Fix BLE close() deadlock from re-entrant disconnect callback

When close() disconnects the BLE device, Bleak fires the
disconnected_callback which calls close() again. The second
close() tries to disconnect while the first is still in progress,
causing a deadlock. Add a _closing guard flag to prevent the
re-entrant call.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: ko7m

meshtastic/ble_interface.py

@@ -56,6 +56,7 @@ def __init__( # pylint: disable=R0917
         )
 
         self.should_read = False
+        self._closing = False
 
         logger.debug("Threads starting")
         self._want_receive = True
@@ -250,6 +251,10 @@ def _sendToRadioImpl(self, toRadio) -> None:
             self.should_read = True
 
     def close(self) -> None:
+        if self._closing:
+            return
+        self._closing = True
+
         try:
             MeshInterface.close(self)
         except Exception as e:

meshtastic/tests/test_ble_interface.py

@@ -1,5 +1,6 @@
 """Meshtastic unit tests for ble_interface.py"""
 
+import atexit
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -67,3 +68,31 @@ def test_ble_receive_wraps_unexpected_bleak_error_with_kind():
     with pytest.raises(BLEInterface.BLEError) as excinfo:
         iface._receiveFromRadioImpl()
     assert excinfo.value.kind == BLEInterface.BLEError.READ_ERROR
+
+
+@pytest.mark.unit
+def test_ble_close_reentrant_does_not_deadlock() -> None:
+    """close() must not deadlock when disconnect callback re-enters close()."""
+    iface = object.__new__(BLEInterface)
+    iface._closing = False
+    iface._want_receive = False
+    iface._receiveThread = None
+
+    disconnect_count = 0
+
+    def fake_disconnect():
+        nonlocal disconnect_count
+        disconnect_count += 1
+        iface.close()  # re-entrant call — should return immediately
+
+    mock_client = MagicMock()
+    mock_client.disconnect.side_effect = fake_disconnect
+    iface.client = mock_client
+    iface._exit_handler = lambda: None
+
+    with patch("meshtastic.mesh_interface.MeshInterface.close"), \
+         patch.object(iface, "_disconnected"):
+        iface.close()
+
+    assert disconnect_count == 1, "disconnect() should be called exactly once"
+    assert iface.client is None, "client should be cleaned up"