get_tree_entry: map blank requested entry to tree root

This means that
  git show HEAD:
will now return HEAD^{tree}, which is logically consistent with
  git show HEAD:Documentation

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/tree-walk.c b/tree-walk.c
index 22f4550b6ca4d2cb185fc19f6be414a8a0874a60..70f899957e8ce511f0f5a470e8b6927d58d1b63e 100644 (file)
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -199,10 +199,17 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
        int retval;
        void *tree;
        struct tree_desc t;
+       unsigned char root[20];
 
-       tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
+       tree = read_object_with_reference(tree_sha1, tree_type, &t.size, root);
        if (!tree)
                return -1;
+
+       if (name[0] == '\0') {
+               hashcpy(sha1, root);
+               return 0;
+       }
+
        t.buf = tree;
        retval = find_tree_entry(&t, name, sha1, mode);
        free(tree);