[issue44222] Improving _removeHandlerRef for a very long _handlerList
Change by Yonatan Goldschmidt : -- resolution: -> fixed stage: patch review -> resolved status: open -> closed ___ Python tracker <https://bugs.python.org/issue44222> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue44222] Improving _removeHandlerRef for a very long _handlerList
Yonatan Goldschmidt added the comment: That system has many (>10k) objects of a certain type. Each of them has a separate Logger object + Handlers. That was done, among other reasons, to allow for easy consuming of the logs relating to a particular object in a file-based manner. I agree that it's not common at all (other Python projects I've worked on don't exhibit this behavior) but since this change is harmless I thought we might as well make it. -- ___ Python tracker <https://bugs.python.org/issue44222> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue44222] Improving _removeHandlerRef for a very long _handlerList
Change by Yonatan Goldschmidt : -- keywords: +patch pull_requests: +24918 stage: -> patch review pull_request: https://github.com/python/cpython/pull/26325 ___ Python tracker <https://bugs.python.org/issue44222> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue44222] Improving _removeHandlerRef for a very long _handlerList
New submission from Yonatan Goldschmidt : We have an application which creates 10,000s of logging.Logger & logging.Handler objects. I encountered a major slowdown during GCs which happen to collect dead Handler objects, calling logging._removeHandlerRef() along the way. That function looks like: def _removeHandlerRef(wr): acquire, release, handlers = _acquireLock, _releaseLock, _handlerList if acquire and release and handlers: acquire() try: if wr in handlers: handlers.remove(wr) finally: release() and is called by a weakref, attached to each Handler created in _addHandlerRef(). The slowdown occurs in the "in" operator, and the remove() call. These operations on very long lists are expensive. My suggestion is that, without modifying the observed behavior of this function, it can be changed to perform only one lookup in the list, by simply calling remove() and ignoring the ValueError if it gets raised. Attached is a small script which demonstrates the issue. It creates N1 Handler objects, then deletes the strong reference to the last N2 handler objects, and triggers a GC, measuring the time it takes. Additionally, we can measure its entire execution (since all remaining Handler objects are cleaned up on exit, and eventually _removeHandlerRef() is called for each, and it drastically slows down the interpreter shutdown). Running the demo with N1=30k and N2=2k: root@8aafe9d1308b:/# python -V Python 3.9.2 root@8aafe9d1308b:/# time python demo.py 3 2000 len(logging._handlerList)=30001 len(logging._handlerList)=28001 gc.collect() took 1.552838139992673s real0m12.626s user0m12.618s sys 0m0.008s then applying the improving patch... root@8aafe9d1308b:/# (cd /usr/local/lib/python3.9/ && patch -p2 < /patch ) patching file logging/__init__.py Hunk #1 succeeded at 826 (offset -19 lines). and trying again: root@8aafe9d1308b:/# time python demo.py 3 2000 len(logging._handlerList)=30001 len(logging._handlerList)=28001 gc.collect() took 0.8691686679958366s real0m7.134s user0m7.130s sys 0m0.004s root@8aafe9d1308b:/# Almost a 2x speedup. I also tried removing the acquire/release locks (now that the remove operation is atomic...). I'm not sure it maintains the semantics, and it didn't make too much of a positive effect on the run-time anyway, so I didn't continue looking into it. -- components: Library (Lib) files: demo.py messages: 394229 nosy: Yonatan Goldschmidt priority: normal severity: normal status: open title: Improving _removeHandlerRef for a very long _handlerList type: performance versions: Python 3.11 Added file: https://bugs.python.org/file50060/demo.py ___ Python tracker <https://bugs.python.org/issue44222> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue31356] Add context manager to temporarily disable GC
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue31356> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue36656] Add race-free os.link and os.symlink wrapper / helper
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue36656> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue29657] os.symlink: FileExistsError shows wrong message
Yonatan Goldschmidt added the comment: Just reached this issue independently (spent a few minutes debugging an error message like "FileExistsError: [Errno 17] File exists: 'a' -> 'b'", where 'a' didn't exist...) I agree with Rich on this - for me, the source of confusion was that the way Python uses the arrow notation is just swapped from how ls(1) uses it. Stage is "patch review" but I couldn't find any PR for it; if we're good with Larry's solution then I'm happy to post a PR implementing it. ------ nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue29657> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue41545] gc API requiring matching number of gc.disable - gc.enable calls
