Fix #16759. Convert DWORD registry values using unsigned long.

When converting REG_DWORD registry values into Python, the conversion
needs to be made from an *unsigned* long (k instead of i) to match the
DWORD type.

Lib/test/test_winreg.py

@@ -326,6 +326,23 @@ class LocalWinregTests(BaseWinregTests):
         finally:
             DeleteKey(HKEY_CURRENT_USER, test_key_name)
 
+    def test_queryvalueex_return_value(self):
+        # Test for Issue #16759, return unsigned int from QueryValueEx.
+        # Reg2Py, which gets called by QueryValueEx, was returning a value
+        # generated by PyLong_FromLong. The implmentation now uses
+        # PyLong_FromUnsignedLong to match DWORD's size.
+        try:
+            with CreateKey(HKEY_CURRENT_USER, test_key_name) as ck:
+                self.assertNotEqual(ck.handle, 0)
+                test_val = 0x80000000
+                SetValueEx(ck, "test_name", None, REG_DWORD, test_val)
+                ret_val, ret_type = QueryValueEx(ck, "test_name")
+                self.assertEqual(ret_type, REG_DWORD)
+                self.assertEqual(ret_val, test_val)
+        finally:
+            DeleteKey(HKEY_CURRENT_USER, test_key_name)
+
+
 
 @unittest.skipUnless(REMOTE_NAME, "Skipping remote registry tests")
 class RemoteWinregTests(BaseWinregTests):

Misc/NEWS

@@ -9,6 +9,10 @@ What's New in Python 2.7.4
 Core and Builtins
 -----------------
 
+- Issue #16759: Support the full DWORD (unsigned long) range in Reg2Py
+  when retreiving a REG_DWORD value. This corrects functions like
+  winreg.QueryValueEx that may have been returning truncated values.
+
 - Issue #14420: Support the full DWORD (unsigned long) range in Py2Reg
   when passed a REG_DWORD value. Fixes ValueError in winreg.SetValueEx when
   given a long.

PC/_winreg.c

@@ -918,9 +918,9 @@ Reg2Py(char *retDataBuf, DWORD retDataSize, DWORD typ)
     switch (typ) {
         case REG_DWORD:
             if (retDataSize == 0)
-                obData = Py_BuildValue("i", 0);
+                obData = Py_BuildValue("k", 0);
             else
-                obData = Py_BuildValue("i",
+                obData = Py_BuildValue("k",
                                        *(int *)retDataBuf);
             break;
         case REG_SZ: