ipc: Fix socket handling

Speculatively fixes #5344

qutebrowser/misc/ipc.py

@@ -356,32 +356,38 @@ class IPCServer(QObject):
 
         self.got_args.emit(args, target_arg, cwd)
 
-    @pyqtSlot()
-    def on_ready_read(self):
-        """Read json data from the client."""
+    def _get_socket(self):
+        """Get the current socket for on_ready_read."""
         if self._socket is None:  # pragma: no cover
             # This happens when doing a connection while another one is already
             # active for some reason.
             if self._old_socket is None:
-                log.ipc.warning("In on_ready_read with None socket and "
-                                "old_socket!")
-                return
-            log.ipc.debug("In on_ready_read with None socket!")
+                log.ipc.warning("In _get_socket with None socket and old_socket!")
+                return None
+            log.ipc.debug("In _get_socket with None socket!")
             socket = self._old_socket
         else:
             socket = self._socket
 
         if sip.isdeleted(socket):  # pragma: no cover
             log.ipc.warning("Ignoring deleted IPC socket")
-            return
+            return None
 
+        return socket
+
+    @pyqtSlot()
+    def on_ready_read(self):
+        """Read json data from the client."""
         self._timer.stop()
+
+        socket = self._get_socket()
         while socket is not None and socket.canReadLine():
             data = bytes(socket.readLine())
             self.got_raw.emit(data)
             log.ipc.debug("Read from socket 0x{:x}: {!r}".format(
                 id(socket), data))
             self._handle_data(data)
+            socket = self._get_socket()
 
         if self._socket is not None:
             self._timer.start()

tests/unit/misc/test_ipc.py

@@ -605,7 +605,7 @@ def test_ipcserver_socket_none_readyread(ipc_server, caplog):
     assert ipc_server._old_socket is None
     with caplog.at_level(logging.WARNING):
         ipc_server.on_ready_read()
-    msg = "In on_ready_read with None socket and old_socket!"
+    msg = "In _get_socket with None socket and old_socket!"
     assert msg in caplog.messages