rebase: mark --update-refs as requiring the merge backend

--update-refs is built in terms of the sequencer, which requires the
merge backend.  It was already marked as incompatible with the apply
backend in the git-rebase manual, but the code didn't check for this
incompatibility and warn the user.  Check and error now.

While at it, fix a typo in t3422...and fix some misleading wording
(most options which used to be am-specific have since been implemented
in the merge backend as well).

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
index 6dabb05a2a..9da39cd91c 100755
--- a/t/t3422-rebase-incompatible-options.sh
+++ b/t/t3422-rebase-incompatible-options.sh
@@ -25,11 +25,11 @@ test_expect_success 'setup' '
 '
 
 #
-# Rebase has lots of useful options like --whitepsace=fix, which are
-# actually all built in terms of flags to git-am.  Since neither
-# --merge nor --interactive (nor any options that imply those two) use
-# git-am, using them together will result in flags like --whitespace=fix
-# being ignored.  Make sure rebase warns the user and aborts instead.
+# Rebase has a couple options which are specific to the apply backend,
+# and several options which are specific to the merge backend.  Flags
+# from the different sets cannot work together, and we do not want to
+# just ignore one of the sets of flags.  Make sure rebase warns the
+# user and aborts instead.
 #
 
 test_rebase_am_only () {
@@ -60,6 +60,11 @@ test_rebase_am_only () {
 		test_must_fail git rebase $opt --exec 'true' A
 	"
 
+	test_expect_success "$opt incompatible with --update-refs" "
+		git checkout B^0 &&
+		test_must_fail git rebase $opt --update-refs A
+	"
+
 }
 
 test_rebase_am_only --whitespace=fix