Handle IPC receive socket construction failures safely

source/extensions/isaacsim.examples.ipc/python/nodes/OgnSimpleReceiveExternalStepPy.py

@@ -82,14 +82,16 @@ def compute(db: object) -> bool:
                 port = int(port_str)
             except ValueError:
                 return False
+            ls = None
             try:
                 ls = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                 ls.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
                 ls.bind((host, port))
                 ls.listen(1)
                 ls.setblocking(False)  # non-blocking so accept() returns immediately when no client is waiting
             except OSError:
-                ls.close()
+                if ls is not None:
+                    ls.close()
                 return False
             state.listen_sock = ls
             state.uri = uri

source/extensions/isaacsim.examples.ipc/python/tests/test_receive_external_step_socket_failure.py

@@ -0,0 +1,43 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Regression coverage for TCP receive socket-construction failures."""
+
+import importlib.util
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import patch
+
+import omni.kit.test
+
+
+_MODULE_PATH = Path(__file__).resolve().parents[1] / "nodes" / "OgnSimpleReceiveExternalStepPy.py"
+_SPEC = importlib.util.spec_from_file_location("_ogn_receive_external_step_test", _MODULE_PATH)
+_MODULE = importlib.util.module_from_spec(_SPEC)
+assert _SPEC.loader is not None
+_SPEC.loader.exec_module(_MODULE)
+
+
+class TestReceiveExternalStepSocketFailure(omni.kit.test.AsyncTestCase):
+    """Verify socket creation failures return False without secondary exceptions."""
+
+    async def test_socket_constructor_failure_does_not_reference_unassigned_socket(self) -> None:
+        state = _MODULE.OgnSimpleReceiveExternalStepPyInternalState.__new__(
+            _MODULE.OgnSimpleReceiveExternalStepPyInternalState
+        )
+        state.listen_sock = None
+        state.client_sock = None
+        state.buf = bytearray()
+        state.uri = ""
+        db = SimpleNamespace(
+            per_instance_state=state,
+            inputs=SimpleNamespace(uri="127.0.0.1:8555"),
+            outputs=SimpleNamespace(),
+        )
+
+        with patch.object(_MODULE.socket, "socket", side_effect=OSError("socket unavailable")):
+            result = _MODULE.OgnSimpleReceiveExternalStepPy.compute(db)
+
+        self.assertFalse(result)
+        self.assertIsNone(state.listen_sock)
+        self.assertEqual(state.uri, "")