From 65001efd062307e12ca41569681cc59cf4bfa841 Mon Sep 17 00:00:00 2001 From: Stan Ulbrych Date: Wed, 13 May 2026 21:27:03 +0100 Subject: [PATCH] Fix `SystemError` when compiling `__classdict__` class annotation --- Lib/test/test_type_annotations.py | 7 +++++++ .../2026-05-13-21-26-26.gh-issue-149805.IG6cza.rst | 2 ++ Python/symtable.c | 1 + 3 files changed, 10 insertions(+) create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2026-05-13-21-26-26.gh-issue-149805.IG6cza.rst diff --git a/Lib/test/test_type_annotations.py b/Lib/test/test_type_annotations.py index d459f497e333e6..b751f825bb97d5 100644 --- a/Lib/test/test_type_annotations.py +++ b/Lib/test/test_type_annotations.py @@ -485,6 +485,13 @@ def test_comprehension_in_annotation(self): ns = run_code("x: [y for y in range(10)]") self.assertEqual(ns["__annotate__"](1), {"x": list(range(10))}) + def test_class_annotation_dunder_classdict(self): + ns = run_code(""" + class C: + __classdict__: int + """) + self.assertEqual(ns["C"].__annotations__, {"__classdict__": int}) + def test_future_annotations(self): code = """ from __future__ import annotations diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-05-13-21-26-26.gh-issue-149805.IG6cza.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-05-13-21-26-26.gh-issue-149805.IG6cza.rst new file mode 100644 index 00000000000000..02d050840ee1f9 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-05-13-21-26-26.gh-issue-149805.IG6cza.rst @@ -0,0 +1,2 @@ +Fix a :exc:`SystemError` when compiling a compiling ``__classdict__`` class +annotation. Found by OSS-Fuzz in :oss-fuzz:`512907042`. diff --git a/Python/symtable.c b/Python/symtable.c index 2263a2d8db9097..9a2e278caaf9e2 100644 --- a/Python/symtable.c +++ b/Python/symtable.c @@ -2870,6 +2870,7 @@ symtable_visit_annotation(struct symtable *st, expr_ty annotation, void *key) int future_annotations = st->st_future->ff_features & CO_FUTURE_ANNOTATIONS; if (current_type == ClassBlock && !future_annotations) { st->st_cur->ste_can_see_class_scope = 1; + parent_ste->ste_needs_classdict = 1; if (!symtable_add_def(st, &_Py_ID(__classdict__), USE, LOCATION(annotation))) { return 0; }