From f0051cedcb17fbeb90dcbfa09e7496d3e834b00f Mon Sep 17 00:00:00 2001
From: Jan Christoph Bernack <jc.bernack@gmail.com>
Date: Sat, 7 Mar 2026 03:05:49 +0100
Subject: [PATCH 1/2] fix piggybacked CoAP response

---
 .../client/CoapClientIntegrationTest.java     | 19 ++++++++++++++++---
 .../callback/AbstractSyncSessionCallback.java |  1 -
 .../coap/callback/CoapResponseCallback.java   |  5 -----
 .../callback/CoapResponseCodeCallback.java    |  8 +-------
 4 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java
index 12b2b677d4..75f49804e2 100644
--- a/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java
+++ b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java
@@ -100,7 +100,7 @@ public class CoapClientIntegrationTest extends AbstractCoapIntegrationTest {
         client = createClientForFeatureWithConfirmableParameter(FeatureType.ATTRIBUTES, confirmable);
         CoapResponse coapResponse = client.postMethod(PAYLOAD_VALUES_STR.getBytes());
         assertEquals(CoAP.ResponseCode.CREATED, coapResponse.getCode());
-        assertEquals("CoAP response type is wrong!", client.getType(), coapResponse.advanced().getType());
+        assertValidResponseType(client.getType(), coapResponse.advanced().getType());
 
         DeviceId deviceId = savedDevice.getId();
         List<String> actualKeys = getActualKeysList(deviceId);
@@ -184,7 +184,7 @@ public class CoapClientIntegrationTest extends AbstractCoapIntegrationTest {
         String featureTokenUrl = CoapTestClient.getFeatureTokenUrl(accessToken, FeatureType.ATTRIBUTES) + "?clientKeys=" + keysParam + "&sharedKeys=" + keysParam;
         client.setURI(featureTokenUrl);
         CoapResponse response = client.getMethod();
-        assertEquals("CoAP response type is wrong!", client.getType(), response.advanced().getType());
+        assertValidResponseType(client.getType(), response.advanced().getType());
     }
 
     @SuppressWarnings({"unchecked", "rawtypes"})
@@ -260,7 +260,7 @@ public class CoapClientIntegrationTest extends AbstractCoapIntegrationTest {
             payloadBytes = response.getPayload();
             responseCode = response.getCode();
             observe = response.getOptions().getObserve();
-            wasSuccessful = client.getType().equals(response.advanced().getType());
+            wasSuccessful = isValidResponseType(client.getType(), response.advanced().getType());
             if (observe != null) {
                 if (observe > 0) {
                     processOnLoadResponse(response, client);
@@ -304,4 +304,17 @@ public class CoapClientIntegrationTest extends AbstractCoapIntegrationTest {
     private List<EntityKey> getEntityKeys(EntityKeyType scope) {
         return CoapClientIntegrationTest.EXPECTED_KEYS.stream().map(key -> new EntityKey(scope, key)).collect(Collectors.toList());
     }
+
+    private static void assertValidResponseType(CoAP.Type requestType, CoAP.Type responseType) {
+        assertTrue("Unexpected CoAP response type " + responseType + " for request type " + requestType,
+                isValidResponseType(requestType, responseType));
+    }
+
+    private static boolean isValidResponseType(CoAP.Type requestType, CoAP.Type responseType) {
+        return switch (requestType) {
+            case CON -> CoAP.Type.ACK.equals(responseType) || CoAP.Type.CON.equals(responseType) || CoAP.Type.NON.equals(responseType);
+            case NON -> CoAP.Type.NON.equals(responseType) || CoAP.Type.CON.equals(responseType);
+            default -> false;
+        };
+    }
 }
diff --git a/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/AbstractSyncSessionCallback.java b/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/AbstractSyncSessionCallback.java
index bf23ea6766..6fa56dbd47 100644
--- a/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/AbstractSyncSessionCallback.java
+++ b/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/AbstractSyncSessionCallback.java
@@ -87,7 +87,6 @@ public abstract class AbstractSyncSessionCallback implements SessionMsgListener
 
     protected void respond(Response response) {
         response.getOptions().setContentFormat(TbCoapContentFormatUtil.getContentFormat(exchange.getRequestOptions().getContentFormat(), state.getContentFormat()));
-        response.setConfirmable(exchange.advanced().getRequest().isConfirmable());
         exchange.respond(response);
     }
 
diff --git a/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCallback.java b/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCallback.java
index c3f70ce0d7..2502f40bfc 100644
--- a/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCallback.java
+++ b/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCallback.java
@@ -36,7 +36,6 @@ public class CoapResponseCallback implements TransportServiceCallback<Void> {
      */
     @Override
     public void onSuccess(Void msg) {
-        this.onSuccessResponse.setConfirmable(isConRequest());
         exchange.respond(this.onSuccessResponse);
     }
 
