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-rw-r--r--Lib/test/support/__init__.py27
-rw-r--r--Lib/test/test_iter.py2
-rw-r--r--Misc/NEWS.d/next/Core and Builtins/2024-02-14-23-50-55.gh-issue-112087.H_4W_v.rst2
-rw-r--r--Objects/listobject.c102
-rw-r--r--Python/bytecodes.c8
-rw-r--r--Python/executor_cases.c.h3
-rw-r--r--Python/generated_cases.c.h5
7 files changed, 80 insertions, 69 deletions
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 5b091fb..1d03ec0 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -1727,19 +1727,22 @@ def _check_tracemalloc():
def check_free_after_iterating(test, iter, cls, args=()):
- class A(cls):
- def __del__(self):
- nonlocal done
- done = True
- try:
- next(it)
- except StopIteration:
- pass
-
done = False
- it = iter(A(*args))
- # Issue 26494: Shouldn't crash
- test.assertRaises(StopIteration, next, it)
+ def wrapper():
+ class A(cls):
+ def __del__(self):
+ nonlocal done
+ done = True
+ try:
+ next(it)
+ except StopIteration:
+ pass
+
+ it = iter(A(*args))
+ # Issue 26494: Shouldn't crash
+ test.assertRaises(StopIteration, next, it)
+
+ wrapper()
# The sequence should be deallocated just after the end of iterating
gc_collect()
test.assertTrue(done)
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 30aedb0..9606d5b 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -302,7 +302,7 @@ class TestCase(unittest.TestCase):
# listiter_reduce_general
self.assertEqual(
run("reversed", orig["reversed"](list(range(8)))),
- (iter, ([],))
+ (reversed, ([],))
)
for case in types:
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-02-14-23-50-55.gh-issue-112087.H_4W_v.rst b/Misc/NEWS.d/next/Core and Builtins/2024-02-14-23-50-55.gh-issue-112087.H_4W_v.rst
new file mode 100644
index 0000000..f92cdaf
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2024-02-14-23-50-55.gh-issue-112087.H_4W_v.rst
@@ -0,0 +1,2 @@
+For an empty reverse iterator for list will be reduced to :func:`reversed`.
+Patch by Donghee Na
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 93409a8..96182a4 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -20,6 +20,14 @@ class list "PyListObject *" "&PyList_Type"
_Py_DECLARE_STR(list_err, "list index out of range");
+#ifdef Py_GIL_DISABLED
+# define LOAD_SSIZE(value) _Py_atomic_load_ssize_relaxed(&value)
+# define STORE_SSIZE(value, new_value) _Py_atomic_store_ssize_relaxed(&value, new_value)
+#else
+# define LOAD_SSIZE(value) value
+# define STORE_SSIZE(value, new_value) value = new_value
+#endif
+
#ifdef WITH_FREELISTS
static struct _Py_list_freelist *
get_list_freelist(void)
@@ -2971,7 +2979,8 @@ list___sizeof___impl(PyListObject *self)
/*[clinic end generated code: output=3417541f95f9a53e input=b8030a5d5ce8a187]*/
{
size_t res = _PyObject_SIZE(Py_TYPE(self));
- res += (size_t)self->allocated * sizeof(void*);
+ Py_ssize_t allocated = LOAD_SSIZE(self->allocated);
+ res += (size_t)allocated * sizeof(void*);
return PyLong_FromSize_t(res);
}
@@ -3373,33 +3382,34 @@ static PyObject *
