bpo-42266: Handle monkey-patching descriptors in LOAD_ATTR cache (GH-23157)

This commit is contained in:
Pablo Galindo 2020-11-05 09:23:15 +00:00 committed by GitHub
parent 178695b7ae
commit 80449f243b
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 28 additions and 7 deletions

23
Lib/test/test_opcache.py Normal file
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@ -0,0 +1,23 @@
import unittest
class TestLoadAttrCache(unittest.TestCase):
def test_descriptor_added_after_optimization(self):
class Descriptor:
pass
class C:
def __init__(self):
self.x = 1
x = Descriptor()
def f(o):
return o.x
o = C()
for i in range(1025):
assert f(o) == 1
Descriptor.__get__ = lambda self, instance, value: 2
Descriptor.__set__ = lambda *args: None
self.assertEqual(f(o), 2)

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@ -0,0 +1,3 @@
Fixed a bug with the LOAD_ATTR opcode cache that was not respecting
monkey-patching a class-level attribute to make it a descriptor. Patch by
Pablo Galindo.

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@ -1196,6 +1196,7 @@
<Compile Include="test\test_nntplib.py" />
<Compile Include="test\test_ntpath.py" />
<Compile Include="test\test_numeric_tower.py" />
<Compile Include="test\test_opcache.py" />
<Compile Include="test\test_opcodes.py" />
<Compile Include="test\test_openpty.py" />
<Compile Include="test\test_operator.py" />

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@ -3179,7 +3179,6 @@ main_loop:
if (co_opcache != NULL && /* co_opcache can be NULL after a DEOPT() call. */
type->tp_getattro == PyObject_GenericGetAttr)
{
PyObject *descr;
Py_ssize_t ret;
if (type->tp_dictoffset > 0) {
@ -3190,12 +3189,7 @@ main_loop:
goto error;
}
}
descr = _PyType_Lookup(type, name);
if (descr == NULL ||
Py_TYPE(descr)->tp_descr_get == NULL ||
!PyDescr_IsData(descr))
{
if (_PyType_Lookup(type, name) == NULL) {
dictptr = (PyObject **) ((char *)owner + type->tp_dictoffset);
dict = *dictptr;