[PATCH] Fix read-tree merging more than 3 trees using 3-way merge

[Junio C Hamano <gitster@pobox.com>]

For multi-base merges, we allowed read-tree -m to take more than
three trees (the last two are our and their branches, and all the
earlier ones, typically one but potentially more, are used as the
merge base).  Unfortunately, the conversion done by commit 933bf40
broke this.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin-read-tree.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index 1967d10..5b07e9a 100644
--- a/builtin-read-tree.c
+++ b/builtin-read-tree.c
@@ -96,7 +96,7 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 {
 	int i, newfd, stage = 0;
 	unsigned char sha1[20];
-	struct tree_desc t[3];
+	struct tree_desc t[20];
 	struct unpack_trees_options opts;
 
 	memset(&opts, 0, sizeof(opts));
@@ -263,6 +263,9 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 			opts.head_idx = 1;
 	}
 
+	if (ARRAY_SIZE(t) < nr_trees)
+		die("I cannot read more than %d trees", ARRAY_SIZE(t));
+
 	for (i = 0; i < nr_trees; i++) {
 		struct tree *tree = trees[i];
 		parse_tree(tree);
-- 
1.5.3.rc5