listiter_next(PyObject *self)
{
_PyListIterObject *it = (_PyListIterObject *)self;
- PyListObject *seq;
- PyObject *item;
-
- assert(it != NULL);
- seq = it->it_seq;
- if (seq == NULL)
+ Py_ssize_t index = LOAD_SSIZE(it->it_index);
+ if (index < 0) {
return NULL;
- assert(PyList_Check(seq));
-
- if (it->it_index < PyList_GET_SIZE(seq)) {
- item = PyList_GET_ITEM(seq, it->it_index);
- ++it->it_index;
- return Py_NewRef(item);
}
- it->it_seq = NULL;
- Py_DECREF(seq);
- return NULL;
+ PyObject *item = list_get_item_ref(it->it_seq, index);
+ if (item == NULL) {
+ // out-of-bounds
+ STORE_SSIZE(it->it_index, -1);
+#ifndef Py_GIL_DISABLED
+ PyListObject *seq = it->it_seq;
+ it->it_seq = NULL;
+ Py_DECREF(seq);
+#endif
+ return NULL;
+ }
+ STORE_SSIZE(it->it_index, index + 1);
+ return item;
}
static PyObject *
listiter_len(PyObject *self, PyObject *Py_UNUSED(ignored))
{
+ assert(self != NULL);
_PyListIterObject *it = (_PyListIterObject *)self;
- Py_ssize_t len;
- if (it->it_seq) {
- len = PyList_GET_SIZE(it->it_seq) - it->it_index;
+ Py_ssize_t index = LOAD_SSIZE(it->it_index);
+ if (index >= 0) {
+ Py_ssize_t len = PyList_GET_SIZE(it->it_seq) - index;
if (len >= 0)
return PyLong_FromSsize_t(len);
}
@@ -3420,8 +3430,8 @@ listiter_setstate(PyObject *self, PyObject *state)
if (index == -1 && PyErr_Occurred())
return NULL;
if (it->it_seq != NULL) {
- if (index < 0)
- index = 0;
+ if (index < -1)
+ index = -1;
else if (index > PyList_GET_SIZE(it->it_seq))
index = PyList_GET_SIZE(it->it_seq); /* iterator exhausted */
it->it_index = index;
@@ -3526,26 +3536,24 @@ static PyObject *
listreviter_next(PyObject *self)
{
listreviterobject *it = (listreviterobject *)self;
- PyObject *item;
- Py_ssize_t index;
- PyListObject *seq;
-
assert(it != NULL);
- seq = it->it_seq;
- if (seq == NULL) {
- return NULL;
- }
+ PyListObject *seq = it->it_seq;
assert(PyList_Check(seq));
- index = it->it_index;
- if (index>=0 && index < PyList_GET_SIZE(seq)) {
- item = PyList_GET_ITEM(seq, index);
- it->it_index--;
- return Py_NewRef(item);
+ Py_ssize_t index = LOAD_SSIZE(it->it_index);
+ if (index < 0) {
+ return NULL;
+ }
+ PyObject *item = list_get_item_ref(seq, index);
+ if (item != NULL) {
+ STORE_SSIZE(it->it_index, index - 1);
+ return item;
}
- it->it_index = -1;
+ STORE_SSIZE(it->it_index, -1);
+#ifndef Py_GIL_DISABLED
it->it_seq = NULL;
Py_DECREF(seq);
+#endif
return NULL;
}
@@ -3553,7 +3561,8 @@ static PyObject *
listreviter_len(PyObject *self, PyObject *Py_UNUSED(ignored))
{
listreviterobject *it = (listreviterobject *)self;
- Py_ssize_t len = it->it_index + 1;
+ Py_ssize_t index = LOAD_SSIZE(it->it_index);
+ Py_ssize_t len = index + 1;
if (it->it_seq == NULL || PyList_GET_SIZE(it->it_seq) < len)
len = 0;
return PyLong_FromSsize_t(len);
@@ -3588,6 +3597,7 @@ static PyObject *
listiter_reduce_general(void *_it, int forward)
{
PyObject *list;
+ PyObject *iter;
/* _PyEval_GetBuiltin can invoke arbitrary code,
* call must be before access of iterator pointers.
