEquals("tell me a joke", ((TextPart) history.parts().get(0)).text());
         assertNull(task.metadata());
         assertNull(history.referenceTaskIds());
@@ -210,22 +209,22 @@ public void testGetTask() throws Exception {
         assertEquals("artifact-1", artifact.artifactId());
         assertNull(artifact.name());
         assertEquals(false, artifact.parts().isEmpty());
-        assertEquals(Kind.TEXT, artifact.parts().get(0).getKind());
+        assertTrue(artifact.parts().get(0) instanceof io.a2a.spec.TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) artifact.parts().get(0)).text());
         assertEquals(1, task.history().size());
         Message history = task.history().get(0);
         assertEquals("message", history.kind());
         assertEquals(Message.Role.USER, history.role());
         assertEquals("message-123", history.messageId());
         assertEquals(3, history.parts().size());
-        assertEquals(Kind.TEXT, history.parts().get(0).getKind());
+        assertTrue(history.parts().get(0) instanceof io.a2a.spec.TextPart);
         assertEquals("tell me a joke", ((TextPart) history.parts().get(0)).text());
-        assertEquals(Kind.FILE, history.parts().get(1).getKind());
+        assertTrue(history.parts().get(1) instanceof FilePart);
         FilePart part = (FilePart) history.parts().get(1);
         assertEquals("text/plain", part.file().mimeType());
         assertEquals("file:///path/to/file.txt", ((FileWithUri) part.file()).uri());
         part = (FilePart) history.parts().get(2);
-        assertEquals(Kind.FILE, part.getKind());
+        assertTrue(part instanceof FilePart);
         assertEquals("text/plain", part.file().mimeType());
         assertEquals("aGVsbG8=", ((FileWithBytes) part.file()).bytes());
         assertNull(history.metadata());
@@ -448,7 +447,7 @@ public void testResubscribe() throws Exception {
         assertEquals("artifact-1", artifact.artifactId());
         assertEquals("joke", artifact.name());
         Part<?> part = artifact.parts().get(0);
-        assertEquals(Part.Kind.TEXT, part.getKind());
+        assertTrue(part instanceof io.a2a.spec.TextPart);
         assertEquals("Why did the chicken cross the road? To get to the other side!", ((TextPart) part).text());
     }
 }

extras/push-notification-config-store-database-jpa/src/test/java/io/a2a/extras/pushnotificationconfigstore/database/jpa/JpaDatabasePushNotificationConfigStoreTestAgentExecutor.java

@@ -67,7 +67,7 @@ private String getLastTextPart(Message message) throws JSONRPCError {
             return "";
         }
         Part<?> part = message.parts().get(message.parts().size() - 1);
-        if (part.getKind() == Part.Kind.TEXT) {
+        if (part instanceof TextPart) {
             return ((TextPart) part).text();
         }
         throw new InvalidRequestError("Last part is not text");

extras/queue-manager-replicated/core/src/test/java/io/a2a/extras/queuemanager/replicated/core/EventSerializationTest.java

@@ -53,7 +53,7 @@ public void testTaskSerialization() throws JsonProcessingException {
 
         // Test serialization as Event
         String json = JsonUtil.toJson(originalTask);
-        assertTrue(json.contains("\"kind\":\"task\""), "JSON should contain task kind");
+        assertTrue(json.contains("\"task\""), "JSON should contain task wrapper");
         assertTrue(json.contains("\"id\":\"test-task-123\""), "JSON should contain task ID");
 
         // Test deserialization back to StreamingEventKind
@@ -84,7 +84,7 @@ public void testMessageSerialization() throws JsonProcessingException {
 
         // Test serialization as Event
         String json = JsonUtil.toJson(originalMessage);
-        assertTrue(json.contains("\"kind\":\"message\""), "JSON should contain message kind");
+        assertTrue(json.contains("\"message\""), "JSON should contain message wrapper");
         assertTrue(json.contains("\"taskId\":\"test-task-789\""), "JSON should contain task ID");
 
         // Test deserialization back to StreamingEventKind
@@ -115,7 +115,7 @@ public void testTaskStatusUpdateEventSerialization() throws JsonProcessingExcept
 
