gh-128889: Zero out memory ctypes for generated struct layout tests (G…

…H-128944)
python · Jan 21, 2025 · 13475e0 · 13475e0
1 parent 4b37a6b
commit 13475e0
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Showing 2 changed files with 147 additions and 74 deletions.
diff --git a/Lib/test/test_ctypes/test_generated_structs.py b/Lib/test/test_ctypes/test_generated_structs.py
@@ -443,7 +443,7 @@ def test_generated_data(self):
         - None
         - reason to skip the test (str)
 
-        This does depend on the C compiler keeping padding bits zero.
+        This does depend on the C compiler keeping padding bits unchanged.
         Common compilers seem to do so.
         """
         for name, cls in TESTCASES.items():
@@ -696,7 +696,8 @@ def output(string):
             output('                ' + line)
         typename = f'{struct_or_union(cls)} {name}'
         output(f"""
-                {typename} value = {{0}};
+                {typename} value;
+                memset(&value, 0, sizeof(value));
                 APPEND(PyUnicode_FromString({c_str_repr(name)}));
                 APPEND(PyLong_FromLong(sizeof({typename})));
                 APPEND(PyLong_FromLong(_Alignof({typename})));