merge: always roll back lock in `checkout_fast_forward()`

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.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Martin Ågren committed Feb 28, 2018 at 20:07 UTC 5790d25881a60a1c3a780e997a59774e48c2c026
1 file changed +9 -3
merge.c
+9 -3
@@ -113,17 +113,23 @@ int checkout_fast_forward(const struct object_id *head,
113 setup_unpack_trees_porcelain(&opts, "merge");
114
115 trees[nr_trees] = parse_tree_indirect(head);
116 - if (!trees[nr_trees++])
116 + if (!trees[nr_trees++]) {
117 + rollback_lock_file(&lock_file);
118 return -1;
119 + }
120 trees[nr_trees] = parse_tree_indirect(remote);
119 - if (!trees[nr_trees++])
121 + if (!trees[nr_trees++]) {
122 + rollback_lock_file(&lock_file);
123 return -1;
124 + }
125 for (i = 0; i < nr_trees; i++) {
126 parse_tree(trees[i]);
127 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
128 }
125 - if (unpack_trees(nr_trees, t, &opts))
129 + if (unpack_trees(nr_trees, t, &opts)) {
130 + rollback_lock_file(&lock_file);
131 return -1;
132 + }
133 if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
134 return error(_("unable to write new index file"));
135 return 0;