Issue #21233: Revert bytearray(int) optimization using calloc()

Doc/whatsnew/3.5.rst

@@ -196,9 +196,8 @@ Optimizations
 
 The following performance enhancements have been added:
 
-* Construction of ``bytes(int)`` and ``bytearray(int)`` (filled by zero bytes)
-  is faster and use less memory (until the bytearray buffer is filled with
-  data) for large objects. ``calloc()`` is used instead of ``malloc()`` to
+* Construction of ``bytes(int)`` (filled by zero bytes) is faster and use less
+  memory for large objects. ``calloc()`` is used instead of ``malloc()`` to
   allocate memory for these objects.
 
 * Some operations on :class:`~ipaddress.IPv4Network` and

Misc/NEWS

@@ -26,10 +26,9 @@ Core and Builtins
   internal iteration logic.
 
 - Issue #21233: Add new C functions: PyMem_RawCalloc(), PyMem_Calloc(),
-  PyObject_Calloc(), _PyObject_GC_Calloc(). bytes(int) and bytearray(int)
-  are now using ``calloc()`` instead of ``malloc()`` for large objects which
-  is faster and use less memory (until the bytearray buffer is filled with
-  data).
+  PyObject_Calloc(), _PyObject_GC_Calloc(). bytes(int) is now using
+  ``calloc()`` instead of ``malloc()`` for large objects which is faster and
+  use less memory.
 
 - Issue #21377: PyBytes_Concat() now tries to concatenate in-place when the
   first argument has a reference count of 1.  Patch by Nikolaus Rath.

Objects/bytearrayobject.c

@@ -813,21 +813,9 @@ bytearray_init(PyByteArrayObject *self, PyObject *args, PyObject *kwds)
     }
     else {
         if (count > 0) {
-            void *sval;
-            Py_ssize_t alloc;
-
-            assert (Py_SIZE(self) == 0);
-
-            alloc = count + 1;
-            sval = PyObject_Calloc(1, alloc);
-            if (sval == NULL)
+            if (PyByteArray_Resize((PyObject *)self, count))
                 return -1;
-
-            PyObject_Free(self->ob_bytes);
-
-            self->ob_bytes = self->ob_start = sval;
-            Py_SIZE(self) = count;
-            self->ob_alloc = alloc;
+            memset(PyByteArray_AS_STRING(self), 0, count);
         }
         return 0;
     }