trivial: use git-repo-config to detect if the test can be run on the repository

diff --git a/read-tree.c b/read-tree.c
index e3b9c0d9fa1cb5a03d1a3a08f992074293285904..a46c6fe2f5d3234abe5dce0b7a9d44da07b6dae9 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -294,17 +294,20 @@ static int unpack_trees(merge_fn_t fn)
 {
        int indpos = 0;
        unsigned len = object_list_length(trees);
-       struct tree_entry_list **posns = 
-               xmalloc(len * sizeof(struct tree_entry_list *));
+       struct tree_entry_list **posns;
        int i;
        struct object_list *posn = trees;
        merge_size = len;
-       for (i = 0; i < len; i++) {
-               posns[i] = ((struct tree *) posn->item)->entries;
-               posn = posn->next;
+
+       if (len) {
+               posns = xmalloc(len * sizeof(struct tree_entry_list *));
+               for (i = 0; i < len; i++) {
+                       posns[i] = ((struct tree *) posn->item)->entries;
+                       posn = posn->next;
+               }
+               if (unpack_trees_rec(posns, len, "", fn, &indpos))
+                       return -1;
        }
-       if (unpack_trees_rec(posns, len, "", fn, &indpos))
-               return -1;
 
        if (trivial_merges_only && nontrivial_merge)
                die("Merge requires file-level merging");