get_tree_entry(): do not call find_tree_entry() on an empty tree

We know we will find nothing.

This incidentally squelches false warning from gcc about potentially
uninitialized usage of t.entry fields. For an empty tree, it is true that
init_tree_desc() does not call decode_tree_entry() and the tree_desc is
left uninitialized, but find_tree_entry() only calls tree_entry_extract()
that uses the tree_desc while it has more things to read from the tree, so
the uninitialized t.entry fields are never used in such a case anyway.

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

diff --git a/tree-walk.c b/tree-walk.c
index f5d19f9cc16ec1c94c9b1bf8d14fd3d8620ff871..cc2f14a0d6fd3a115ab453b4f28823400550cf60 100644 (file)
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -465,7 +465,6 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
        int retval;
        void *tree;
        unsigned long size;
-       struct tree_desc t;
        unsigned char root[20];
 
        tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
@@ -478,8 +477,13 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
                return 0;
        }
 
-       init_tree_desc(&t, tree, size);
-       retval = find_tree_entry(&t, name, sha1, mode);
+       if (!size) {
+               retval = -1;
+       } else {
+               struct tree_desc t;
+               init_tree_desc(&t, tree, size);
+               retval = find_tree_entry(&t, name, sha1, mode);
+       }
        free(tree);
        return retval;
 }