diff options
| -rw-r--r-- | Lib/test/test_bytes.py | 10 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2021-01-13-14-06-01.bpo-42924._WS1Ok.rst | 1 | ||||
| -rw-r--r-- | Objects/bytearrayobject.c | 6 |
3 files changed, 15 insertions, 2 deletions
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py index 05568f2..227e6d7 100644 --- a/Lib/test/test_bytes.py +++ b/Lib/test/test_bytes.py @@ -1664,6 +1664,16 @@ class ByteArrayTest(BaseBytesTest, unittest.TestCase): # Shouldn't raise an error self.assertEqual(list(it), []) + def test_repeat_after_setslice(self): + # bpo-42924: * used to copy from the wrong memory location + b = bytearray(b'abc') + b[:2] = b'x' + b1 = b * 1 + b3 = b * 3 + self.assertEqual(b1, b'xc') + self.assertEqual(b1, b) + self.assertEqual(b3, b'xcxcxc') + class AssortedBytesTest(unittest.TestCase): # diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-01-13-14-06-01.bpo-42924._WS1Ok.rst b/Misc/NEWS.d/next/Core and Builtins/2021-01-13-14-06-01.bpo-42924._WS1Ok.rst new file mode 100644 index 0000000..33fbb52 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2021-01-13-14-06-01.bpo-42924._WS1Ok.rst @@ -0,0 +1 @@ +Fix ``bytearray`` repetition incorrectly copying data from the start of the buffer, even if the data is offset within the buffer (e.g. after reassigning a slice at the start of the ``bytearray`` to a shorter byte string). diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c index 97d7796..a1aa880 100644 --- a/Objects/bytearrayobject.c +++ b/Objects/bytearrayobject.c @@ -329,6 +329,7 @@ bytearray_repeat(PyByteArrayObject *self, Py_ssize_t count) PyByteArrayObject *result; Py_ssize_t mysize; Py_ssize_t size; + const char *buf; if (count < 0) count = 0; @@ -337,13 +338,14 @@ bytearray_repeat(PyByteArrayObject *self, Py_ssize_t count) return PyErr_NoMemory(); size = mysize * count; result = (PyByteArrayObject *)PyByteArray_FromStringAndSize(NULL, size); + buf = PyByteArray_AS_STRING(self); if (result != NULL && size != 0) { if (mysize == 1) - memset(result->ob_bytes, self->ob_bytes[0], size); + memset(result->ob_bytes, buf[0], size); else { Py_ssize_t i; for (i = 0; i < count; i++) - memcpy(result->ob_bytes + i*mysize, self->ob_bytes, mysize); + memcpy(result->ob_bytes + i*mysize, buf, mysize); } } return (PyObject *)result; |