Maybe such issue can be detected if Raymond uses the bug tracker for code review? I remember many cases where Serhiy and Raymond collaborated successfully and wrote better code thanks to the code review.
Victor 2015-07-07 9:42 GMT+02:00 Serhiy Storchaka <storch...@gmail.com>: > On 07.07.15 05:03, raymond.hettinger wrote: >> >> https://hg.python.org/cpython/rev/c9782a9ac031 >> changeset: 96865:c9782a9ac031 >> user: Raymond Hettinger <pyt...@rcn.com> >> date: Mon Jul 06 19:03:01 2015 -0700 >> summary: >> Tighten-up code in the set iterator to use an entry pointer rather than >> indexing. >> >> files: >> Objects/setobject.c | 35 ++++++++++++-------------------- >> 1 files changed, 13 insertions(+), 22 deletions(-) >> >> >> diff --git a/Objects/setobject.c b/Objects/setobject.c >> --- a/Objects/setobject.c >> +++ b/Objects/setobject.c >> @@ -766,8 +766,8 @@ >> PyObject_HEAD >> PySetObject *si_set; /* Set to NULL when iterator is exhausted */ >> Py_ssize_t si_used; >> - Py_ssize_t si_pos; >> Py_ssize_t len; >> + setentry *entry; >> } setiterobject; >> >> static void >> @@ -845,8 +845,6 @@ >> >> static PyObject *setiter_iternext(setiterobject *si) >> { >> - PyObject *key; >> - Py_ssize_t i, mask; >> setentry *entry; >> PySetObject *so = si->si_set; >> >> @@ -860,25 +858,18 @@ >> si->si_used = -1; /* Make this state sticky */ >> return NULL; >> } >> - >> - i = si->si_pos; >> - assert(i>=0); >> - entry = so->table; >> - mask = so->mask; >> - while (i <= mask && (entry[i].key == NULL || entry[i].key == dummy)) >> - i++; >> - si->si_pos = i+1; >> - if (i > mask) >> - goto fail; >> + if (si->len <= 0) { >> + Py_DECREF(so); >> + si->si_set = NULL; >> + return NULL; >> + } >> + entry = si->entry; >> + while (entry->key == NULL || entry->key == dummy) >> + entry++; >> si->len--; >> - key = entry[i].key; >> - Py_INCREF(key); >> - return key; >> - >> -fail: >> - Py_DECREF(so); >> - si->si_set = NULL; >> - return NULL; >> + si->entry = entry + 1; >> + Py_INCREF(entry->key); >> + return entry->key; >> } >> >> PyTypeObject PySetIter_Type = { >> @@ -923,8 +914,8 @@ >> Py_INCREF(so); >> si->si_set = so; >> si->si_used = so->used; >> - si->si_pos = 0; >> si->len = so->used; >> + si->entry = so->table; >> _PyObject_GC_TRACK(si); >> return (PyObject *)si; >> } > > > What if so->table was reallocated during the iteration, but so->used is left > the same? This change looks unsafe to me. > > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > https://mail.python.org/mailman/options/python-dev/victor.stinner%40gmail.com _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
