[PATCH v2 4/5] merge: always roll back lock in `checkout_fast_forward()`

[Martin Ågren]

This function originated in builtin/merge.c. It was moved to merge.c in
commit db699a8a1f (Move try_merge_command and checkout_fast_forward to
libgit.a, 2012-10-26), but was used from sequencer.c even before that.

If a problem occurs, the function returns without rolling back the
lockfile. Teach it to do so.

Signed-off-by: Martin Ågren <martin.ag...@gmail.com>
---
 merge.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/merge.c b/merge.c
index 195b578700..f06a4773d4 100644
--- a/merge.c
+++ b/merge.c
@@ -113,17 +113,23 @@ int checkout_fast_forward(const struct object_id *head,
        setup_unpack_trees_porcelain(&opts, "merge");
 
        trees[nr_trees] = parse_tree_indirect(head);
-       if (!trees[nr_trees++])
+       if (!trees[nr_trees++]) {
+               rollback_lock_file(&lock_file);
                return -1;
+       }
        trees[nr_trees] = parse_tree_indirect(remote);
-       if (!trees[nr_trees++])
+       if (!trees[nr_trees++]) {
+               rollback_lock_file(&lock_file);
                return -1;
+       }
        for (i = 0; i < nr_trees; i++) {
                parse_tree(trees[i]);
                init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
        }
-       if (unpack_trees(nr_trees, t, &opts))
+       if (unpack_trees(nr_trees, t, &opts)) {
+               rollback_lock_file(&lock_file);
                return -1;
+       }
        if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
                return error(_("unable to write new index file"));
        return 0;
-- 
2.16.2.246.ga4ee44448f