Yonatan Goldschmidt added the comment: Dennis, you're right. I guess I missed it when I previously searched for matching issues. https://bugs.python.org/issue31356 indeed solves my problem. Closing this as a duplicate. -- resolution: -> duplicate stage: -> resolved status: open -> closed ___ Python tracker <https://bugs.python.org/issue41545> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue42287] Use Py_NewRef & Py_XNewRef where applicable
Yonatan Goldschmidt added the comment: > I don't see how Py_NewRef() or Py_XNewRef() is less error prone. In my > experience, any change is more likely to introduce new bugs than leaving the > code unchanged. Agree that inserting changes opens a door to introducing bugs. However, the "end state" of having Py_NewRef() is desired, I think. It is more concise. It is less error prone because where you use it, you literally can't miss the "increment refcount" part when stealing a reference from another source. Py_INCREF has to come before/after stealing a ref, leaving room for error, IMHO. > In general, we don't accept changes which are only coding style changes. Didn't know that. Well if that's the case, then obviously there is no reason to work specifically on this conversion. -- ___ Python tracker <https://bugs.python.org/issue42287> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue42287] Use Py_NewRef & Py_XNewRef where applicable
New submission from Yonatan Goldschmidt : Following https://bugs.python.org/issue42262, I think it'd be nice to convert existing C code to use the more concise Py_NewRef() and Py_XNewRef() where possible. Increases readability and less bug prone. Opening this new issue to track the conversion. -- components: Interpreter Core messages: 380531 nosy: Yonatan Goldschmidt, vstinner priority: normal severity: normal status: open title: Use Py_NewRef & Py_XNewRef where applicable type: enhancement versions: Python 3.10 ___ Python tracker <https://bugs.python.org/issue42287> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue42266] LOAD_ATTR cache does not fully replicate PyObject_GetAttr behavior
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue42266> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue42173] Drop Solaris support
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue42173> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue42143] Corruptions in func_dealloc() with partially-created function object
Change by Yonatan Goldschmidt : -- keywords: +patch pull_requests: +21871 stage: -> patch review pull_request: https://github.com/python/cpython/pull/22953 ___ Python tracker <https://bugs.python.org/issue42143> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue42143] Corruptions in func_dealloc() with partially-created function object
New submission from Yonatan Goldschmidt :
While reading funcobject.c, I noticed that PyFunction_NewWithQualName() may
exit early if it fails retrieving __name__ from the globals dict.
It will destroy the partially-created PyFunction object. However, this is done
before ever initializing ->func_qualname. Since the object is allocated with
PyObject_GC_New() (which does *not* provide zero-initialized memory), we are
using Py_CLEAR() on uninitialized memory.
I wrote a simple snippet to produce this bug, expecting to see a crash due to
the Py_DECREF() call on garbage memory:
from types import FunctionType
import random
class BadEq:
def __hash__(self):
print("hash called")
return hash("__name__")
def __eq__(self, other):
print("eq called")
raise Exception()
# run until we hit a 0x61616161.. pointer for
PyFunctionObject->func_qualname, and crash
while True:
s = int(random.random() * 1000) * "a"
try:
FunctionType(BadEq.__hash__.__code__, {BadEq(): 1})
except Exception:
pass
However, I got *another* crash immediately: func_dealloc() calls
_PyObject_GC_UNTRACK() which crashes if _PyObject_GC_TRACK() was not called
beforehand. When running with "--with-pydebug", you get this nice assert:
Objects/funcobject.c:595: _PyObject_GC_UNTRACK: Assertion "(((PyGC_Head
*)(op)-1)->_gc_next != 0)" failed: object not tracked by the garbage collector
I replaced "_PyObject_GC_UNTRACK(op);" in func_dealloc() with:
if (PyObject_GC_IsTracked(op)) {
_PyObject_GC_UNTRACK(op);
}
And ran my snippet again, this time it crashes after some loops with the error
I was expecting to receive
(here I print _py_tmp, the temporary variable inside Py_CLEAR()):
Program received signal SIGSEGV, Segmentation fault.
func_clear (op=op@entry=0x7f9c8a25faf0) at Objects/funcobject.c:587
587 Py_CLEAR(op->func_qualname);
(gdb) p _py_tmp
$1 = (PyObject *) 0x6161616161616161
This issue exists since https://github.com/python/cpython/pull/2, which
fixed tons of call sites to use PyDict_GetItemWithError(), I guess that this
specific flow was not tested.
