diff-index --cached --raw: show tree entry on the LHS for unmerged entries.

This updates the way diffcore represents an unmerged pair
somewhat.  It used to be that entries with mode=0 on both sides
were used to represent an unmerged pair, but now it has an
explicit flag.  This is to allow diff-index --cached to report
the entry from the tree when the path is unmerged in the index.

This is used in updating "git reset <tree> -- <path>" to restore
absense of the path in the index from the tree.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/diff.c b/diff.c
index f14288bb8a..2c2e9dcb8c 100644
--- a/diff.c
+++ b/diff.c
@@ -2875,10 +2875,12 @@ void diff_change(struct diff_options *options,
 }
 
 void diff_unmerge(struct diff_options *options,
-		  const char *path)
+		  const char *path,
+		  unsigned mode, const unsigned char *sha1)
 {
 	struct diff_filespec *one, *two;
 	one = alloc_filespec(path);
 	two = alloc_filespec(path);
-	diff_queue(&diff_queued_diff, one, two);
+	fill_filespec(one, sha1, mode);
+	diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
 }