Add ENETUNREACH to non-retryable errors in XorTransport (#1668)

`ENETUNREACH` is semantically equivalent to `EHOSTUNREACH` (which is
already in `_NO_RETRY_ERRORS`) — both indicate the destination cannot be
reached at the network layer. Retrying immediately will not resolve the
condition.

In containerized environments (e.g., Home Assistant running in Docker
with bridge networking), a single ICMP "Network unreachable" response
can temporarily poison the container's routing cache. The unnecessary
retries reinforce the poisoned cache entry, causing cascading failures
for other devices on the same subnet.

kasa/transports/xortransport.py

@@ -29,7 +29,12 @@ from kasa.json import loads as json_loads
 from .basetransport import BaseTransport
 
 _LOGGER = logging.getLogger(__name__)
-_NO_RETRY_ERRORS = {errno.EHOSTDOWN, errno.EHOSTUNREACH, errno.ECONNREFUSED}
+_NO_RETRY_ERRORS = {
+    errno.EHOSTDOWN,
+    errno.EHOSTUNREACH,
+    errno.ENETUNREACH,
+    errno.ECONNREFUSED,
+}
 _UNSIGNED_INT_NETWORK_ORDER = struct.Struct(">I")
 
 

tests/protocols/test_iotprotocol.py

@@ -807,10 +807,17 @@ async def test_transport_credentials_hash_from_config(mocker, transport_class):
     [
         (ConnectionRefusedError("dummy exception"), False),
         (OSError(errno.EHOSTDOWN, os.strerror(errno.EHOSTDOWN)), False),
+        (OSError(errno.ENETUNREACH, os.strerror(errno.ENETUNREACH)), False),
         (OSError(errno.ECONNRESET, os.strerror(errno.ECONNRESET)), True),
         (Exception("dummy exception"), True),
     ],
-    ids=("ConnectionRefusedError", "OSErrorNoRetry", "OSErrorRetry", "Exception"),
+    ids=(
+        "ConnectionRefusedError",
+        "OSErrorHostDown",
+        "OSErrorNetUnreach",
+        "OSErrorRetry",
+        "Exception",
+    ),
 )
 @pytest.mark.parametrize(
     ("protocol_class", "transport_class"),