Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when the list is being resized concurrently.
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31584e30ab
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@ -319,6 +319,16 @@ def L(seqn):
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return chain(map(lambda x:x, R(Ig(G(seqn)))))
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class SideEffectLT:
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def __init__(self, value, heap):
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self.value = value
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self.heap = heap
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def __lt__(self, other):
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self.heap[:] = []
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return self.value < other.value
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class TestErrorHandling:
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def test_non_sequence(self):
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@ -369,6 +379,22 @@ class TestErrorHandling:
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self.assertRaises(TypeError, f, 2, N(s))
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self.assertRaises(ZeroDivisionError, f, 2, E(s))
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# Issue #17278: the heap may change size while it's being walked.
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def test_heappush_mutating_heap(self):
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heap = []
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heap.extend(SideEffectLT(i, heap) for i in range(200))
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# Python version raises IndexError, C version RuntimeError
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with self.assertRaises((IndexError, RuntimeError)):
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self.module.heappush(heap, SideEffectLT(5, heap))
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def test_heappop_mutating_heap(self):
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heap = []
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heap.extend(SideEffectLT(i, heap) for i in range(200))
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# Python version raises IndexError, C version RuntimeError
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with self.assertRaises((IndexError, RuntimeError)):
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self.module.heappop(heap)
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class TestErrorHandlingPython(TestErrorHandling, TestCase):
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module = py_heapq
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@ -193,6 +193,9 @@ Core and Builtins
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Library
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-------
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- Issue #17278: Fix a crash in heapq.heappush() and heapq.heappop() when
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the list is being resized concurrently.
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- Issue #16962: Use getdents64 instead of the obsolete getdents syscall
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in the subprocess module on Linux.
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@ -11,12 +11,14 @@ annotated by François Pinard, and converted to C by Raymond Hettinger.
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static int
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_siftdown(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
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{
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PyObject *newitem, *parent;
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PyObject *newitem, *parent, *olditem;
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int cmp;
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Py_ssize_t parentpos;
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Py_ssize_t size;
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assert(PyList_Check(heap));
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if (pos >= PyList_GET_SIZE(heap)) {
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size = PyList_GET_SIZE(heap);
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if (pos >= size) {
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PyErr_SetString(PyExc_IndexError, "index out of range");
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return -1;
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}
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@ -33,12 +35,24 @@ _siftdown(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
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Py_DECREF(newitem);
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return -1;
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}
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if (size != PyList_GET_SIZE(heap)) {
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Py_DECREF(newitem);
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PyErr_SetString(PyExc_RuntimeError,
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"list changed size during iteration");
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return -1;
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}
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if (cmp == 0)
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break;
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Py_INCREF(parent);
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Py_DECREF(PyList_GET_ITEM(heap, pos));
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olditem = PyList_GET_ITEM(heap, pos);
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PyList_SET_ITEM(heap, pos, parent);
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Py_DECREF(olditem);
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pos = parentpos;
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if (size != PyList_GET_SIZE(heap)) {
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PyErr_SetString(PyExc_RuntimeError,
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"list changed size during iteration");
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return -1;
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}
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}
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Py_DECREF(PyList_GET_ITEM(heap, pos));
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PyList_SET_ITEM(heap, pos, newitem);
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@ -50,10 +64,12 @@ _siftup(PyListObject *heap, Py_ssize_t pos)
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{
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Py_ssize_t startpos, endpos, childpos, rightpos;
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int cmp;
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PyObject *newitem, *tmp;
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PyObject *newitem, *tmp, *olditem;
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Py_ssize_t size;
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assert(PyList_Check(heap));
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endpos = PyList_GET_SIZE(heap);
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size = PyList_GET_SIZE(heap);
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endpos = size;
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startpos = pos;
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if (pos >= endpos) {
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PyErr_SetString(PyExc_IndexError, "index out of range");
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@ -79,13 +95,25 @@ _siftup(PyListObject *heap, Py_ssize_t pos)
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if (cmp == 0)
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childpos = rightpos;
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}
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if (size != PyList_GET_SIZE(heap)) {
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Py_DECREF(newitem);
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PyErr_SetString(PyExc_RuntimeError,
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"list changed size during iteration");
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return -1;
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}
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/* Move the smaller child up. */
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tmp = PyList_GET_ITEM(heap, childpos);
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Py_INCREF(tmp);
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Py_DECREF(PyList_GET_ITEM(heap, pos));
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olditem = PyList_GET_ITEM(heap, pos);
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PyList_SET_ITEM(heap, pos, tmp);
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Py_DECREF(olditem);
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pos = childpos;
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childpos = 2*pos + 1;
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if (size != PyList_GET_SIZE(heap)) {
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PyErr_SetString(PyExc_RuntimeError,
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"list changed size during iteration");
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return -1;
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}
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}
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/* The leaf at pos is empty now. Put newitem there, and and bubble
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