gh-97943: PyFunction_GetAnnotations should return a borrowed reference. (GH-97949)

(cherry picked from commit 6bfb0be)

Co-authored-by: larryhastings <[email protected]>

Author: miss-islington

Misc/NEWS.d/next/Core and Builtins/2022-10-05-17-02-22.gh-issue-97943.LYAWlE.rst

@@ -0,0 +1,2 @@
+Bugfix: :func:`PyFunction_GetAnnotations` should return a borrowed
+reference. It was returning a new reference.

Objects/funcobject.c

@@ -300,7 +300,6 @@ func_get_annotation_dict(PyFunctionObject *op)
         }
         Py_SETREF(op->func_annotations, ann_dict);
     }
-    Py_INCREF(op->func_annotations);
     assert(PyDict_Check(op->func_annotations));
     return op->func_annotations;
 }
@@ -532,7 +531,11 @@ func_get_annotations(PyFunctionObject *op, void *Py_UNUSED(ignored))
         if (op->func_annotations == NULL)
             return NULL;
     }
-    return func_get_annotation_dict(op);
+    PyObject *d = func_get_annotation_dict(op);
+    if (d) {
+        Py_INCREF(d);
+    }
+    return d;
 }
 
 static int