@@ -3595,29 +3605,21 @@ listiter_reduce_general(void *_it, int forward)
/* the objects are not the same, index is of different types! */
if (forward) {
- PyObject *iter = _PyEval_GetBuiltin(&_Py_ID(iter));
- if (!iter) {
- return NULL;
- }
+ iter = _PyEval_GetBuiltin(&_Py_ID(iter));
_PyListIterObject *it = (_PyListIterObject *)_it;
- if (it->it_seq) {
+ if (it->it_index >= 0) {
return Py_BuildValue("N(O)n", iter, it->it_seq, it->it_index);
}
- Py_DECREF(iter);
} else {
- PyObject *reversed = _PyEval_GetBuiltin(&_Py_ID(reversed));
- if (!reversed) {
- return NULL;
- }
+ iter = _PyEval_GetBuiltin(&_Py_ID(reversed));
listreviterobject *it = (listreviterobject *)_it;
- if (it->it_seq) {
- return Py_BuildValue("N(O)n", reversed, it->it_seq, it->it_index);
+ if (it->it_index >= 0) {
+ return Py_BuildValue("N(O)n", iter, it->it_seq, it->it_index);
}
- Py_DECREF(reversed);
}
/* empty iterator, create an empty list */
list = PyList_New(0);
if (list == NULL)
return NULL;
- return Py_BuildValue("N(N)", _PyEval_GetBuiltin(&_Py_ID(iter)), list);
+ return Py_BuildValue("N(N)", iter, list);
}
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 96b97ca..28ade64 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2606,11 +2606,14 @@ dummy_func(
assert(Py_TYPE(iter) == &PyListIter_Type);
STAT_INC(FOR_ITER, hit);
PyListObject *seq = it->it_seq;
- if (seq == NULL || it->it_index >= PyList_GET_SIZE(seq)) {
+ if ((size_t)it->it_index >= (size_t)PyList_GET_SIZE(seq)) {
+ it->it_index = -1;
+ #ifndef Py_GIL_DISABLED
if (seq != NULL) {
it->it_seq = NULL;
Py_DECREF(seq);
}
+ #endif
Py_DECREF(iter);
STACK_SHRINK(1);
/* Jump forward oparg, then skip following END_FOR and POP_TOP instructions */
@@ -2624,8 +2627,7 @@ dummy_func(
_PyListIterObject *it = (_PyListIterObject *)iter;
assert(Py_TYPE(iter) == &PyListIter_Type);
PyListObject *seq = it->it_seq;
- DEOPT_IF(seq == NULL);
- DEOPT_IF(it->it_index >= PyList_GET_SIZE(seq));
+ DEOPT_IF((size_t)it->it_index >= (size_t)PyList_GET_SIZE(seq));
}
op(_ITER_NEXT_LIST, (iter -- iter, next)) {
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index 58d2383..7a0e0e4 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -2201,8 +2201,7 @@
_PyListIterObject *it = (_PyListIterObject *)iter;
assert(Py_TYPE(iter) == &PyListIter_Type);
PyListObject *seq = it->it_seq;
- if (seq == NULL) goto deoptimize;
- if (it->it_index >= PyList_GET_SIZE(seq)) goto deoptimize;
+ if ((size_t)it->it_index >= (size_t)PyList_GET_SIZE(seq)) goto deoptimize;
break;
}
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index a49223e..177bc32 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -2541,11 +2541,14 @@
assert(Py_TYPE(iter) == &PyListIter_Type);
STAT_INC(FOR_ITER, hit);
PyListObject *seq = it->it_seq;
- if (seq == NULL || it->it_index >= PyList_GET_SIZE(seq)) {
+ if ((size_t)it->it_index >= (size_t)PyList_GET_SIZE(seq)) {
+ it->it_index = -1;
+ #ifndef Py_GIL_DISABLED
if (seq != NULL) {
it->it_seq = NULL;
Py_DECREF(seq);
}
+ #endif
Py_DECREF(iter);
STACK_SHRINK(1);
/* Jump forward oparg, then skip following END_FOR and POP_TOP instructions */
generated by cgit v0.12 at 2025-08-08 08:20:50 (GMT)