Re: [PATCH] Don't update unchanged merge entries

Linus Torvalds [off-list ref] writes:

On Sun, 16 Mar 2008, Daniel Barkalow wrote:

quoted

Well, the top part of the comment suggests that this is just an 
optimization (don't bother to write out a file that you know is 
unchanged), when it's actually necessary for correctness (since we don't 
know if the working tree matches the old index).

Ahh, that part. Yeah, maybe we could expand/clarify it. I don't think the 
comment is wrong per se, but yes, I'm sure it could be improved. 

Will squash this in (together with the test updates I sent out earlier).

 unpack-trees.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/unpack-trees.c b/unpack-trees.c
index a72ac03..4b359e0 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c

@@ -602,8 +602,8 @@ static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
 		 * See if we can re-use the old CE directly?
 		 * That way we get the uptodate stat info.
 		 *
-		 * This also removes the UPDATE flag on
-		 * a match.
+		 * This also removes the UPDATE flag on a match; otherwise
+		 * we will end up overwriting local changes in the work tree.
 		 */
 		if (same(old, merge)) {
 			copy_cache_entry(merge, old);