Prevent calling the dealloc slot of a non-GC base class with GC tracking enabled. (GH-5432)

This shows warnings in CPython (3.12) debug builds and can lead to crashes when GC triggers on an object while deallocating it.

1 files changed, 38 insertions, 0 deletions

diff --git a/tests/run/exttype_gc.pyx b/tests/run/exttype_gc.pyx
new file mode 100644
index 000000000..db8ae2cc9
--- /dev/null
+++ b/tests/run/exttype_gc.pyx
@@ -0,0 +1,38 @@
+# mode: run
+# tag: gc
+
+
+def create_obj(cls):
+    cls()  # create and discard
+
+
+cdef class BaseTypeNoGC:
+    pass
+
+
+cdef class ExtTypeGC(BaseTypeNoGC):
+    """
+    >>> create_obj(ExtTypeGC)
+    >>> create_obj(ExtTypeGC)
+    >>> create_obj(ExtTypeGC)
+
+    >>> class PyExtTypeGC(ExtTypeGC): pass
+    >>> create_obj(PyExtTypeGC)
+    >>> create_obj(PyExtTypeGC)
+    >>> create_obj(PyExtTypeGC)
+    """
+    cdef object attr
+
+
+cdef class ExtTypeNoGC(BaseTypeNoGC):
+    """
+    >>> create_obj(ExtTypeNoGC)
+    >>> create_obj(ExtTypeNoGC)
+    >>> create_obj(ExtTypeNoGC)
+
+    >>> class PyExtTypeNoGC(ExtTypeNoGC): pass
+    >>> create_obj(PyExtTypeNoGC)
+    >>> create_obj(PyExtTypeNoGC)
+    >>> create_obj(PyExtTypeNoGC)
+    """
+    cdef int x