[Python-checkins] cpython (2.7): Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list
antoine.pitrou
python-checkins at python.org
Mon Mar 4 20:33:55 CET 2013
http://hg.python.org/cpython/rev/21ded74b51fa
changeset: 82478:21ded74b51fa
branch: 2.7
parent: 82475:654136546895
user: Antoine Pitrou <solipsis at pitrou.net>
date: Mon Mar 04 20:30:01 2013 +0100
summary:
Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list is being resized concurrently.
files:
Lib/test/test_heapq.py | 26 +++++++++++++++++++
Misc/NEWS | 3 ++
Modules/_heapqmodule.c | 40 +++++++++++++++++++++++++----
3 files changed, 63 insertions(+), 6 deletions(-)
diff --git a/Lib/test/test_heapq.py b/Lib/test/test_heapq.py
--- a/Lib/test/test_heapq.py
+++ b/Lib/test/test_heapq.py
@@ -315,6 +315,16 @@
'Test multiple tiers of iterators'
return chain(imap(lambda x:x, R(Ig(G(seqn)))))
+class SideEffectLT:
+ def __init__(self, value, heap):
+ self.value = value
+ self.heap = heap
+
+ def __lt__(self, other):
+ self.heap[:] = []
+ return self.value < other.value
+
+
class TestErrorHandling(TestCase):
module = None
@@ -361,6 +371,22 @@
self.assertRaises(TypeError, f, 2, N(s))
self.assertRaises(ZeroDivisionError, f, 2, E(s))
+ # Issue #17278: the heap may change size while it's being walked.
+
+ def test_heappush_mutating_heap(self):
+ heap = []
+ heap.extend(SideEffectLT(i, heap) for i in range(200))
+ # Python version raises IndexError, C version RuntimeError
+ with self.assertRaises((IndexError, RuntimeError)):
+ self.module.heappush(heap, SideEffectLT(5, heap))
+
+ def test_heappop_mutating_heap(self):
+ heap = []
+ heap.extend(SideEffectLT(i, heap) for i in range(200))
+ # Python version raises IndexError, C version RuntimeError
+ with self.assertRaises((IndexError, RuntimeError)):
+ self.module.heappop(heap)
+
class TestErrorHandlingPython(TestErrorHandling):
module = py_heapq
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -214,6 +214,9 @@
Library
-------
+- Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when
+ the list is being resized concurrently.
+
- Issue #17018: Make Process.join() retry if os.waitpid() fails with EINTR.
- Issue #14720: sqlite3: Convert datetime microseconds correctly.
diff --git a/Modules/_heapqmodule.c b/Modules/_heapqmodule.c
--- a/Modules/_heapqmodule.c
+++ b/Modules/_heapqmodule.c
@@ -35,12 +35,14 @@
static int
_siftdown(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
{
- PyObject *newitem, *parent;
+ PyObject *newitem, *parent, *olditem;
int cmp;
Py_ssize_t parentpos;
+ Py_ssize_t size;
assert(PyList_Check(heap));
- if (pos >= PyList_GET_SIZE(heap)) {
+ size = PyList_GET_SIZE(heap);
+ if (pos >= size) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return -1;
}
@@ -57,12 +59,24 @@
Py_DECREF(newitem);
return -1;
}
+ if (size != PyList_GET_SIZE(heap)) {
+ Py_DECREF(newitem);
+ PyErr_SetString(PyExc_RuntimeError,
+ "list changed size during iteration");
+ return -1;
+ }
if (cmp == 0)
break;
Py_INCREF(parent);
- Py_DECREF(PyList_GET_ITEM(heap, pos));
+ olditem = PyList_GET_ITEM(heap, pos);
PyList_SET_ITEM(heap, pos, parent);
+ Py_DECREF(olditem);
pos = parentpos;
+ if (size != PyList_GET_SIZE(heap)) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "list changed size during iteration");
+ return -1;
+ }
}
Py_DECREF(PyList_GET_ITEM(heap, pos));
PyList_SET_ITEM(heap, pos, newitem);
@@ -74,10 +88,12 @@
{
Py_ssize_t startpos, endpos, childpos, rightpos;
int cmp;
- PyObject *newitem, *tmp;
+ PyObject *newitem, *tmp, *olditem;
+ Py_ssize_t size;
assert(PyList_Check(heap));
- endpos = PyList_GET_SIZE(heap);
+ size = PyList_GET_SIZE(heap);
+ endpos = size;
startpos = pos;
if (pos >= endpos) {
PyErr_SetString(PyExc_IndexError, "index out of range");
@@ -102,13 +118,25 @@
if (cmp == 0)
childpos = rightpos;
}
+ if (size != PyList_GET_SIZE(heap)) {
+ Py_DECREF(newitem);
+ PyErr_SetString(PyExc_RuntimeError,
+ "list changed size during iteration");
+ return -1;
+ }
/* Move the smaller child up. */
tmp = PyList_GET_ITEM(heap, childpos);
Py_INCREF(tmp);
- Py_DECREF(PyList_GET_ITEM(heap, pos));
+ olditem = PyList_GET_ITEM(heap, pos);
PyList_SET_ITEM(heap, pos, tmp);
+ Py_DECREF(olditem);
pos = childpos;
childpos = 2*pos + 1;
+ if (size != PyList_GET_SIZE(heap)) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "list changed size during iteration");
+ return -1;
+ }
}
/* The leaf at pos is empty now. Put newitem there, and and bubble
--
Repository URL: http://hg.python.org/cpython
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