fix: source _RECENT_PACKETS_MAX from const so cdef restores C-int compare

bluetoothbot · bluetoothbot · commit a25e05c28e0b · 2026-05-20T02:59:43.000Z
diff --git a/src/zeroconf/_listener.pxd b/src/zeroconf/_listener.pxd
@@ -13,6 +13,7 @@ cdef object DEBUG_ENABLED
 cdef bint TYPE_CHECKING
 
 cdef cython.uint _MAX_MSG_ABSOLUTE
+cdef cython.uint _RECENT_PACKETS_MAX
 
 
 cdef class AsyncListener:
diff --git a/src/zeroconf/_listener.py b/src/zeroconf/_listener.py
@@ -32,18 +32,18 @@
 from ._protocol.incoming import DNSIncoming
 from ._transport import _WrappedTransport, make_wrapped_transport
 from ._utils.time import current_time_millis, millis_to_seconds
-from .const import _DUPLICATE_PACKET_SUPPRESSION_INTERVAL, _MAX_MSG_ABSOLUTE
+from .const import _DUPLICATE_PACKET_SUPPRESSION_INTERVAL, _MAX_MSG_ABSOLUTE, _RECENT_PACKETS_MAX
 
 if TYPE_CHECKING:
     from ._core import Zeroconf
 
 _TC_DELAY_RANDOM_INTERVAL = (400, 500)
 
-# Bounded recency window so an alternating (A, B, A, B, ...) flood can't
-# slip past single-slot dedup. State lives on the listener (one per
-# interface) so a duplicate seen on one interface does not suppress a
-# legitimate QU / unicast reply that arrives on a different interface.
-_RECENT_PACKETS_MAX = 16
+# Bounded recency window (`_RECENT_PACKETS_MAX`, imported from `.const`)
+# so an alternating (A, B, A, B, ...) flood can't slip past single-slot
+# dedup. State lives on the listener (one per interface) so a duplicate
+# seen on one interface does not suppress a legitimate QU / unicast
+# reply that arrives on a different interface.
 
 
 _bytes = bytes
diff --git a/src/zeroconf/const.py b/src/zeroconf/const.py
@@ -33,6 +33,7 @@
 _LISTENER_TIME = 200  # ms
 _BROWSER_TIME = 10000  # ms
 _DUPLICATE_PACKET_SUPPRESSION_INTERVAL = 1000  # ms
+_RECENT_PACKETS_MAX = 16  # Bounded recency window for per-listener dedup
 _DUPLICATE_QUESTION_INTERVAL = 999  # ms # Must be 1ms less than _DUPLICATE_PACKET_SUPPRESSION_INTERVAL
 _CACHE_CLEANUP_INTERVAL = 10  # s
 _LOADED_SYSTEM_TIMEOUT = 10  # s
diff --git a/tests/test_listener.py b/tests/test_listener.py
@@ -365,7 +365,7 @@ def handle_query_or_defer(
     now = current_time_millis()
 
     packets = []
-    for i in range(_listener._RECENT_PACKETS_MAX + 4):
+    for i in range(const._RECENT_PACKETS_MAX + 4):
         query = r.DNSOutgoing(const._FLAGS_QR_QUERY, multicast=True)
         query.add_question(r.DNSQuestion(f"n{i}._http._tcp.local.", const._TYPE_PTR, const._CLASS_IN))
         packets.append(query.packets()[0])
@@ -377,7 +377,7 @@ def handle_query_or_defer(
         _handle_query_or_defer.reset_mock()
 
         # The oldest packets should have been evicted and now replay.
-        evicted = packets[: len(packets) - _listener._RECENT_PACKETS_MAX]
+        evicted = packets[: len(packets) - const._RECENT_PACKETS_MAX]
         for packet in evicted:
             listener._process_datagram_at_time(False, len(packet), now, packet, addrs)
         assert _handle_query_or_defer.call_count == len(evicted)
