[PATCH 1/3] unpack-trees: simplify 'all other failures' case

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Aug 12, 2014, 23:59 UTC
Message-ID: <20140812235931.GE24621@google.com>
In-Reply-To: <20140812235731.GD24621@google.com>

From: Stefan Beller <stefanbeller@gmail.com>

In the 'if (current)' block of twoway_merge, we handle the boring errors by checking if the entry from the old tree, current index, and new tree are present, to get a pathname for the error message from one of them:

	if (oldtree)
		return o->gently ? -1 : reject_merge(oldtree, o);
	if (current)
		return o->gently ? -1 : reject_merge(current, o);
	if (newtree)
		return o->gently ? -1 : reject_merge(newtree, o);
	return -1;

Since this is guarded by 'if (current)', the second test is guaranteed to succeed. Moreover, any of the three entries, if present, would have the same path because there is no rename detection in this code path. Even if some day in the future the entries' paths differ, the 'current' path used in the index and worktree would presumably be the most recognizable for the end user.

Simplify by just using 'current'.

Noticed by coverity, Id:290002

Signed-off-by: Stefan Beller <stefanbeller@gmail.com>
Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 unpack-trees.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/unpack-trees.c b/unpack-trees.c
index ad3e9a0..f4a9aa9 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1791,16 +1791,8 @@ int twoway_merge(const struct cache_entry * const *src,
 			/* 20 or 21 */
 			return merged_entry(newtree, current, o);
 		}
-		else {
-			/* all other failures */
-			if (oldtree)
-				return o->gently ? -1 : reject_merge(oldtree, o);
-			if (current)
-				return o->gently ? -1 : reject_merge(current, o);
-			if (newtree)
-				return o->gently ? -1 : reject_merge(newtree, o);
-			return -1;
-		}
+		else
+			return o->gently ? -1 : reject_merge(current, o);
 	}
 	else if (newtree) {
 		if (oldtree && !o->initial_checkout) {