bpo-32999: Fix ABC.subclasscheck crash #6002

methane · 2018-03-06T11:31:46Z

C implementation of ABC.__subclasscheck__(cls, subclass) crashed when subclass is not type object.

This commit makes C implementation more similar to Python implementation.

https://bugs.python.org/issue32999

zhangyangyu · 2018-03-06T11:44:38Z

Modules/_abc.c

+     *     return True
+     */
+    _Py_IDENTIFIER(__mro__);
+    if (_PyObject_LookupAttrId(subclass, &PyId___mro__, &mro) < 0) {


mro is leaked.

As well as impl.

ilevkivskyi

Thanks! Just two minor comments

ilevkivskyi · 2018-03-06T11:49:51Z

Lib/test/test_abc.py

@@ -392,6 +392,13 @@ class MyInt(int):
            self.assertIsInstance(42, A)
            self.assertIsInstance(42, (A,))

+        def test_issubclass(self):


I would rather make the test name more specific, or add few more corner cases here.

ilevkivskyi · 2018-03-06T11:49:51Z

Modules/_abc.c

+     */
+    _Py_IDENTIFIER(__mro__);
+    if (_PyObject_LookupAttrId(subclass, &PyId___mro__, &mro) < 0) {
+        return NULL;


Maybe this should be goto end; or similar? (for clean-up)

zhangyangyu · 2018-03-06T12:41:53Z

Modules/_abc.c

@@ -690,6 +699,7 @@ _abc__abc_subclasscheck_impl(PyObject *module, PyObject *self,
    result = Py_False;

 end:
+    Py_XDECREF(mro);
    Py_XDECREF(impl);


Looks to me impl can't be NULL here.

izbyshev · 2018-03-06T13:13:29Z

Lib/test/test_abc.py

+                __mro__ = 42  # __mro__ is not tuple
+
+            with self.assertRaises(TypeError):
+                self.assertTrue(issubclass(C(), A))


self.assertTrue is not needed.

ilevkivskyi

LGTM now.

zhangyangyu · 2018-03-06T14:43:51Z

Modules/_abc.c

-            if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {
+        for (pos = 0; pos < PyTuple_GET_SIZE(mro); pos++) {
+            PyObject *mro_item = PyTuple_GET_ITEM(mro, pos);
+            if (mro_item == NULL) {


Is this check needed? If it is a must, we need to set an exception in this branch, otherwise we will return NULL while no exception set.

1st1 · 2018-03-06T16:32:15Z

Modules/_abc.c

@@ -258,6 +252,7 @@ _abc__get_dump(PyObject *module, PyObject *self)
 static int
 compute_abstract_methods(PyObject *self)
 {
+    _Py_IDENTIFIER(__abstractmethods__);


Why don't we define these identifiers at the top level?

I prefer local variable when it's used only in one function.
If you prefer top level, I'll revert unnecessary changes.

I usually move them to the top level as it's hard to track if a variable like this is used in one or in many functions. Really up to you though, I'm OK about this change either way.

This reverts commit e15fc35.

zhangyangyu

LGTM. +1 about the unittest name could be more specific, but it's just a preference.

methane · 2018-03-07T05:35:58Z

I'm bad at English, including vocabulary. Would you propose better name, instead of just saying "specific"?

zhangyangyu · 2018-03-07T05:44:13Z

I mean something like test_issubclass_bad_arguments since the test only tests for exception cases.

miss-islington · 2018-03-07T07:27:03Z

Thanks @methane for the PR 🌮🎉.. I'm working now to backport this PR to: 3.7.
🐍🍒⛏🤖

(cherry picked from commit fc7df0e) Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

bedevere-bot · 2018-03-07T07:28:12Z

GH-6014 is a backport of this pull request to the 3.7 branch.