@@ -47,8 +46,4 @@ public class CoapResponseCallback implements TransportServiceCallback<Void> {
     public void onError(Throwable e) {
         exchange.respond(onFailureResponse);
     }
-
-    protected boolean isConRequest() {
-        return exchange.advanced().getRequest().isConfirmable();
-    }
 }
diff --git a/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCodeCallback.java b/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCodeCallback.java
index 2bfa172bc7..b114ddec2d 100644
--- a/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCodeCallback.java
+++ b/common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapResponseCodeCallback.java
@@ -34,17 +34,11 @@ public class CoapResponseCodeCallback implements TransportServiceCallback<Void>
 
     @Override
     public void onSuccess(Void msg) {
-        Response response = new Response(onSuccessResponse);
-        response.setConfirmable(isConRequest());
-        exchange.respond(response);
+        exchange.respond(new Response(onSuccessResponse));
     }
 
     @Override
     public void onError(Throwable e) {
         exchange.respond(onFailureResponse);
     }
-
-    protected boolean isConRequest() {
-        return exchange.advanced().getRequest().isConfirmable();
-    }
 }

From 38d59e0fce3716d73e1b8c48ccab1569995edda2 Mon Sep 17 00:00:00 2001
From: Jan Christoph Bernack <jc.bernack@gmail.com>
Date: Sun, 8 Mar 2026 00:15:37 +0100
Subject: [PATCH 2/2] add tests for piggybacked CoAP responses

---
 .../coap/AbstractCoapIntegrationTest.java     | 11 ++++
 ...tCoapClientPiggybackedIntegrationTest.java | 52 +++++++++++++++++++
 .../client/CoapClientIntegrationTest.java     | 15 ++----
 .../CoapClientNoPiggybackIntegrationTest.java | 40 ++++++++++++++
 .../CoapClientPiggybackedIntegrationTest.java | 40 ++++++++++++++
 5 files changed, 146 insertions(+), 12 deletions(-)
 create mode 100644 application/src/test/java/org/thingsboard/server/transport/coap/client/AbstractCoapClientPiggybackedIntegrationTest.java
 create mode 100644 application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientNoPiggybackIntegrationTest.java
 create mode 100644 application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientPiggybackedIntegrationTest.java

diff --git a/application/src/test/java/org/thingsboard/server/transport/coap/AbstractCoapIntegrationTest.java b/application/src/test/java/org/thingsboard/server/transport/coap/AbstractCoapIntegrationTest.java
index 69d40f5409..1a2f4f1d02 100644
--- a/application/src/test/java/org/thingsboard/server/transport/coap/AbstractCoapIntegrationTest.java
+++ b/application/src/test/java/org/thingsboard/server/transport/coap/AbstractCoapIntegrationTest.java
@@ -42,6 +42,7 @@ import org.thingsboard.server.common.data.device.profile.JsonTransportPayloadCon
 import org.thingsboard.server.common.data.device.profile.ProtoTransportPayloadConfiguration;
 import org.thingsboard.server.common.data.device.profile.TransportPayloadTypeConfiguration;
 import org.thingsboard.server.common.data.security.DeviceCredentials;
+import org.thingsboard.server.common.msg.session.FeatureType;
 import org.thingsboard.server.transport.AbstractTransportIntegrationTest;
 import org.thingsboard.server.utils.PortFinder;
 
@@ -176,4 +177,14 @@ public abstract class AbstractCoapIntegrationTest extends AbstractTransportInteg
         device.setType(type);
         return doPost("/api/device", device, Device.class);
     }
+
+    protected CoapTestClient createClientForFeatureWithConfirmableParameter(FeatureType featureType, boolean confirmable) {
+        CoapTestClient coapTestClient = new CoapTestClient(accessToken, featureType);
+        if (confirmable) {
+            coapTestClient.useCONs();
+        } else {
+            coapTestClient.useNONs();
+        }
+        return coapTestClient;
+    }
 }
diff --git a/application/src/test/java/org/thingsboard/server/transport/coap/client/AbstractCoapClientPiggybackedIntegrationTest.java b/application/src/test/java/org/thingsboard/server/transport/coap/client/AbstractCoapClientPiggybackedIntegrationTest.java
new file mode 100644
index 0000000000..32b7e9dc80
--- /dev/null
+++ b/application/src/test/java/org/thingsboard/server/transport/coap/client/AbstractCoapClientPiggybackedIntegrationTest.java
@@ -0,0 +1,52 @@
+/**
+ * Copyright © 2016-2026 The Thingsboard Authors
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 org.thingsboard.server.transport.coap.client;
+
+import lombok.extern.slf4j.Slf4j;
+import org.eclipse.californium.core.CoapResponse;
+import org.eclipse.californium.core.coap.CoAP;
+import org.junit.After;
+import org.junit.Before;
+import org.thingsboard.server.common.msg.session.FeatureType;
+import org.thingsboard.server.transport.coap.AbstractCoapIntegrationTest;
+import org.thingsboard.server.transport.coap.CoapTestConfigProperties;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+@Slf4j
+public abstract class AbstractCoapClientPiggybackedIntegrationTest extends AbstractCoapIntegrationTest {
+
+    @Before
+    public void beforeTest() throws Exception {
+        CoapTestConfigProperties configProperties = CoapTestConfigProperties.builder()
+                .deviceName("CoAP Message Flow Piggyback Device")
+                .build();
+        processBeforeTest(configProperties);
+    }
+
+    @After
+    public void afterTest() throws Exception {
+        processAfterTest();
+    }
+
+    protected void testCase(boolean confirmable, CoAP.Type expectedResponseType) throws Exception {
+        client = createClientForFeatureWithConfirmableParameter(FeatureType.ATTRIBUTES, confirmable);
+        CoapResponse response = client.postMethod(PAYLOAD_VALUES_STR);
+        assertNotNull(response);
+        assertEquals(expectedResponseType, response.advanced().getType());
+    }
+}
diff --git a/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java
index 75f49804e2..a128710078 100644
--- a/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java
+++ b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientIntegrationTest.java
@@ -5,7 +5,7 @@
  * 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
+ * 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,
@@ -291,16 +291,6 @@ public class CoapClientIntegrationTest extends AbstractCoapIntegrationTest {
         }, DEVICE_RESPONSE, MediaTypeRegistry.APPLICATION_JSON);
     }
 