         // Test serialization as Event
         String json = JsonUtil.toJson((Event) originalEvent);
-        assertTrue(json.contains("\"kind\":\"status-update\""), "JSON should contain status-update kind");
+        assertTrue(json.contains("\"statusUpdate\""), "JSON should contain statusUpdate wrapper");
         assertTrue(json.contains("\"taskId\":\"test-task-abc\""), "JSON should contain task ID");
         assertTrue(json.contains("\"final\":true"), "JSON should contain final flag");
 
@@ -148,7 +148,7 @@ public void testTaskArtifactUpdateEventSerialization() throws JsonProcessingExce
 
         // Test serialization as Event
         String json = JsonUtil.toJson((Event) originalEvent);
-        assertTrue(json.contains("\"kind\":\"artifact-update\""), "JSON should contain artifact-update kind");
+        assertTrue(json.contains("\"artifactUpdate\""), "JSON should contain artifactUpdate wrapper");
         assertTrue(json.contains("\"taskId\":\"test-task-xyz\""), "JSON should contain task ID");
         assertTrue(json.contains("\"test-artifact-123\""), "JSON should contain artifact ID");
 
@@ -216,7 +216,7 @@ public void testReplicatedEventWithStreamingEventSerialization() throws JsonProc
         String json = JsonUtil.toJson(originalReplicatedEvent);
         assertTrue(json.contains("\"taskId\":\"replicated-test-task\""), "JSON should contain task ID");
         assertTrue(json.contains("\"event\""), "JSON should contain event field");
-        assertTrue(json.contains("\"kind\":\"status-update\""), "JSON should contain the event kind");
+        assertTrue(json.contains("\"statusUpdate\""), "JSON should contain the event type wrapper");
         assertFalse(json.contains("\"error\""), "JSON should not contain error field");
 
         // Deserialize the ReplicatedEventQueueItem

extras/queue-manager-replicated/core/src/test/java/io/a2a/extras/queuemanager/replicated/core/ReplicatedQueueManagerTest.java

@@ -203,7 +203,7 @@ void testReplicatedEventJsonSerialization() throws Exception {
         assertNotNull(json);
         assertTrue(json.contains("json-test-task"));
         assertTrue(json.contains("\"event\":{"));
-        assertTrue(json.contains("\"kind\":\"status-update\""));
+        assertTrue(json.contains("\"statusUpdate\""));
 
         // Deserialize back
         ReplicatedEventQueueItem deserialized = JsonUtil.fromJson(json, ReplicatedEventQueueItem.class);

extras/queue-manager-replicated/tests-single-instance/src/test/java/io/a2a/extras/queuemanager/replicated/tests/KafkaReplicationIntegrationTest.java

@@ -177,7 +177,7 @@ public void testA2AMessageReplicatedToKafka() throws Exception {
         assertEquals(contextId, statusUpdateEvent.contextId(), "Event context ID should match original context ID");
         assertEquals(TaskState.SUBMITTED, statusUpdateEvent.status().state(), "Event should show SUBMITTED state");
         assertFalse(statusUpdateEvent.isFinal(), "Event should show final:false");
-        assertEquals("status-update", statusUpdateEvent.kind(), "Event should indicate status-update type");
+        assertEquals(TaskStatusUpdateEvent.STREAMING_EVENT_ID, statusUpdateEvent.kind(), "Event should indicate status-update type");
     }
 
     @Test

extras/queue-manager-replicated/tests-single-instance/src/test/java/io/a2a/extras/queuemanager/replicated/tests/ReplicationTestAgentExecutor.java

@@ -68,7 +68,7 @@ private String getLastTextPart(Message message) throws JSONRPCError {
             throw new InvalidRequestError("No parts in message");
         }
         Part<?> part = message.parts().get(message.parts().size() - 1);
-        if (part.getKind() == Part.Kind.TEXT) {
+        if (part instanceof TextPart) {
             return ((TextPart) part).text();
         }
         throw new InvalidRequestError("Last part is not text");

extras/task-store-database-jpa/src/test/java/io/a2a/extras/taskstore/database/jpa/JpaDatabaseTaskStoreTestAgentExecutor.java

@@ -56,7 +56,7 @@ public void cancel(RequestContext context, EventQueue eventQueue) throws JSONRPC
 
     private String getLastTextPart(Message message) throws JSONRPCError {
         Part<?> part = message.parts().get(message.parts().size() - 1);
-        if (part.getKind() == Part.Kind.TEXT) {
+        if (part instanceof TextPart) {
             return ((TextPart) part).text();
         }
         throw new InvalidRequestError("No parts");