Remove pointless try/except (#2091)

pymodbus/transport/serialtransport.py

@@ -26,9 +26,8 @@ def __init__(self, loop, protocol, *args, **kwargs) -> None:
         self._poll_wait_time = 0.0005
         self.sync_serial.timeout = 0
         self.sync_serial.write_timeout = 0
-        self.future: asyncio.Task | None = None
 
-    def setup(self):
+    def setup(self) -> None:
         """Prepare to read/write."""
         if os.name == "nt" or self.force_poll:
             self.poll_task = asyncio.create_task(self.polling_task())
@@ -44,7 +43,6 @@ def close(self, exc: Exception | None = None) -> None:
         self.flush()
         if self.poll_task:
             self.poll_task.cancel()
-            self.future = asyncio.ensure_future(self.poll_task)
             self.poll_task = None
         else:
             self.async_loop.remove_reader(self.sync_serial.fileno())
@@ -147,16 +145,12 @@ def intern_write_ready(self) -> None:
 
     async def polling_task(self):
         """Poll and try to read/write."""
-        try:
-            while self.sync_serial:
-                await asyncio.sleep(self._poll_wait_time)
-                while self.intern_write_buffer:
-                    self.intern_write_ready()
-                if self.sync_serial.in_waiting:
-                    self.intern_read_ready()
-        except asyncio.CancelledError:
-            self.close(None)
-
+        while self.sync_serial:
+            await asyncio.sleep(self._poll_wait_time)
+            while self.intern_write_buffer:
+                self.intern_write_ready()
+            if self.sync_serial.in_waiting:
+                self.intern_read_ready()
 
 async def create_serial_connection(
     loop, protocol_factory, *args, **kwargs

test/transport/test_serial.py

@@ -1,5 +1,6 @@
 """Test transport."""
 import asyncio
+import contextlib
 import os
 from functools import partial
 from unittest import mock
@@ -114,7 +115,8 @@ async def test_polling(self):
         comm = SerialTransport(asyncio.get_running_loop(), mock.Mock(), "dummy")
         comm.sync_serial = mock.MagicMock()
         comm.sync_serial.read.side_effect = asyncio.CancelledError("test")
-        await comm.polling_task()
+        with contextlib.suppress(asyncio.CancelledError):
+            await comm.polling_task()
 
     @pytest.mark.skipif(os.name == "nt", reason="Windows not supported")
     async def test_poll_task(self):