(cherry picked from commit fc7df0e) Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

bpo-33018 (pythonGH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

bpo-33018 (pythonGH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case. (cherry picked from commit f757b72) Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

bpo-33018 (GH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

bpo-33018 (GH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case. (cherry picked from commit f757b72) Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

bpo-33018 (pythonGH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

methane added 4 commits Mar 6, 2018

Move identifiers to function local

e15fc35

add test

868fa3a

fix the bug

97ec4e7

Add NEWS

59998e7

the-knights-who-say-ni added the CLA signed label Mar 6, 2018

bedevere-bot added the awaiting merge label Mar 6, 2018

methane requested review from 1st1 and ilevkivskyi Mar 6, 2018

methane added type-bug An unexpected behavior, bug, or error needs backport to 3.7 labels Mar 6, 2018

zhangyangyu reviewed Mar 6, 2018

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ilevkivskyi reviewed Mar 6, 2018

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Fix leak

b901e1e

zhangyangyu reviewed Mar 6, 2018

View changes

methane added 2 commits Mar 6, 2018

More corner cases

c06fcae

impl must not be NULL

7767ef7

izbyshev reviewed Mar 6, 2018

View changes

oops

e2aa5ca

ilevkivskyi approved these changes Mar 6, 2018

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zhangyangyu reviewed Mar 6, 2018

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Remove redundant NULL check

23f555f

1st1 reviewed Mar 6, 2018

View changes

methane added 2 commits Mar 6, 2018

Revert "Move identifiers to function local"

8bcb74c

This reverts commit e15fc35.

Move __mro__ identifier to top of the file

697abd2

zhangyangyu approved these changes Mar 7, 2018

View changes

rename test func

fa4af5f

methane merged commit fc7df0e into python:master Mar 7, 2018

bedevere-bot removed the awaiting merge label Mar 7, 2018

methane deleted the fix-abc-issubclass-bpo32999 branch Mar 7, 2018

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Mar 7, 2018

bpo-32999: Fix ABC.__subclasscheck__ crash (pythonGH-6002)

96ef3c1

(cherry picked from commit fc7df0e) Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

bedevere-bot removed the needs backport to 3.7 label Mar 7, 2018

miss-islington added a commit that referenced this pull request Mar 7, 2018

bpo-32999: Fix ABC.__subclasscheck__ crash (GH-6002)

d824b4e

(cherry picked from commit fc7df0e) Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

methane added a commit to methane/cpython that referenced this pull request Mar 22, 2018

bpo-32999: Revert pythonGH-6002 (fc7df0e)

cd7583e

bpo-33018 (pythonGH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

methane added a commit that referenced this pull request Mar 22, 2018

bpo-32999: Revert GH-6002 (fc7df0e) (GH-6189)

f757b72

bpo-33018 (GH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

jo2y pushed a commit to jo2y/cpython that referenced this pull request Mar 23, 2018

bpo-32999: Fix ABC.__subclasscheck__ crash (pythonGH-6002)

79536ea

jo2y pushed a commit to jo2y/cpython that referenced this pull request Mar 23, 2018

bpo-32999: Revert pythonGH-6002 (fc7df0e) (pythonGH-6189)

fc8d6e5

bpo-33018 (pythonGH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

yahya-abou-imran pushed a commit to yahya-abou-imran/cpython that referenced this pull request Nov 2, 2018

bpo-32999: Fix ABC.__subclasscheck__ crash (pythonGH-6002)

13538c2

yahya-abou-imran pushed a commit to yahya-abou-imran/cpython that referenced this pull request Nov 2, 2018

bpo-32999: Revert pythonGH-6002 (fc7df0e) (pythonGH-6189)

3ab9fed

bpo-33018 (pythonGH-5944) fixed bpo-32999 too. So fc7df0e is not required anymore. Revert it except test case.

bpo-32999: Fix ABC.subclasscheck crash #6002

bpo-32999: Fix ABC.subclasscheck crash #6002

methane commented Mar 6, 2018 •

edited by bedevere-bot

zhangyangyu Mar 6, 2018

izbyshev Mar 6, 2018

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ilevkivskyi Mar 6, 2018

1st1 Mar 6, 2018

ilevkivskyi Mar 6, 2018

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zhangyangyu Mar 6, 2018 •

edited

1st1 Mar 6, 2018

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methane commented Mar 7, 2018

zhangyangyu commented Mar 7, 2018

miss-islington commented Mar 7, 2018

bedevere-bot commented Mar 7, 2018

bpo-32999: Fix ABC.__subclasscheck__ crash #6002

bpo-32999: Fix ABC.__subclasscheck__ crash #6002

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methane commented Mar 6, 2018 • edited by bedevere-bot

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bedevere-bot commented Mar 7, 2018

bpo-32999: Fix ABC.subclasscheck crash #6002

bpo-32999: Fix ABC.subclasscheck crash #6002

methane commented Mar 6, 2018 •

edited by bedevere-bot

zhangyangyu Mar 6, 2018 •

edited