unpack-trees: allow sparse directories

The index_pos_by_traverse_info() currently throws a BUG() when a
directory entry exists exactly in the index. We need to consider that it
is possible to have a directory in a sparse index as long as that entry
is itself marked with the skip-worktree bit.

The 'pos' variable is assigned a negative value if an exact match is not
found. Since a directory name can be an exact match, it is no longer an
error to have a nonnegative 'pos' value.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/unpack-trees.c b/unpack-trees.c
index 4dd99219073a4f664a1ebb2c310932db0bad3d9b..0b888dab2246ee3997ffeabf83afc8ae7fd37be1 100644 (file)
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -746,9 +746,13 @@ static int index_pos_by_traverse_info(struct name_entry *names,
        strbuf_make_traverse_path(&name, info, names->path, names->pathlen);
        strbuf_addch(&name, '/');
        pos = index_name_pos(o->src_index, name.buf, name.len);
-       if (pos >= 0)
-               BUG("This is a directory and should not exist in index");
-       pos = -pos - 1;
+       if (pos >= 0) {
+               if (!o->src_index->sparse_index ||
+                   !(o->src_index->cache[pos]->ce_flags & CE_SKIP_WORKTREE))
+                       BUG("This is a directory and should not exist in index");
+       } else {
+               pos = -pos - 1;
+       }
        if (pos >= o->src_index->cache_nr ||
            !starts_with(o->src_index->cache[pos]->name, name.buf) ||
            (pos > 0 && starts_with(o->src_index->cache[pos-1]->name, name.buf)))