Router: fixing crash after WebSocket processing.

After WebSocket processing, the application port was released with incorrect
reason ("got request"), unnecessarily decrementing the active request counter.

The assertion was triggered only on application removal; a test was added
for this case.

docs/changes.xml

@@ -97,6 +97,13 @@ a memory leak occurring in the router process when serving a file larger than
 </para>
 </change>
 
+<change type="bugfix">
+<para>
+the router process could crash while removing or reconfiguring an application
+that uses WebSocket.
+</para>
+</change>
+
 </changes>
 
 

src/nxt_router.c

@@ -3796,7 +3796,10 @@ nxt_router_response_ready_handler(nxt_task_t *task, nxt_port_recv_msg_t *msg,
         nxt_buf_chain_add(&b, nxt_http_buf_last(r));
 
         req_rpc_data->rpc_cancel = 0;
-        req_rpc_data->apr_action = NXT_APR_GOT_RESPONSE;
+
+        if (req_rpc_data->apr_action == NXT_APR_REQUEST_FAILED) {
+            req_rpc_data->apr_action = NXT_APR_GOT_RESPONSE;
+        }
 
         nxt_request_rpc_data_unlink(task, req_rpc_data);
 

test/test_asgi_websockets.py

@@ -63,6 +63,9 @@ class TestASGIWebsockets(TestApplicationPython):
             key
         ), 'key'
 
+        # remove "mirror" application
+        self.load('websockets/subprotocol')
+
     def test_asgi_websockets_subprotocol(self):
         self.load('websockets/subprotocol')
 
@@ -92,6 +95,27 @@ class TestASGIWebsockets(TestApplicationPython):
 
         sock.close()
 
+    def test_asgi_websockets_mirror_app_change(self):
+        self.load('websockets/mirror')
+
+        message = 'blah'
+
+        _, sock, _ = self.ws.upgrade()
+
+        self.ws.frame_write(sock, self.ws.OP_TEXT, message)
+        frame = self.ws.frame_read(sock)
+
+        assert message == frame['data'].decode('utf-8'), 'mirror'
+
+        self.load('websockets/subprotocol')
+
+        self.ws.frame_write(sock, self.ws.OP_TEXT, message)
+        frame = self.ws.frame_read(sock)
+
+        assert message == frame['data'].decode('utf-8'), 'mirror 2'
+
+        sock.close()
+
     def test_asgi_websockets_no_mask(self):
         self.load('websockets/mirror')