gh-67565: remove redundant C-contiguity checks

Lib/test/test_binascii.py

@@ -474,6 +474,12 @@ def test_base64_roundtrip(self, binary, newline):
  restored = binascii.a2b_base64(self.type2test(converted))
  self.assertConversion(binary, converted, restored, newline=newline)
 
+ def test_c_contiguity(self):
+ m = memoryview(bytearray(b'noncontig'))
+ noncontig_writable = m[::-2]
+ with self.assertRaises(BufferError):
+ binascii.b2a_hex(noncontig_writable)
+
 
 class ArrayBinASCIITest(BinASCIITest):
  def type2test(self, s):

Lib/test/test_capi/test_getargs.py

@@ -151,6 +151,8 @@ class TupleSubclass(tuple):
 class DictSubclass(dict):
  pass
 
+m = memoryview(bytearray(b'noncontig'))
+NONCONTIG_WRITABLE = m[::-2]
 
 class Unsigned_TestCase(unittest.TestCase):
  def test_b(self):
@@ -835,6 +837,7 @@ def test_y_star(self):
  self.assertEqual(getargs_y_star(bytearray(b'bytearray')), b'bytearray')
  self.assertEqual(getargs_y_star(memoryview(b'memoryview')), b'memoryview')
  self.assertRaises(TypeError, getargs_y_star, None)
+ self.assertRaises(BufferError, getargs_y_star, NONCONTIG_WRITABLE)
 
  def test_y_hash(self):
  from _testcapi import getargs_y_hash
@@ -844,6 +847,8 @@ def test_y_hash(self):
  self.assertRaises(TypeError, getargs_y_hash, bytearray(b'bytearray'))
  self.assertRaises(TypeError, getargs_y_hash, memoryview(b'memoryview'))
  self.assertRaises(TypeError, getargs_y_hash, None)
+ # TypeError: must be read-only bytes-like object, not memoryview
+ self.assertRaises(TypeError, getargs_y_hash, NONCONTIG_WRITABLE)
 
  def test_w_star(self):
  # getargs_w_star() modifies first and last byte
@@ -859,6 +864,7 @@ def test_w_star(self):
  self.assertEqual(getargs_w_star(memoryview(buf)), b'[emoryvie]')
  self.assertEqual(buf, bytearray(b'[emoryvie]'))
  self.assertRaises(TypeError, getargs_w_star, None)
+ self.assertRaises(TypeError, getargs_w_star, NONCONTIG_WRITABLE)
 
 
 class String_TestCase(unittest.TestCase):
@@ -891,6 +897,7 @@ def test_s_star(self):
  self.assertEqual(getargs_s_star(bytearray(b'bytearray')), b'bytearray')
  self.assertEqual(getargs_s_star(memoryview(b'memoryview')), b'memoryview')
  self.assertRaises(TypeError, getargs_s_star, None)
+ self.assertRaises(BufferError, getargs_s_star, NONCONTIG_WRITABLE)
 
  def test_s_hash(self):
  from _testcapi import getargs_s_hash
@@ -900,6 +907,8 @@ def test_s_hash(self):
  self.assertRaises(TypeError, getargs_s_hash, bytearray(b'bytearray'))
  self.assertRaises(TypeError, getargs_s_hash, memoryview(b'memoryview'))
  self.assertRaises(TypeError, getargs_s_hash, None)
+ # TypeError: must be read-only bytes-like object, not memoryview
+ self.assertRaises(TypeError, getargs_s_hash, NONCONTIG_WRITABLE)
 
  def test_z(self):
  from _testcapi import getargs_z
@@ -918,6 +927,7 @@ def test_z_star(self):
  self.assertEqual(getargs_z_star(bytearray(b'bytearray')), b'bytearray')
  self.assertEqual(getargs_z_star(memoryview(b'memoryview')), b'memoryview')
  self.assertIsNone(getargs_z_star(None))
+ self.assertRaises(BufferError, getargs_z_star, NONCONTIG_WRITABLE)
 
  def test_z_hash(self):
  from _testcapi import getargs_z_hash
@@ -927,6 +937,8 @@ def test_z_hash(self):
  self.assertRaises(TypeError, getargs_z_hash, bytearray(b'bytearray'))
  self.assertRaises(TypeError, getargs_z_hash, memoryview(b'memoryview'))
  self.assertIsNone(getargs_z_hash(None))
+ # TypeError: must be read-only bytes-like object, not memoryview
+ self.assertRaises(TypeError, getargs_z_hash, NONCONTIG_WRITABLE)
 
  def test_es(self):
  from _testcapi import getargs_es

Lib/test/test_ssl.py

@@ -1739,6 +1739,10 @@ def test_buffer_types(self):
  self.assertEqual(bio.read(), b'bar')
  bio.write(memoryview(b'baz'))
  self.assertEqual(bio.read(), b'baz')
+ m = memoryview(bytearray(b'noncontig'))
+ noncontig_writable = m[::-2]
+ with self.assertRaises(BufferError):
+ bio.write(memoryview(noncontig_writable))
 
  def test_error_types(self):
  bio = ssl.MemoryBIO()

Misc/NEWS.d/next/C API/2023-06-08-21-12-44.gh-issue-67565.UkK3x-.rst

@@ -0,0 +1 @@
+Remove redundant C-contiguity check in :file:`getargs.c`, :mod:`binascii`, :mod:`ssl` and Argument Clinic. Patched by Stefan Krah and Furkan Onder

Modules/_ssl.c

@@ -4133,7 +4133,8 @@ _ssl__SSLContext_load_verify_locations_impl(PySSLContext *self,
  if (PyObject_GetBuffer(cadata, &buf, PyBUF_SIMPLE)) {
  goto error;
  }
- if (!PyBuffer_IsContiguous(&buf, 'C') || buf.ndim > 1) {
+ assert(PyBuffer_IsContiguous(&buf, 'C'));
+ if (buf.ndim > 1) {
  PyBuffer_Release(&buf);
  PyErr_SetString(PyExc_TypeError,
  "cadata should be a contiguous buffer with "

Modules/binascii.c

@@ -185,13 +185,7 @@ ascii_buffer_converter(PyObject *arg, Py_buffer *buf)
  "not '%.100s'", Py_TYPE(arg)->tp_name);
  return 0;
  }
- if (!PyBuffer_IsContiguous(buf, 'C')) {
- PyErr_Format(PyExc_TypeError,
- "argument should be a contiguous buffer, "
- "not '%.100s'", Py_TYPE(arg)->tp_name);
- PyBuffer_Release(buf);
- return 0;
- }
+ assert(PyBuffer_IsContiguous(buf, 'C'));
  return Py_CLEANUP_SUPPORTED;
 }