Add return value to 'traverse_tree()' callback

This allows the callback to return an error value, but it can also
specify which of the tree entries that it actually used up by returning
a positive mask value.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/merge-tree.c b/merge-tree.c
index a3511b76ca..8be0b9f910 100644
--- a/merge-tree.c
+++ b/merge-tree.c
@@ -287,31 +287,32 @@ static void unresolved(const struct traverse_info *info, struct name_entry n[3])
  * The successful merge rules are the same as for the three-way merge
  * in git-read-tree.
  */
-static void threeway_callback(int n, unsigned long mask, struct name_entry *entry, struct traverse_info *info)
+static int threeway_callback(int n, unsigned long mask, struct name_entry *entry, struct traverse_info *info)
 {
 	/* Same in both? */
 	if (same_entry(entry+1, entry+2)) {
 		if (entry[0].sha1) {
 			resolve(info, NULL, entry+1);
-			return;
+			return mask;
 		}
 	}
 
 	if (same_entry(entry+0, entry+1)) {
 		if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) {
 			resolve(info, entry+1, entry+2);
-			return;
+			return mask;
 		}
 	}
 
 	if (same_entry(entry+0, entry+2)) {
 		if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) {
 			resolve(info, NULL, entry+1);
-			return;
+			return mask;
 		}
 	}
 
 	unresolved(info, entry);
+	return mask;
 }
 
 static void merge_trees(struct tree_desc t[3], const char *base)