pythongh-126980: Fix bytearray.__buffer__ crash on PyBUF_{READ,WRITE} (python#126981)

Co-authored-by: Victor Stinner <vstinner@python.org>

Author: 2 people

Lib/test/test_buffer.py

@@ -4439,6 +4439,14 @@ def test_issue_7385(self):
  x = ndarray([1,2,3], shape=[3], flags=ND_GETBUF_FAIL)
  self.assertRaises(BufferError, memoryview, x)
 
+ def test_bytearray_release_buffer_read_flag(self):
+ # See https://github.com/python/cpython/issues/126980
+ obj = bytearray(b'abc')
+ with self.assertRaises(SystemError):
+ obj.__buffer__(inspect.BufferFlags.READ)
+ with self.assertRaises(SystemError):
+ obj.__buffer__(inspect.BufferFlags.WRITE)
+
  @support.cpython_only
  def test_pybuffer_size_from_format(self):
  # basic tests

Misc/NEWS.d/next/Core_and_Builtins/2024-11-18-23-18-17.gh-issue-126980.r8QHdi.rst

@@ -0,0 +1,3 @@
+Fix :meth:`~object.__buffer__` of :class:`bytearray` crashing when
+:attr:`~inspect.BufferFlags.READ` or :attr:`~inspect.BufferFlags.WRITE` are
+passed as flags.

Objects/bytearrayobject.c

@@ -52,8 +52,9 @@ bytearray_getbuffer(PyObject *self, Py_buffer *view, int flags)
  }
 
  void *ptr = (void *) PyByteArray_AS_STRING(obj);
- /* cannot fail if view != NULL and readonly == 0 */
- (void)PyBuffer_FillInfo(view, (PyObject*)obj, ptr, Py_SIZE(obj), 0, flags);
+ if (PyBuffer_FillInfo(view, (PyObject*)obj, ptr, Py_SIZE(obj), 0, flags) < 0) {
+ return -1;
+ }
  obj->ob_exports++;
  return 0;
 }