reset: give better reflog messages

The reset command creates its reflog entry from argv.
However, it does so after having run parse_options, which
means the only thing left in argv is any non-option
arguments. Thus you would end up with confusing reflog
entries like:

  $ git reset --hard HEAD^
  $ git reset --soft HEAD@{1}
  $ git log -2 -g --oneline
  8e46cad HEAD@{0}: HEAD@{1}: updating HEAD
  1eb9486 HEAD@{1}: HEAD^: updating HEAD

However, we must also consider that some scripts may set
GIT_REFLOG_ACTION before calling reset, and we need to show
their reflog action (with our text appended). For example:

  rebase -i (squash): updating HEAD

On top of that, we also set the ORIG_HEAD reflog action
(even though it doesn't generally exist). In that case, the
reset argument is somewhat meaningless, as it has nothing to
do with what's in ORIG_HEAD.

This patch changes the reset reflog code to show:

  $GIT_REFLOG_ACTION: updating {HEAD,ORIG_HEAD}

as before, but only if GIT_REFLOG_ACTION is set. Otherwise,
show:

   reset: moving to $rev

for HEAD, and:

   reset: updating ORIG_HEAD

for ORIG_HEAD (this is still somewhat superfluous, since we
are in the ORIG_HEAD reflog, obviously, but at least we now
mention which command was used to update it).

While we're at it, we can clean up the code a bit:

 - Use strbufs to make the message.

 - Use the "rev" parameter instead of showing all options.
   This makes more sense, since it is the only thing
   impacting the writing of the ref.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/t/t1412-reflog-loop.sh b/t/t1412-reflog-loop.sh
index 7f519e5ebe..647d888507 100755
--- a/t/t1412-reflog-loop.sh
+++ b/t/t1412-reflog-loop.sh
@@ -21,10 +21,10 @@ test_expect_success 'setup reflog with alternating commits' '
 
 test_expect_success 'reflog shows all entries' '
 	cat >expect <<-\EOF
-		topic@{0} two: updating HEAD
-		topic@{1} one: updating HEAD
-		topic@{2} two: updating HEAD
-		topic@{3} one: updating HEAD
+		topic@{0} reset: moving to two
+		topic@{1} reset: moving to one
+		topic@{2} reset: moving to two
+		topic@{3} reset: moving to one
 		topic@{4} branch: Created from HEAD
 	EOF
 	git log -g --format="%gd %gs" topic >actual &&