Auto fill device ids for clients. (#2372)

pymodbus/framer/base.py

@@ -69,12 +69,14 @@ def specific_decode(self, data: bytes, data_len: int) -> tuple[int, bytes]:
         return data_len, data
 
 
-    def encode(self, pdu: bytes, _dev_id: int, _tid: int) -> bytes:
+    def encode(self, pdu: bytes, dev_id: int, _tid: int) -> bytes:
         """Encode ADU.
 
         returns:
             modbus ADU (bytes)
         """
+        if dev_id and dev_id not in self.dev_ids:
+            self.dev_ids.append(dev_id)
         return pdu
 
     def buildPacket(self, message: ModbusRequest | ModbusResponse) -> bytes:

test/framers/test_framer.py

@@ -31,6 +31,9 @@ def test_base(self):
         framer = FramerBase(ClientDecoder(), [])
         framer.decode(b'')
         framer.encode(b'', 0, 0)
+        dev_id = 2
+        framer.encode(b'', dev_id, 0)
+        assert dev_id in framer.dev_ids
 
     @pytest.mark.parametrize(("entry"), list(FramerType))
     async def test_framer_init(self, test_framer):
@@ -373,4 +376,3 @@ def test_specific_decode(self, test_framer):
         res_len, res_data = test_framer.specific_decode(msg, 0)
         assert not res_len
         assert not res_data
-