Fix missing decrements of the recursive counter in PyObject_Compare().

Closes Patch #101065.

diff --git a/Objects/object.c b/Objects/object.c
index a7df5260724c620530165b215e5eb20ab4effc6e..a62c4481ed799ea276405d2c0515c3597a095dcf 100644 (file)
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -403,11 +403,13 @@ PyObject_Compare(PyObject *v, PyObject *w)
                int c;
                if (!PyInstance_Check(v))
                        return -PyObject_Compare(w, v);
-               if (++_PyCompareState_nesting > NESTING_LIMIT) {
+               _PyCompareState_nesting++;
+               if (_PyCompareState_nesting > NESTING_LIMIT) {
                        PyObject *inprogress, *pair;
 
                        inprogress = get_inprogress_dict();
                        if (inprogress == NULL) {
+                               _PyCompareState_nesting--;
                                return -1;
                        }
                        pair = make_pair(v, w);
@@ -415,20 +417,21 @@ PyObject_Compare(PyObject *v, PyObject *w)
                                /* already comparing these objects.  assume
                                   they're equal until shown otherwise */
                                Py_DECREF(pair);
-                               --_PyCompareState_nesting;
+                               _PyCompareState_nesting--;
                                return 0;
                        }
                        if (PyDict_SetItem(inprogress, pair, pair) == -1) {
+                               _PyCompareState_nesting--;
                                return -1;
                        }
                        res = do_cmp(v, w);
-                       _PyCompareState_nesting--;
                        /* XXX DelItem shouldn't fail */
                        PyDict_DelItem(inprogress, pair);
                        Py_DECREF(pair);
                } else {
                        res = do_cmp(v, w);
                }
+               _PyCompareState_nesting--;
                if (res == NULL)
                        return -1;
                if (!PyInt_Check(res)) {
@@ -486,33 +489,36 @@ PyObject_Compare(PyObject *v, PyObject *w)
        if (vtp->tp_compare == NULL) {
                return (v < w) ? -1 : 1;
        }
-       if (++_PyCompareState_nesting > NESTING_LIMIT
+       _PyCompareState_nesting++;
+       if (_PyCompareState_nesting > NESTING_LIMIT
            && (vtp->tp_as_mapping 
                || (vtp->tp_as_sequence && !PyString_Check(v)))) {
                PyObject *inprogress, *pair;
 
                inprogress = get_inprogress_dict();
                if (inprogress == NULL) {
+                       _PyCompareState_nesting--;
                        return -1;
                }
                pair = make_pair(v, w);
                if (PyDict_GetItem(inprogress, pair)) {
                        /* already comparing these objects.  assume
                           they're equal until shown otherwise */
-                       _PyCompareState_nesting--;
                        Py_DECREF(pair);
+                       _PyCompareState_nesting--;
                        return 0;
                }
                if (PyDict_SetItem(inprogress, pair, pair) == -1) {
+                       _PyCompareState_nesting--;
                        return -1;
                }
                result = (*vtp->tp_compare)(v, w);
-               _PyCompareState_nesting--;
                PyDict_DelItem(inprogress, pair); /* XXX shouldn't fail */
                Py_DECREF(pair);
        } else {
                result = (*vtp->tp_compare)(v, w);
        }
+       _PyCompareState_nesting--;
        return result;
 }