Mercurial > vim
diff src/list.c @ 24396:d406858354a6 v8.2.2738
patch 8.2.2738: extending a list with itself can give wrong result
Commit: https://github.com/vim/vim/commit/dcae51facc4d6de1edd62f0242b40972be841103
Author: Bram Moolenaar <Bram@vim.org>
Date: Thu Apr 8 20:10:10 2021 +0200
patch 8.2.2738: extending a list with itself can give wrong result
Problem: Extending a list with itself can give wrong result.
Solution: Remember the item before where the insertion happens and skip to
after the already inserted items. (closes #1112)
| author | Bram Moolenaar <Bram@vim.org> |
|---|---|
| date | Thu, 08 Apr 2021 20:15:03 +0200 |
| parents | e695db9a5465 |
| children | 5c6ccab68d1e |
line wrap: on
line diff
--- a/src/list.c +++ b/src/list.c @@ -894,6 +894,7 @@ list_extend(list_T *l1, list_T *l2, list { listitem_T *item; int todo; + listitem_T *bef_prev; // NULL list is equivalent to an empty list: nothing to do. if (l2 == NULL || l2->lv_len == 0) @@ -903,9 +904,15 @@ list_extend(list_T *l1, list_T *l2, list CHECK_LIST_MATERIALIZE(l1); CHECK_LIST_MATERIALIZE(l2); + // When exending a list with itself, at some point we run into the item + // that was before "bef" and need to skip over the already inserted items + // to "bef". + bef_prev = bef == NULL ? NULL : bef->li_prev; + // We also quit the loop when we have inserted the original item count of // the list, avoid a hang when we extend a list with itself. - for (item = l2->lv_first; item != NULL && --todo >= 0; item = item->li_next) + for (item = l2->lv_first; item != NULL && --todo >= 0; + item = item == bef_prev ? bef : item->li_next) if (list_insert_tv(l1, &item->li_tv, bef) == FAIL) return FAIL; return OK;