As a fix, I think we should run the part that can result in errors *before*
creating the PyFunction, so we can no longer get an error while we have a
partial object. This fixes both of the problems I've described. Thus we can
move the dict lookup part to the top of
PyFunction_NewWithQualName().
I see no reason not to make such a change in the function's flow. If we'd
rather keep the flow as-is, we can make sure to initialize ->func_qualname to
NULL, and wrap _PyObject_GC_UNTRACK() with _PyObject_GC_IS_TRACKED() in
func_dealloc(). I like this solution less because it adds this unnecessary "if"
statement in func_dealloc().
I'll post a PR in GitHub soon.
--
components: Interpreter Core
messages: 379546
nosy: Yonatan Goldschmidt
priority: normal
severity: normal
status: open
title: Corruptions in func_dealloc() with partially-created function object
type: crash
versions: Python 3.10
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[issue42127] functools.cached_property possibly disables key-sharing instance dictionaries
New submission from Yonatan Goldschmidt : Key-sharing dictionaries, defined by https://www.python.org/dev/peps/pep-0412/, require that any resizing of the shared dictionary keys will happen before a second instance of the class is created. cached_property inserts its resolved result into the instance dict after it is called. This is likely to happen *after* a second instance has been created, and it is also likely to cause a resize of the dict, as demonstrated by this snippet: from functools import cached_property import sys def dict_size(o): return sys.getsizeof(o.__dict__) class X: def __init__(self): self.a = 1 self.b = 2 self.c = 3 self.d = 4 self.e = 5 @cached_property def f(self): return id(self) x1 = X() x2 = X() print(dict_size(x1)) print(dict_size(x2)) x1.f print(dict_size(x1)) print(dict_size(x2)) x3 = X() print(dict_size(x3)) Essentially it means that types using cached_property are less likely to enjoy the benefits of shared keys. It may also incur a certain performance hit, because a resize + unshare will happen every time. A simple way I've thought of to let cached_property play more nicely with shared keys, is to first create a single object of the class, and set the cached_property attribute to some value (so the key is added to the shared dict). In the snippet above, if you add "x0 = X(); x0.f = None" before creating x1 and x2, you'll see that the cached_property resolving does not unshare the dicts. But I wonder if there's a way to do so without requiring user code changes. -- components: Library (Lib) messages: 379439 nosy: Yonatan Goldschmidt priority: normal severity: normal status: open title: functools.cached_property possibly disables key-sharing instance dictionaries type: performance versions: Python 3.10 ___ Python tracker <https://bugs.python.org/issue42127> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue41545] gc API requiring matching number of gc.disable - gc.enable calls
Yonatan Goldschmidt added the comment: Hmm... I didn't think of overlapping lock periods. You are right, Dennis, a counter must be managed. -- ___ Python tracker <https://bugs.python.org/issue41545> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue41545] gc API requiring matching number of gc.disable - gc.enable calls
Yonatan Goldschmidt added the comment: > This is exactly the motivation for context managers, no? I attached no_gc.py, > which works when nested and should additionally be thread-safe. My solution was roughly the same (also a context manager, but a bit simplified because I didn't need threading support so I didn't bother with locking). > There is also gc.isenabled(), so couldn't you check that before disabling and > remember whether you needed to disable or not? Yes, but it must be protected like Dennis suggested, otherwise it can't be used in a race-free way, for example this snippet is susceptible to a thread switch between the `isenabled()` and `disable()` calls (so another thread could meanwhile disable GC, and we retain a stale `was_enabled` result) was_enabled = gc.isenabled() gc.disable() ... if was_enabled: gc.enable() My points in this issue are: 1. I think that such a safer API should be available in the standard library (I don't want to find myself repeating this across different projects). I think that wherever you find yourself using `gc.disable()` you should actually be using a safer API (that takes into account multithreading & previous invocations of `gc.disable()`) 2. A tiny change in `gc.enable()` (as I suggested in msg375376) can make it substantially easier for the Python side to protect itself, because it will be race-free without any locks. -- ___ Python tracker <https://bugs.python.org/issue41545> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue41545] gc API requiring matching number of gc.disable - gc.enable calls
Yonatan Goldschmidt added the comment:
> If this race condition is a bug in gc, then we should fix that.
