Default absent CreateProcess startup attributes (#9267)

* Default missing CreateProcess startup attributes

Assisted-by: Codex:GPT-6

* Use a single platform guard for winapi tests

Assisted-by: Codex:GPT-6

extra_tests/snippets/stdlib_winapi.py

@@ -4,36 +4,86 @@ import sys
 
 from testutils import assert_raises
 
-if sys.platform == "win32":
-    import _winapi
+if sys.platform != "win32":
+    sys.exit(0)
 
-    # Every call fails before a host operation. ReportEvent overflow cases
-    # also retain an embedded NUL as an independent safety barrier.
-    assert _winapi.EVENTLOG_SUCCESS == 0
-    assert _winapi.EVENTLOG_ERROR_TYPE == 1
-    assert _winapi.EVENTLOG_WARNING_TYPE == 2
-    assert _winapi.EVENTLOG_INFORMATION_TYPE == 4
-    assert _winapi.EVENTLOG_AUDIT_SUCCESS == 8
-    assert _winapi.EVENTLOG_AUDIT_FAILURE == 16
+import _winapi
 
-    assert_raises(TypeError, _winapi.RegisterEventSource, 1, "source\0")
-    assert_raises(TypeError, _winapi.RegisterEventSource, None, 1)
-    assert_raises(TypeError, _winapi.RegisterEventSource, None, None)
-    assert_raises(ValueError, _winapi.RegisterEventSource, None, "source\0")
-    assert_raises(ValueError, _winapi.RegisterEventSource, "server\0", "source\0")
-    assert_raises(ValueError, _winapi.RegisterEventSource, "", "source\0")
-    assert_raises(TypeError, _winapi.DeregisterEventSource, "invalid handle")
-    assert_raises(TypeError, _winapi.DeregisterEventSource, None)
-    assert_raises(
-        TypeError, _winapi.ReportEvent, "invalid handle", 0, 0, 0, "message\0"
-    )
-    assert_raises(ValueError, _winapi.ReportEvent, 0, 0, 0, 0, "message\0")
-    assert_raises(TypeError, _winapi.ReportEvent, 0, 0, 0, 0, None)
-    for index, bits in ((1, 16), (2, 16), (3, 32)):
-        for invalid, exception in ((-1, ValueError), (1 << bits, OverflowError)):
-            arguments = [0, 0, 0, 0, "message\0"]
-            arguments[index] = invalid
-            assert_raises(exception, _winapi.ReportEvent, *arguments)
+# Every call fails before a host operation. ReportEvent overflow cases
+# also retain an embedded NUL as an independent safety barrier.
+assert _winapi.EVENTLOG_SUCCESS == 0
+assert _winapi.EVENTLOG_ERROR_TYPE == 1
+assert _winapi.EVENTLOG_WARNING_TYPE == 2
+assert _winapi.EVENTLOG_INFORMATION_TYPE == 4
+assert _winapi.EVENTLOG_AUDIT_SUCCESS == 8
+assert _winapi.EVENTLOG_AUDIT_FAILURE == 16
+
+assert_raises(TypeError, _winapi.RegisterEventSource, 1, "source\0")
+assert_raises(TypeError, _winapi.RegisterEventSource, None, 1)
+assert_raises(TypeError, _winapi.RegisterEventSource, None, None)
+assert_raises(ValueError, _winapi.RegisterEventSource, None, "source\0")
+assert_raises(ValueError, _winapi.RegisterEventSource, "server\0", "source\0")
+assert_raises(ValueError, _winapi.RegisterEventSource, "", "source\0")
+assert_raises(TypeError, _winapi.DeregisterEventSource, "invalid handle")
+assert_raises(TypeError, _winapi.DeregisterEventSource, None)
+assert_raises(TypeError, _winapi.ReportEvent, "invalid handle", 0, 0, 0, "message\0")
+assert_raises(ValueError, _winapi.ReportEvent, 0, 0, 0, 0, "message\0")
+assert_raises(TypeError, _winapi.ReportEvent, 0, 0, 0, 0, None)
+for index, bits in ((1, 16), (2, 16), (3, 32)):
+    for invalid, exception in ((-1, ValueError), (1 << bits, OverflowError)):
         arguments = [0, 0, 0, 0, "message\0"]
-        arguments[index] = "invalid integer"
-        assert_raises(TypeError, _winapi.ReportEvent, *arguments)
+        arguments[index] = invalid
+        assert_raises(exception, _winapi.ReportEvent, *arguments)
+    arguments = [0, 0, 0, 0, "message\0"]
+    arguments[index] = "invalid integer"
+    assert_raises(TypeError, _winapi.ReportEvent, *arguments)
+
+
+import subprocess
+
+
+class PartialStartupInfo:
+    dwFlags = 0
+
+    def __getattr__(self, name):
+        raise ValueError(name)
+
+
+for startup in (None, PartialStartupInfo()):
+    process, thread, _, _ = _winapi.CreateProcess(
+        sys.executable,
+        subprocess.list2cmdline([sys.executable, "-c", "pass"]),
+        None,
+        None,
+        False,
+        _winapi.CREATE_NO_WINDOW,
+        None,
+        None,
+        startup,
+    )
+    try:
+        status = _winapi.WaitForSingleObject(process, 10000)
+        if status != _winapi.WAIT_OBJECT_0:
+            _winapi.TerminateProcess(process, 1)
+            _winapi.WaitForSingleObject(process, 10000)
+        assert status == _winapi.WAIT_OBJECT_0
+        assert _winapi.GetExitCodeProcess(process) == 0
+    finally:
+        _winapi.CloseHandle(thread)
+        _winapi.CloseHandle(process)
+
+startup = subprocess.STARTUPINFO()
+startup.dwFlags = "invalid"
+assert_raises(
+    TypeError,
+    _winapi.CreateProcess,
+    None,
+    "invalid\0",
+    None,
+    None,
+    False,
+    0,
+    None,
+    None,
+    startup,
+)