Teach rebase the --no-ff option.

For git-rebase.sh, --no-ff is a synonym for --force-rebase.

For git-rebase--interactive.sh, --no-ff cherry-picks all the commits in
the rebased branch, instead of fast-forwarding over any unchanged commits.

--no-ff offers an alternative way to deal with reverted merges.  Instead of
"reverting the revert" you can use "rebase --no-ff" to recreate the branch
with entirely new commits (they're new because at the very least the
committer time is different).  This obviates the need to revert the
reversion, as you can re-merge the new topic branch directly.  Added an
addendum to revert-a-faulty-merge.txt describing the situation and how to
use --no-ff to handle it.

Signed-off-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 32 insertions, 4 deletions

diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 4e35137..624e78e 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -22,12 +22,18 @@ set_fake_editor
 # | \
 # |   F - G - H                (branch1)
 # |     \
-#  \      I                    (branch2)
-#   \
-#     J - K - L - M            (no-conflict-branch)
+# |\      I                    (branch2)
+# | \
+# |   J - K - L - M            (no-conflict-branch)
+#  \
+#    N - O - P                 (no-ff-branch)
 #
 # where A, B, D and G all touch file1, and one, two, three, four all
 # touch file "conflict".
+#
+# WARNING: Modifications to the initial repository can change the SHA ID used
+# in the expect2 file for the 'stop on conflicting pick' test.
+
 
 test_expect_success 'setup' '
 	test_commit A file1 &&
@@ -50,6 +56,11 @@ test_expect_success 'setup' '
 	for n in J K L M
 	do
 		test_commit $n file$n
+	done &&
+	git checkout -b no-ff-branch A &&
+	for n in N O P
+	do
+		test_commit $n file$n
 	done
 '
 
@@ -113,7 +124,7 @@ cat > expect2 << EOF
 D
 =======
 G
->>>>>>> 51047de... G
+>>>>>>> 5d18e54... G
 EOF
 
 test_expect_success 'stop on conflicting pick' '
@@ -553,4 +564,21 @@ test_expect_success 'reword' '
 	git show HEAD~2 | grep "C changed"
 '
 
+test_tick # Ensure that the rebased commits get a different timestamp.
+test_expect_success 'always cherry-pick with --no-ff' '
+	git checkout no-ff-branch &&
+	git tag original-no-ff-branch &&
+	git rebase -i --no-ff A &&
+	touch empty &&
+	for p in 0 1 2
+	do
+		test ! $(git rev-parse HEAD~$p) = $(git rev-parse original-no-ff-branch~$p) &&
+		git diff HEAD~$p original-no-ff-branch~$p > out &&
+		test_cmp empty out
+	done &&
+	test $(git rev-parse HEAD~3) = $(git rev-parse original-no-ff-branch~3) &&
+	git diff HEAD~3 original-no-ff-branch~3 > out &&
+	test_cmp empty out
+'
+
 test_done