https://github.com/python/cpython/commit/b2eaa75b176e07730215d76d8dce4d63fb493391
commit: b2eaa75b176e07730215d76d8dce4d63fb493391
branch: main
author: sobolevn <[email protected]>
committer: Eclips4 <[email protected]>
date: 2024-10-29T17:42:48+02:00
summary:
gh-126105: Fix crash in `ast` module, when `._fields` is deleted (#126115)
Previously, if the `ast.AST._fields` attribute was deleted, attempts to create
a new `as`t node would crash due to the assumption that `_fields` always had a
non-NULL value. Now it has been fixed by adding an extra check to ensure that
`_fields` does not have a NULL value (this can happen when you manually remove
`_fields` attribute).
files:
A Misc/NEWS.d/next/Library/2024-10-29-11-45-44.gh-issue-126105.cOL-R6.rst
M Lib/test/test_ast/test_ast.py
M Parser/asdl_c.py
M Python/Python-ast.c
diff --git a/Lib/test/test_ast/test_ast.py b/Lib/test/test_ast/test_ast.py
index 739a020f708004..67ab8cf6baf657 100644
--- a/Lib/test/test_ast/test_ast.py
+++ b/Lib/test/test_ast/test_ast.py
@@ -84,6 +84,23 @@ def test_AST_objects(self):
# "ast.AST constructor takes 0 positional arguments"
ast.AST(2)
+ def test_AST_fields_NULL_check(self):
+ # See: https://github.com/python/cpython/issues/126105
+ old_value = ast.AST._fields
+
+ def cleanup():
+ ast.AST._fields = old_value
+ self.addCleanup(cleanup)
+
+ del ast.AST._fields
+
+ msg = "type object 'ast.AST' has no attribute '_fields'"
+ # Both examples used to crash:
+ with self.assertRaisesRegex(AttributeError, msg):
+ ast.AST(arg1=123)
+ with self.assertRaisesRegex(AttributeError, msg):
+ ast.AST()
+
def test_AST_garbage_collection(self):
class X:
pass
diff --git
a/Misc/NEWS.d/next/Library/2024-10-29-11-45-44.gh-issue-126105.cOL-R6.rst
b/Misc/NEWS.d/next/Library/2024-10-29-11-45-44.gh-issue-126105.cOL-R6.rst
new file mode 100644
index 00000000000000..547eb3af1ca064
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-10-29-11-45-44.gh-issue-126105.cOL-R6.rst
@@ -0,0 +1 @@
+Fix a crash in :mod:`ast` when the :attr:`ast.AST._fields` attribute is
deleted.
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index 32eac3afafa5d5..853a3e99807bca 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -884,19 +884,17 @@ def visitModule(self, mod):
Py_ssize_t i, numfields = 0;
int res = -1;
PyObject *key, *value, *fields, *attributes = NULL, *remaining_fields =
NULL;
- if (PyObject_GetOptionalAttr((PyObject*)Py_TYPE(self), state->_fields,
&fields) < 0) {
+
+ fields = PyObject_GetAttr((PyObject*)Py_TYPE(self), state->_fields);
+ if (fields == NULL) {
goto cleanup;
}
- if (fields) {
- numfields = PySequence_Size(fields);
- if (numfields == -1) {
- goto cleanup;
- }
- remaining_fields = PySet_New(fields);
- }
- else {
- remaining_fields = PySet_New(NULL);
+
+ numfields = PySequence_Size(fields);
+ if (numfields == -1) {
+ goto cleanup;
}
+ remaining_fields = PySet_New(fields);
if (remaining_fields == NULL) {
goto cleanup;
}
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 38d74b48d232f8..41299b29705848 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -5083,19 +5083,17 @@ ast_type_init(PyObject *self, PyObject *args, PyObject
*kw)
Py_ssize_t i, numfields = 0;
int res = -1;
PyObject *key, *value, *fields, *attributes = NULL, *remaining_fields =
NULL;
- if (PyObject_GetOptionalAttr((PyObject*)Py_TYPE(self), state->_fields,
&fields) < 0) {
+
+ fields = PyObject_GetAttr((PyObject*)Py_TYPE(self), state->_fields);
+ if (fields == NULL) {
goto cleanup;
}
- if (fields) {
- numfields = PySequence_Size(fields);
- if (numfields == -1) {
- goto cleanup;
- }
- remaining_fields = PySet_New(fields);
- }
- else {
- remaining_fields = PySet_New(NULL);
+
+ numfields = PySequence_Size(fields);
+ if (numfields == -1) {
+ goto cleanup;
}
+ remaining_fields = PySet_New(fields);
if (remaining_fields == NULL) {
goto cleanup;
}
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