> If it is a bug in your code, surely you should fix that rather than disable
> gc.
It's neither: it is something related to the combination of some 3rd party
libraries I'm using (if you're interested, I have described it here:
https://github.com/paramiko/paramiko/issues/1634).
> Either way, I don't think we should complicate the gc iterface by adding a
> second way to enable and disable the cyclic gc.
I see what you're saying. I wasn't thinking of of this idea as complicating it,
I had in mind existing interfaces which have these 2 sets of functions (for
example, Linux's local_irq_enable/disable and local_irq_save/restore).
Another approach, only modifying the existing API in a compatible way, will be
as follows:
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -1489,9 +1489,10 @@ static PyObject *
gc_disable_impl(PyObject *module)
/*[clinic end generated code: output=97d1030f7aa9d279
input=8c2e5a14e800d83b]*/
{
+int was_enabled = gcstate->enabled
GCState *gcstate = get_gc_state();
gcstate->enabled = 0;
-Py_RETURN_NONE;
+return was_enabled ? (Py_INCREF(Py_True), Py_True) :
(Py_INCREF(Py_False), Py_False);
}
Then I can write code this way:
foo():
disabled = gc.disable()
if disabled:
gc.enable()
It can be taken ahead to change `gc.enable()` to `gc.enable(disabled=True)` so
I can just call it as `gc.enable(disabled)`:
foo():
disabled = gc.disable()
gc.enable(disabled)
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[issue41545] gc API requiring matching number of gc.disable - gc.enable calls
New submission from Yonatan Goldschmidt : I have a construct in my code where I wrap a function's logic with `gc.disable()` to prevent GC from triggering some race condition. Today this construct got a bit more complicated, and another function had to use this "trick". Now there are 2 flows: foo(): gc.disable() gc.enable() bar() gc.disable() ... # bar calls foo, which also messes with the gc foo() gc.disable() ... gc.enable() ... gc.enable() ... I'd expected the GC to be truly enabled only on the second call to `enable()`, but apparently it's enabled on the first call :( Both `gc.enable()` and `gc.disable()` just write `1`/`0` to `gcstate->enabled`, respectively. For the meantime I wrote a simple wrapper class to do this counting (finally calling `enable()` only when necessary). Another option is for the code to check first "is GC enabled?" before disabling, and before enabling again, remember whether it really disabled it or not. But I think those manual workarounds are more error prone, and it's easier to forget to use it them in all sites (compared to using the "right" API from the standard module), so I was considering if we can add an API that encapsulate this counting: an enable-disable pair that makes sure GC is only enabled back when the number of "enable" calls matches the number of "disable" calls. -- components: Interpreter Core messages: 375355 nosy: Yonatan Goldschmidt priority: normal severity: normal status: open title: gc API requiring matching number of gc.disable - gc.enable calls type: enhancement versions: Python 3.10 ___ Python tracker <https://bugs.python.org/issue41545> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue10399] AST Optimization: inlining of function calls
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue10399> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue41427] howto/descriptor.rst unnecessarily mentions method.__class__
Change by Yonatan Goldschmidt : -- keywords: +patch pull_requests: +20810 stage: -> patch review pull_request: https://github.com/python/cpython/pull/21665 ___ Python tracker <https://bugs.python.org/issue41427> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue41427] howto/descriptor.rst unnecessarily mentions method.__class__
New submission from Yonatan Goldschmidt : In Doc/howto/descriptor.rst: # Internally, the bound method stores the underlying function, # the bound instance, and the class of the bound instance. >>> d.f.__func__ >>> d.f.__self__ <__main__.D object at 0x1012e1f98> >>> d.f.__class__ The bound method (PyMethodObject) does not store "the class of the bound instance" - it only stores the "function" and "self". d.f.__class__ is the class of the "method" type itself, not the class of d.f's instance (D from d = D()) I think this mention should be removed from the documentation? -- assignee: docs@python components: Documentation messages: 374526 nosy: Yonatan Goldschmidt, docs@python priority: normal severity: normal status: open title: howto/descriptor.rst unnecessarily mentions method.__class__ type: enhancement versions: Python 3.10 ___ Python tracker <https://bugs.python.org/issue41427> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35823] Use vfork() in subprocess on Linux