-    private CoapTestClient createClientForFeatureWithConfirmableParameter(FeatureType featureType, boolean confirmable) {
-        CoapTestClient coapTestClient = new CoapTestClient(accessToken, featureType);
-        if (confirmable) {
-            coapTestClient.useCONs();
-        } else {
-            coapTestClient.useNONs();
-        }
-        return coapTestClient;
-    }
-
     private List<EntityKey> getEntityKeys(EntityKeyType scope) {
         return CoapClientIntegrationTest.EXPECTED_KEYS.stream().map(key -> new EntityKey(scope, key)).collect(Collectors.toList());
     }
@@ -312,7 +302,8 @@ public class CoapClientIntegrationTest extends AbstractCoapIntegrationTest {
 
     private static boolean isValidResponseType(CoAP.Type requestType, CoAP.Type responseType) {
         return switch (requestType) {
-            case CON -> CoAP.Type.ACK.equals(responseType) || CoAP.Type.CON.equals(responseType) || CoAP.Type.NON.equals(responseType);
+            case CON ->
+                    CoAP.Type.ACK.equals(responseType) || CoAP.Type.CON.equals(responseType) || CoAP.Type.NON.equals(responseType);
             case NON -> CoAP.Type.NON.equals(responseType) || CoAP.Type.CON.equals(responseType);
             default -> false;
         };
diff --git a/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientNoPiggybackIntegrationTest.java b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientNoPiggybackIntegrationTest.java
new file mode 100644
index 0000000000..53939f84e3
--- /dev/null
+++ b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientNoPiggybackIntegrationTest.java
@@ -0,0 +1,40 @@
+/**
+ * Copyright © 2016-2026 The Thingsboard Authors
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 org.thingsboard.server.transport.coap.client;
+
+import lombok.extern.slf4j.Slf4j;
+import org.eclipse.californium.core.coap.CoAP;
+import org.junit.Test;
+import org.springframework.test.context.TestPropertySource;
+import org.thingsboard.server.dao.service.DaoSqlTest;
+
+@Slf4j
+@DaoSqlTest
+@TestPropertySource(properties = {
+        "transport.coap.piggyback_timeout=0"
+})
+public class CoapClientNoPiggybackIntegrationTest extends AbstractCoapClientPiggybackedIntegrationTest {
+    @Test
+    public void testConfirmable() throws Exception {
+        // response should be sent via seperate CON transaction (not piggybacked)
+        testCase(true, CoAP.Type.CON);
+    }
+
+    @Test
+    public void testNonConfirmable() throws Exception {
+        testCase(false, CoAP.Type.NON);
+    }
+}
diff --git a/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientPiggybackedIntegrationTest.java b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientPiggybackedIntegrationTest.java
new file mode 100644
index 0000000000..68f28ce4db
--- /dev/null
+++ b/application/src/test/java/org/thingsboard/server/transport/coap/client/CoapClientPiggybackedIntegrationTest.java
@@ -0,0 +1,40 @@
+/**
+ * Copyright © 2016-2026 The Thingsboard Authors
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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 org.thingsboard.server.transport.coap.client;
+
+import lombok.extern.slf4j.Slf4j;
+import org.eclipse.californium.core.coap.CoAP;
+import org.junit.Test;
+import org.springframework.test.context.TestPropertySource;
+import org.thingsboard.server.dao.service.DaoSqlTest;
+
+@Slf4j
+@DaoSqlTest
+@TestPropertySource(properties = {
+        "transport.coap.piggyback_timeout=2000"
+})
+public class CoapClientPiggybackedIntegrationTest extends AbstractCoapClientPiggybackedIntegrationTest {
+    @Test
+    public void testConfirmable() throws Exception {
+        // response should be included in the ACK packet (piggybacked)
+        testCase(true, CoAP.Type.ACK);
+    }
+
+    @Test
+    public void testNonConfirmable() throws Exception {
+        testCase(false, CoAP.Type.NON);
+    }
+}