Skip to content

gh-123471: Make concurrent iteration over itertools.pairwise thread-safe #144489

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
eendebakpt wants to merge 6 commits into
base: main
Choose a base branch
from
+26 −6
Open

gh-123471: Make concurrent iteration over itertools.pairwise thread-safe #144489

Changes from 1 commit
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
8810175
add test for pairwise
eendebakpt Feb 4, 2026
11e727d
Make itertools.pairwise safe in the FT build
eendebakpt Feb 4, 2026
a91f13c
add comment for incref rationale
eendebakpt Feb 4, 2026
931b2f9
add comment for incref rationale
eendebakpt Feb 4, 2026
a030f5a
📜🤖 Added by blurb_it.
blurb-it[bot] Feb 4, 2026
9c87957
Merge branch 'pairwise_ft_v3' of github.com:eendebakpt/cpython into p…
eendebakpt Feb 4, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
Make itertools.pairwise safe in the FT build
  • Loading branch information
@eendebakpt
eendebakpt committed Feb 4, 2026
commit 11e727dd28aa9f27b6d9e0888152aef3052c41f4
20 changes: 16 additions & 4 deletions Modules/itertoolsmodule.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -343,7 +343,7 @@ pairwise_traverse(PyObject *op, visitproc visit, void *arg)
}

static PyObject *
pairwise_next(PyObject *op)
pairwise_next_lock_held(PyObject *op)
{
pairwiseobject *po = pairwiseobject_CAST(op);
PyObject *it = po->it;
Expand Down Expand Up @@ -380,7 +380,7 @@ pairwise_next(PyObject *op)
Py_INCREF(result);
PyObject *last_old = PyTuple_GET_ITEM(result, 0);
PyObject *last_new = PyTuple_GET_ITEM(result, 1);
PyTuple_SET_ITEM(result, 0, Py_NewRef(old));
PyTuple_SET_ITEM(result, 0, old);
PyTuple_SET_ITEM(result, 1, Py_NewRef(new));
Py_DECREF(last_old);
Py_DECREF(last_new);
Expand All @@ -391,13 +391,25 @@ pairwise_next(PyObject *op)
else {
result = PyTuple_New(2);
if (result != NULL) {
PyTuple_SET_ITEM(result, 0, Py_NewRef(old));
PyTuple_SET_ITEM(result, 0, old);
PyTuple_SET_ITEM(result, 1, Py_NewRef(new));
}
else {
Py_DECREF(old);
}
}

Py_XSETREF(po->old, new);
Py_DECREF(old);
return result;
}

static PyObject *
pairwise_next(PyObject *op)
{
PyObject *result;
Py_BEGIN_CRITICAL_SECTION(op);
result = pairwise_next_lock_held(op);
Py_END_CRITICAL_SECTION()
return result;
}

Expand Down