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authorAntoine Pitrou <solipsis@pitrou.net>2012-11-01 18:59:21 (GMT)
committerAntoine Pitrou <solipsis@pitrou.net>2012-11-01 18:59:21 (GMT)
commit5ebe65f8cb541b10f07fb6ce2b4283a26c7e1d80 (patch)
treeeb43876e2c023c255b26cb6d79b188079f573f6f
parent90c0eb28c5ff1da76b258f9cf6a54abc6df19675 (diff)
parent9f69e79c450c3c17172046f937941e6df1802a6d (diff)
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Issue #16228: Fix a crash in the json module where a list changes size while it is being encoded.
Patch by Serhiy Storchaka.
-rw-r--r--Lib/test/json_tests/test_dump.py8
-rw-r--r--Misc/NEWS3
-rw-r--r--Modules/_json.c10
3 files changed, 14 insertions, 7 deletions
diff --git a/Lib/test/json_tests/test_dump.py b/Lib/test/json_tests/test_dump.py
index 4b3386f..237ee35 100644
--- a/Lib/test/json_tests/test_dump.py
+++ b/Lib/test/json_tests/test_dump.py
@@ -20,6 +20,14 @@ class TestDump:
{2: 3.0, 4.0: 5, False: 1, 6: True}, sort_keys=True),
'{"false": 1, "2": 3.0, "4.0": 5, "6": true}')
+ # Issue 16228: Crash on encoding resized list
+ def test_encode_mutated(self):
+ a = [object()] * 10
+ def crasher(obj):
+ del a[-1]
+ self.assertEqual(self.dumps(a, default=crasher),
+ '[null, null, null, null, null]')
+
class TestPyDump(TestDump, PyTest): pass
diff --git a/Misc/NEWS b/Misc/NEWS
index 845375d..5dc8437 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -61,6 +61,9 @@ Core and Builtins
Library
-------
+- Issue #16228: Fix a crash in the json module where a list changes size
+ while it is being encoded. Patch by Serhiy Storchaka.
+
- Issue #14897: Enhance error messages of struct.pack and
struct.pack_into. Patch by Matti Mäki.
diff --git a/Modules/_json.c b/Modules/_json.c
index fb8bd59..5b42f6f 100644
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -1660,8 +1660,6 @@ encoder_listencode_list(PyEncoderObject *s, _PyAccu *acc,
static PyObject *empty_array = NULL;
PyObject *ident = NULL;
PyObject *s_fast = NULL;
- Py_ssize_t num_items;
- PyObject **seq_items;
Py_ssize_t i;
if (open_array == NULL || close_array == NULL || empty_array == NULL) {
@@ -1675,8 +1673,7 @@ encoder_listencode_list(PyEncoderObject *s, _PyAccu *acc,
s_fast = PySequence_Fast(seq, "_iterencode_list needs a sequence");
if (s_fast == NULL)
return -1;
- num_items = PySequence_Fast_GET_SIZE(s_fast);
- if (num_items == 0) {
+ if (PySequence_Fast_GET_SIZE(s_fast) == 0) {
Py_DECREF(s_fast);
return _PyAccu_Accumulate(acc, empty_array);
}
@@ -1697,7 +1694,6 @@ encoder_listencode_list(PyEncoderObject *s, _PyAccu *acc,
}
}
- seq_items = PySequence_Fast_ITEMS(s_fast);
if (_PyAccu_Accumulate(acc, open_array))
goto bail;
if (s->indent != Py_None) {
@@ -1709,8 +1705,8 @@ encoder_listencode_list(PyEncoderObject *s, _PyAccu *acc,
buf += newline_indent
*/
}
- for (i = 0; i < num_items; i++) {
- PyObject *obj = seq_items[i];
+ for (i = 0; i < PySequence_Fast_GET_SIZE(s_fast); i++) {
+ PyObject *obj = PySequence_Fast_GET_ITEM(s_fast, i);
if (i) {
if (_PyAccu_Accumulate(acc, s->item_separator))
goto bail;