This is Pete Shinners' patch from his bug report
[ 984722 ] Py_BuildValue loses reference counts on error
I'm ever-so-slightly uneasy at the amount of work this can do with an
exception pending, but I don't think that this can result in anything
more serious than a strange error message.
diff --git a/Python/modsupport.c b/Python/modsupport.c
index f26d7b8..197d99b 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -152,28 +152,32 @@
{
PyObject *d;
int i;
+ int itemfailed = 0;
if (n < 0)
return NULL;
if ((d = PyDict_New()) == NULL)
return NULL;
+ /* Note that we can't bail immediately on error as this will leak
+ refcounts on any 'N' arguments. */
for (i = 0; i < n; i+= 2) {
PyObject *k, *v;
int err;
k = do_mkvalue(p_format, p_va);
if (k == NULL) {
- Py_DECREF(d);
- return NULL;
+ itemfailed = 1;
+ Py_INCREF(Py_None);
+ k = Py_None;
}
v = do_mkvalue(p_format, p_va);
if (v == NULL) {
- Py_DECREF(k);
- Py_DECREF(d);
- return NULL;
+ itemfailed = 1;
+ Py_INCREF(Py_None);
+ v = Py_None;
}
err = PyDict_SetItem(d, k, v);
Py_DECREF(k);
Py_DECREF(v);
- if (err < 0) {
+ if (err < 0 || itemfailed) {
Py_DECREF(d);
return NULL;
}
@@ -194,15 +198,19 @@
{
PyObject *v;
int i;
+ int itemfailed = 0;
if (n < 0)
return NULL;
if ((v = PyList_New(n)) == NULL)
return NULL;
+ /* Note that we can't bail immediately on error as this will leak
+ refcounts on any 'N' arguments. */
for (i = 0; i < n; i++) {
PyObject *w = do_mkvalue(p_format, p_va);
if (w == NULL) {
- Py_DECREF(v);
- return NULL;
+ itemfailed = 1;
+ Py_INCREF(Py_None);
+ w = Py_None;
}
PyList_SetItem(v, i, w);
}
@@ -214,6 +222,10 @@
}
else if (endchar)
++*p_format;
+ if (itemfailed) {
+ Py_DECREF(v);
+ v = NULL;
+ }
return v;
}
@@ -233,15 +245,19 @@
{
PyObject *v;
int i;
+ int itemfailed = 0;
if (n < 0)
return NULL;
if ((v = PyTuple_New(n)) == NULL)
return NULL;
+ /* Note that we can't bail immediately on error as this will leak
+ refcounts on any 'N' arguments. */
for (i = 0; i < n; i++) {
PyObject *w = do_mkvalue(p_format, p_va);
if (w == NULL) {
- Py_DECREF(v);
- return NULL;
+ itemfailed = 1;
+ Py_INCREF(Py_None);
+ w = Py_None;
}
PyTuple_SetItem(v, i, w);
}
@@ -253,6 +269,10 @@
}
else if (endchar)
++*p_format;
+ if (itemfailed) {
+ Py_DECREF(v);
+ v = NULL;
+ }
return v;
}