fix: handle missing parent modules in _has_module

tests/utils_/test_import_utils.py

@@ -87,11 +87,15 @@ def test_returns_false_when_find_spec_raises(self):
         """``find_spec`` itself can raise for dotted names whose parent package
         fails to import. This should be treated as the module being unavailable.
         """
-        with patch(
-            "vllm.utils.import_utils.importlib.util.find_spec",
-            side_effect=ModuleNotFoundError("No module named 'fake_parent'"),
+        with (
+            patch(
+                "vllm.utils.import_utils.importlib.util.find_spec",
+                side_effect=ModuleNotFoundError("No module named 'fake_parent'"),
+            ),
+            patch("vllm.utils.import_utils.logger.warning") as mock_warning,
         ):
             assert _has_module("fake_parent.child") is False
+            mock_warning.assert_not_called()
 
     def test_result_is_cached(self):
         """Verify the @cache decorator prevents repeated imports."""

vllm/utils/import_utils.py

@@ -401,8 +401,14 @@ def _has_module(module_name: str) -> bool:
     for the same module incur no additional overhead.
     """
     try:
-        if importlib.util.find_spec(module_name) is None:
-            return False
+        module_spec = importlib.util.find_spec(module_name)
+    except ModuleNotFoundError:
+        return False
+
+    if module_spec is None:
+        return False
+
+    try:
         importlib.import_module(module_name)
     except Exception:
         logger.warning(