[ServerCnx] Close connection after receiving unexpected SendCommand

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/ServerCnx.java

@@ -1352,7 +1352,9 @@ protected void handleSend(CommandSend send, ByteBuf headersAndPayload) {
         CompletableFuture<Producer> producerFuture = producers.get(send.getProducerId());
 
         if (producerFuture == null || !producerFuture.isDone() || producerFuture.isCompletedExceptionally()) {
-            log.warn("[{}] Producer had already been closed: {}", remoteAddress, send.getProducerId());
+            log.warn("[{}] Received message, but the producer is not ready : {}. Closing the connection.",
+                    remoteAddress, send.getProducerId());
+            close();
             return;
         }
 

pulsar-broker/src/test/java/org/apache/pulsar/broker/service/ServerCnxTest.java

@@ -648,6 +648,28 @@ public void testSendCommand() throws Exception {
         channel.finish();
     }
 
+    @Test(timeOut = 30000)
+    public void testSendCommandBeforeCreatingProducer() throws Exception {
+        resetChannel();
+        setChannelConnected();
+
+        // test SEND before producer is created
+        MessageMetadata messageMetadata = new MessageMetadata()
+                .setPublishTime(System.currentTimeMillis())
+                .setProducerName("prod-name")
+                .setSequenceId(0);
+        ByteBuf data = Unpooled.buffer(1024);
+
+        ByteBuf clientCommand = ByteBufPair.coalesce(Commands.newSend(1, 0, 1,
+                ChecksumType.None, messageMetadata, data));
+        channel.writeInbound(Unpooled.copiedBuffer(clientCommand));
+        clientCommand.release();
+
+        // Then expect channel to close
+        Awaitility.await().atMost(10, TimeUnit.SECONDS).until(() -> !channel.isActive());
+        channel.finish();
+    }
+
     @Test(timeOut = 30000)
     public void testUseSameProducerName() throws Exception {
         resetChannel();