[Python-checkins] bpo-35441: Remove dead and buggy code related to PyList_SetItem(). (GH-11033)

Sat Dec 8 09:17:03 EST 2018

https://github.com/python/cpython/commit/99d56b53560b3867844472ae381fb3f858760621
commit: 99d56b53560b3867844472ae381fb3f858760621
branch: master
author: Zackery Spytz <zspytz at gmail.com>
committer: Serhiy Storchaka <storchaka at gmail.com>
date: 2018年12月08日T16:16:55+02:00
summary:
bpo-35441: Remove dead and buggy code related to PyList_SetItem(). (GH-11033)
In _localemodule.c and selectmodule.c, remove dead code that would
cause double decrefs if run.
In addition, replace PyList_SetItem() with PyList_SET_ITEM() in cases
where a new list is populated and there is no possibility of an error.
In addition, check if the list changed size in the loop in array_array_fromlist().
files:
M Modules/_localemodule.c
M Modules/arraymodule.c
M Modules/readline.c
M Modules/selectmodule.c
M PC/winreg.c
M Python/ceval.c
M Python/sysmodule.c

diff --git a/Modules/_localemodule.c b/Modules/_localemodule.c
index 4202cc401414..96ca68af178c 100644
--- a/Modules/_localemodule.c
+++ b/Modules/_localemodule.c
@@ -71,20 +71,13 @@ copy_grouping(const char* s)
 do {
 i++;
 val = PyLong_FromLong(s[i]);
- if (!val)
- break;
- if (PyList_SetItem(result, i, val)) {
- Py_DECREF(val);
- val = NULL;
- break;
+ if (val == NULL) {
+ Py_DECREF(result);
+ return NULL;
 }
+ PyList_SET_ITEM(result, i, val);
 } while (s[i] != '0円' && s[i] != CHAR_MAX);
 
- if (!val) {
- Py_DECREF(result);
- return NULL;
- }
-
 return result;
 }
 
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 6a9ff3ec6252..aa7a4fb23c68 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -1544,12 +1544,18 @@ array_array_fromlist(arrayobject *self, PyObject *list)
 if (array_resize(self, old_size + n) == -1)
 return NULL;
 for (i = 0; i < n; i++) {
- PyObject *v = PyList_GetItem(list, i);
+ PyObject *v = PyList_GET_ITEM(list, i);
 if ((*self->ob_descr->setitem)(self,
 Py_SIZE(self) - n + i, v) != 0) {
 array_resize(self, old_size);
 return NULL;
 }
+ if (n != PyList_GET_SIZE(list)) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "list changed size during iteration");
+ array_resize(self, old_size);
+ return NULL;
+ }
 }
 }
 Py_RETURN_NONE;
@@ -1574,8 +1580,7 @@ array_array_tolist_impl(arrayobject *self)
 PyObject *v = getarrayitem((PyObject *)self, i);
 if (v == NULL)
 goto error;
- if (PyList_SetItem(list, i, v) < 0)
- goto error;
+ PyList_SET_ITEM(list, i, v);
 }
 return list;
 
diff --git a/Modules/readline.c b/Modules/readline.c
index 7f366aabfb4f..57335fe911bf 100644
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -936,8 +936,7 @@ on_completion_display_matches_hook(char **matches,
 s = decode(matches[i+1]);
 if (s == NULL)
 goto error;
- if (PyList_SetItem(m, i, s) == -1)
- goto error;
+ PyList_SET_ITEM(m, i, s);
 }
 sub = decode(matches[0]);
 r = PyObject_CallFunction(readlinestate_global->completion_display_matches_hook,
diff --git a/Modules/selectmodule.c b/Modules/selectmodule.c
index fe69cd58dc6a..7f62ab111d1f 100644
--- a/Modules/selectmodule.c
+++ b/Modules/selectmodule.c
@@ -693,10 +693,7 @@ select_poll_poll_impl(pollObject *self, PyObject *timeout_obj)
 goto error;
 }
 PyTuple_SET_ITEM(value, 1, num);
- if ((PyList_SetItem(result_list, j, value)) == -1) {
- Py_DECREF(value);
- goto error;
- }
+ PyList_SET_ITEM(result_list, j, value);
 i++;
 }
 return result_list;
@@ -986,10 +983,7 @@ select_devpoll_poll_impl(devpollObject *self, PyObject *timeout_obj)
 Py_DECREF(num2);
 if (value == NULL)
 goto error;
- if ((PyList_SetItem(result_list, i, value)) == -1) {
- Py_DECREF(value);
- goto error;
- }
+ PyList_SET_ITEM(result_list, i, value);
 }
 
 return result_list;
diff --git a/PC/winreg.c b/PC/winreg.c
index 0198097a1c92..4505c314d7b4 100644
--- a/PC/winreg.c
+++ b/PC/winreg.c
@@ -756,9 +756,13 @@ Reg2Py(BYTE *retDataBuf, DWORD retDataSize, DWORD typ)
 PyMem_Free(str);
 return NULL;
 }
- PyList_SetItem(obData,
- index,
- PyUnicode_FromWideChar(str[index], len));
+ PyObject *uni = PyUnicode_FromWideChar(str[index], len);
+ if (uni == NULL) {
+ Py_DECREF(obData);
+ PyMem_Free(str);
+ return NULL;
+ }
+ PyList_SET_ITEM(obData, index, uni);
 }
 PyMem_Free(str);
 
diff --git a/Python/ceval.c b/Python/ceval.c
index a4273adee48d..7ffc68a1e1fc 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -5124,7 +5124,7 @@ getarray(long a[256])
 Py_DECREF(l);
 return NULL;
 }
- PyList_SetItem(l, i, x);
+ PyList_SET_ITEM(l, i, x);
 }
 for (i = 0; i < 256; i++)
 a[i] = 0;
@@ -5146,7 +5146,7 @@ _Py_GetDXProfile(PyObject *self, PyObject *args)
 Py_DECREF(l);
 return NULL;
 }
- PyList_SetItem(l, i, x);
+ PyList_SET_ITEM(l, i, x);
 }
 return l;
 #endif
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 0ca3de39f8bd..49fa3842b583 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -2594,7 +2594,7 @@ makepathobject(const wchar_t *path, wchar_t delim)
 Py_DECREF(v);
 return NULL;
 }
- PyList_SetItem(v, i, w);
+ PyList_SET_ITEM(v, i, w);
 if (*p == '0円')
 break;
 path = p+1;
