gh-135532: use defining_class for copying BLAKE-2 and SHA-3 objects

Lib/test/test_hashlib.py

@@ -371,6 +371,16 @@ def test_get_builtin_constructor(self):
         self.assertIs(constructor, _md5.md5)
         self.assertEqual(sorted(builtin_constructor_cache), ['MD5', 'md5'])
 
+    def test_copy(self):
+        for cons in self.hash_constructors:
+            h1 = cons(os.urandom(16), usedforsecurity=False)
+            h2 = h1.copy()
+            self.assertIs(type(h1), type(h2))
+            self.assertEqual(h1.name, h2.name)
+            size = (16,) if h1.name in self.shakes else ()
+            self.assertEqual(h1.digest(*size), h2.digest(*size))
+            self.assertEqual(h1.hexdigest(*size), h2.hexdigest(*size))
+
     def test_hexdigest(self):
         for cons in self.hash_constructors:
             h = cons(usedforsecurity=False)

Modules/blake2module.c

@@ -787,17 +787,19 @@ blake2_blake2b_copy_unlocked(Blake2Object *self, Blake2Object *cpy)
 /*[clinic input]
 _blake2.blake2b.copy
 
+    cls: defining_class
+
 Return a copy of the hash object.
 [clinic start generated code]*/
 
 static PyObject *
-_blake2_blake2b_copy_impl(Blake2Object *self)
-/*[clinic end generated code: output=622d1c56b91c50d8 input=e383c2d199fd8a2e]*/
+_blake2_blake2b_copy_impl(Blake2Object *self, PyTypeObject *cls)
+/*[clinic end generated code: output=5f8ea31c56c52287 input=f38f3475e9aec98d]*/
 {
     int rc;
     Blake2Object *cpy;
 
-    if ((cpy = new_Blake2Object(Py_TYPE(self))) == NULL) {
+    if ((cpy = new_Blake2Object(cls)) == NULL) {
         return NULL;
     }
 

Modules/sha3module.c

@@ -239,16 +239,17 @@ SHA3_traverse(PyObject *self, visitproc visit, void *arg)
 /*[clinic input]
 _sha3.sha3_224.copy
 
+    cls: defining_class
+
 Return a copy of the hash object.
 [clinic start generated code]*/
 
 static PyObject *
-_sha3_sha3_224_copy_impl(SHA3object *self)
-/*[clinic end generated code: output=6c537411ecdcda4c input=93a44aaebea51ba8]*/
+_sha3_sha3_224_copy_impl(SHA3object *self, PyTypeObject *cls)
+/*[clinic end generated code: output=13958b44c244013e input=7134b4dc0a2fbcac]*/
 {
     SHA3object *newobj;
-
-    if ((newobj = newSHA3object(Py_TYPE(self))) == NULL) {
+    if ((newobj = newSHA3object(cls)) == NULL) {
         return NULL;
     }
     HASHLIB_ACQUIRE_LOCK(self);