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Issue #25902: Fixed various refcount issues in ElementTree iteration.

This commit is contained in:
Serhiy Storchaka 2015-12-21 11:11:12 +02:00
parent 0c477e6a85 66c08d90f6
commit 47a9d59d51
4 changed files with 117 additions and 36 deletions
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51
Lib/test/test_xml_etree.py
View File

@ -1668,6 +1668,57 @@ class BugsTest(unittest.TestCase):
ET.register_namespace('test10777', 'http://myuri/')
ET.register_namespace('test10777', 'http://myuri/')
def test_lost_text(self):
# Issue #25902: Borrowed text can disappear
class Text:
def __bool__(self):
e.text = 'changed'
return True
e = ET.Element('tag')
e.text = Text()
i = e.itertext()
t = next(i)
self.assertIsInstance(t, Text)
self.assertIsInstance(e.text, str)
self.assertEqual(e.text, 'changed')
def test_lost_tail(self):
# Issue #25902: Borrowed tail can disappear
class Text:
def __bool__(self):
e[0].tail = 'changed'
return True
e = ET.Element('root')
e.append(ET.Element('tag'))
e[0].tail = Text()
i = e.itertext()
t = next(i)
self.assertIsInstance(t, Text)
self.assertIsInstance(e[0].tail, str)
self.assertEqual(e[0].tail, 'changed')
def test_lost_elem(self):
# Issue #25902: Borrowed element can disappear
class Tag:
def __eq__(self, other):
e[0] = ET.Element('changed')
next(i)
return True
e = ET.Element('root')
e.append(ET.Element(Tag()))
e.append(ET.Element('tag'))
i = e.iter('tag')
try:
t = next(i)
except ValueError:
self.skipTest('generators are not reentrant')
self.assertIsInstance(t.tag, Tag)
self.assertIsInstance(e[0].tag, str)
self.assertEqual(e[0].tag, 'changed')
# --------------------------------------------------------------------

10
Lib/xml/etree/ElementTree.py
View File

@ -429,12 +429,14 @@ class Element:
tag = self.tag
if not isinstance(tag, str) and tag is not None:
return
if self.text:
yield self.text
t = self.text
if t:
yield t
for e in self:
yield from e.itertext()
if e.tail:
yield e.tail
t = e.tail
if t:
yield t
def SubElement(parent, tag, attrib={}, **extra):

2
Misc/NEWS
View File

@ -115,6 +115,8 @@ Core and Builtins
Library
-------
- Issue #25902: Fixed various refcount issues in ElementTree iteration.
- Issue #22227: The TarFile iterator is reimplemented using generator.
This implementation is simpler that using class.

90
Modules/_elementtree.c
View File

@ -2070,6 +2070,7 @@ elementiter_next(ElementIterObject *it)
ElementObject *cur_parent;
Py_ssize_t child_index;
int rc;
ElementObject *elem;
while (1) {
/* Handle the case reached in the beginning and end of iteration, where
@ -2083,38 +2084,47 @@ elementiter_next(ElementIterObject *it)
PyErr_SetNone(PyExc_StopIteration);
return NULL;
} else {
elem = it->root_element;
it->parent_stack = parent_stack_push_new(it->parent_stack,
it->root_element);
elem);
if (!it->parent_stack) {
PyErr_NoMemory();
return NULL;
}
Py_INCREF(elem);
it->root_done = 1;
rc = (it->sought_tag == Py_None);
if (!rc) {
rc = PyObject_RichCompareBool(it->root_element->tag,
rc = PyObject_RichCompareBool(elem->tag,
it->sought_tag, Py_EQ);
if (rc < 0)
if (rc < 0) {
Py_DECREF(elem);
return NULL;
}
}
if (rc) {
if (it->gettext) {
PyObject *text = element_get_text(it->root_element);
if (!text)
PyObject *text = element_get_text(elem);
if (!text) {
Py_DECREF(elem);
return NULL;
}
Py_INCREF(text);
Py_DECREF(elem);
rc = PyObject_IsTrue(text);
if (rc > 0)
return text;
Py_DECREF(text);
if (rc < 0)
return NULL;
if (rc) {
Py_INCREF(text);
return text;
}
} else {
Py_INCREF(it->root_element);
return (PyObject *)it->root_element;
return (PyObject *)elem;
}
}
else {
Py_DECREF(elem);
}
}
}
@ -2124,54 +2134,68 @@ elementiter_next(ElementIterObject *it)
cur_parent = it->parent_stack->parent;
child_index = it->parent_stack->child_index;
if (cur_parent->extra && child_index < cur_parent->extra->length) {
ElementObject *child = (ElementObject *)
cur_parent->extra->children[child_index];
elem = (ElementObject *)cur_parent->extra->children[child_index];
it->parent_stack->child_index++;
it->parent_stack = parent_stack_push_new(it->parent_stack,
child);
elem);
if (!it->parent_stack) {
PyErr_NoMemory();
return NULL;
}
Py_INCREF(elem);
if (it->gettext) {
PyObject *text = element_get_text(child);
if (!text)
PyObject *text = element_get_text(elem);
if (!text) {
Py_DECREF(elem);
return NULL;
}
Py_INCREF(text);
Py_DECREF(elem);
rc = PyObject_IsTrue(text);
if (rc > 0)
return text;
Py_DECREF(text);
if (rc < 0)
return NULL;
if (rc) {
Py_INCREF(text);
return text;
}
} else {
rc = (it->sought_tag == Py_None);
if (!rc) {
rc = PyObject_RichCompareBool(child->tag,
rc = PyObject_RichCompareBool(elem->tag,
it->sought_tag, Py_EQ);
if (rc < 0)
if (rc < 0) {
Py_DECREF(elem);
return NULL;
}
}
if (rc) {
Py_INCREF(child);
return (PyObject *)child;
return (PyObject *)elem;
}
Py_DECREF(elem);
}
}
else {
PyObject *tail;
ParentLocator *next = it->parent_stack->next;
ParentLocator *next;
if (it->gettext) {
Py_INCREF(cur_parent);
tail = element_get_tail(cur_parent);
if (!tail)
if (!tail) {
Py_DECREF(cur_parent);
return NULL;
}
Py_INCREF(tail);
Py_DECREF(cur_parent);
}
else
else {
tail = Py_None;
Py_XDECREF(it->parent_stack->parent);
Py_INCREF(tail);
}
next = it->parent_stack->next;
cur_parent = it->parent_stack->parent;
PyObject_Free(it->parent_stack);
it->parent_stack = next;
Py_XDECREF(cur_parent);
/* Note that extra condition on it->parent_stack->parent here;
* this is because itertext() is supposed to only return *inner*
@ -2179,12 +2203,14 @@ elementiter_next(ElementIterObject *it)
*/
if (it->parent_stack->parent) {
rc = PyObject_IsTrue(tail);
if (rc > 0)
return tail;
Py_DECREF(tail);
if (rc < 0)
return NULL;
if (rc) {
Py_INCREF(tail);
return tail;
}
}
else {
Py_DECREF(tail);
}
}
}