gh-139122: Fix the C UUID error message for badly formed hex strings

Author: RaphaelFakhri

Lib/test/test_uuid.py

@@ -311,6 +311,22 @@ def __str__(self):
 
         self.assertEqual(repr(CustomUUID(int=1)), "CustomUUID('custom uuid')")
 
+    def test_bad_hex_error_message(self):
+        # A hex string that does not hold exactly 32 hex digits raises the
+        # same error message in the C and Python implementations.
+        for text in ('',
+                     '1234567812345678123456781234567',
+                     '123456781234567812345678123456789',
+                     '{123456781234567812345678123456789}',
+                     '12345678-1234-5678-1234-567812345678-9',
+                     '12345678-1234-5678-1234-56781234567',
+                     '12345678-1234-5678-1234-5678123456'):
+            with self.subTest(text=text):
+                with self.assertRaises(ValueError) as cm:
+                    self.uuid.UUID(text)
+                self.assertEqual(str(cm.exception),
+                                 'badly formed hexadecimal UUID string')
+
     def test_exceptions(self):
         badvalue = lambda f: self.assertRaises(ValueError, f)
         badtype = lambda f: self.assertRaises(TypeError, f)

Modules/_uuidmodule.c

@@ -738,17 +738,19 @@ from_hex(uuidobject *self, PyObject *hex)
         }
 
         if (j > UUID_SIZE || (j == UUID_SIZE && acc_set)) {
-            PyErr_Format(PyExc_ValueError,
-                "invalid UUID '%s': decodes to more than 16 bytes",
-                hex);
+            PyErr_SetString(
+                PyExc_ValueError,
+                "badly formed hexadecimal UUID string"
+            );
             return -1;
         }
     }
 
     if (j != UUID_SIZE) {
-        PyErr_Format(PyExc_ValueError,
-            "invalid UUID '%s': decodes to less than 16 bytes",
-            hex);
+        PyErr_SetString(
+            PyExc_ValueError,
+            "badly formed hexadecimal UUID string"
+        );
         return -1;
     }