bpo-38555: Fix an undefined behavior. (GH-16883)
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 5ac7bb1..d909f22 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3830,22 +3830,21 @@
PyDictKeysObject *k = d->ma_keys;
PyObject *key, *value, *result;
+ if (i < 0) {
+ goto fail;
+ }
if (d->ma_values) {
- if (i < 0) {
- goto fail;
- }
key = DK_ENTRIES(k)[i].me_key;
value = d->ma_values[i];
assert (value != NULL);
}
else {
PyDictKeyEntry *entry_ptr = &DK_ENTRIES(k)[i];
- while (i >= 0 && entry_ptr->me_value == NULL) {
+ while (entry_ptr->me_value == NULL) {
+ if (--i < 0) {
+ goto fail;
+ }
entry_ptr--;
- i--;
- }
- if (i < 0) {
- goto fail;
}
key = entry_ptr->me_key;
value = entry_ptr->me_value;