Resurrect git-revert.sh example and add comment to builtin-revert.c

I had to scratch my head for quite some time figuring out why we
cannot optimize out write_tree() we do when --no-commit option
is given, whose purpose seem to be only to check if the index is
unmerged, with a simple loop over the active_cache[].

So add a comment to describe why the write_tree() is there, and
resurrect the last scripted version as a reference material in
contrib/example directory with others.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-revert.c b/builtin-revert.c
index 62ab1fa1f484a113f45da96de8cd209a0c5c522e..afc28845f211a8a575baee00f73354ce91ea5a8d 100644 (file)
--- a/builtin-revert.c
+++ b/builtin-revert.c
@@ -246,7 +246,9 @@ static int revert_or_cherry_pick(int argc, const char **argv)
        if (no_commit) {
                /*
                 * We do not intend to commit immediately.  We just want to
-                * merge the differences in.
+                * merge the differences in, so let's compute the tree
+                * that represents the "current" state for merge-recursive
+                * to work on.
                 */
                if (write_tree(head, 0, NULL))
                        die ("Your index file is unmerged.");