Yonatan Goldschmidt added the comment: With issue35537 merged, do we have any intention to get on with this? From what I can tell, it provides roughly the same performance benefit - but works also with close_fds=True, which is the default of Popen, so IMO it's a worthy addition. I tested a rebase on current master, test_subprocess passes on my Linux box and there are no more -Wclobbered warnings after Alexey's latest change of the do_fork_exec() helper. -- ___ Python tracker <https://bugs.python.org/issue35823> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue35823] Use vfork() in subprocess on Linux
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue35823> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue40222] "Zero cost" exception handling
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue40222> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue4264] Patch: optimize code to use LIST_APPEND instead of calling list.append
Change by Yonatan Goldschmidt : -- nosy: +Yonatan Goldschmidt ___ Python tracker <https://bugs.python.org/issue4264> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue39382] abstract_issubclass() doesn't take bases tuple item ref
Change by Yonatan Goldschmidt : -- pull_requests: +17906 stage: -> patch review pull_request: https://github.com/python/cpython/pull/18530 ___ Python tracker <https://bugs.python.org/issue39382> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue39382] abstract_issubclass() doesn't take bases tuple item ref
New submission from Yonatan Goldschmidt :
I encountered a crash using rpyc. Since rpyc is pure-Python, I guessed the
problem is with Python itself.
Originally tested on v3.7, the rest of this issue is based on v3.9.0a2
(compiling on an Ubuntu 18.04 docker).
I narrowed down the rpyc-based snippet to this:
# server side
class X: pass
x_instance = X()
from rpyc.core import SlaveService
from rpyc.utils.classic import DEFAULT_SERVER_PORT
from rpyc.utils.server import ThreadedServer
t = ThreadedServer(SlaveService, port=DEFAULT_SERVER_PORT, reuse_addr=True)
t.start()
# client side
import rpyc
conn = rpyc.classic.connect("localhost")
x = conn.modules.__main__.x_instance
y = x.__class__
issubclass(y, int)
Client side gets a SIGSEGV in `_PyObject_LookupAttr`, dereferencing an invalid
`tp` pointer read from a posioned `v` object.
After some reference count debugging, I found that for the rpyc `y` object (in
the client code), accessing `__bases__` returns a tuple with refcount=1, and it
has a single item whose refcount is 1 as well.
abstract_issubclass() calls abstract_get_bases() to get this refcount=1 tuple,
and in the fastpath for single inheritance (tuple size = 1) it loads the single
item from the tuple (`derived = PyTuple_GET_ITEM(bases, 0)`) and then
decrements the refcount on the tuple, effectively deallocating the tuple and
the `derived` object (whose only reference was from the tuple).
I tried to mimic the Python magic rpyc does to get the same crash without rpyc,
and reached the following snippet (which doesn't exhibit the problem):
class Meta(type):
def __getattribute__(self, attr):
if attr == "__bases__":
class Base: pass
return (Base, )
return type.__getattribute__(self, attr)
class X(metaclass=Meta):
pass
issubclass(X().__class__, int)
In this case, the refcount is decremented from 4 to 3 as abstract_issubclass()
gets rid of the tuple (instead of from 1 to 0 as happens in the rpyc case). I
don't know how rpyc does it.
Attached is a patch that solves the problem (takes a ref of the tuple item
before releasing the ref of the tuple itself).
I'm not sure this change is worth the cost because, well, I don't fully
understand the severity of it since I couldn't reproduce it without using rpyc.
I assume dynamically-created, unreferenced `__bases__` tuples as I have here
are not so common.
Anyway, if you do decide it's worth it, I'd be happy to improve the patch (it's
quite messy the way this function is structured) and post it to GitHub :)
Yonatan
--
components: Interpreter Core
files: abstract_issubclass_refcount_fix.diff
keywords: patch
messages: 360247
nosy: Yonatan Goldschmidt
priority: normal
severity: normal
status: open
title: abstract_issubclass() doesn't take bases tuple item ref
type: crash
versions: Python 3.9
Added file:
https://bugs.python.org/file48851/abstract_issubclass_refcount_fix.diff
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