[PATCH 1/2] rebase: test broken behavior with --keep-empty

[Patrick Steinhardt <ps@pks.im>]

When a commit is already present in the branch that is being
rebased upon we get an empty commit. Usually we just drop this
commit, but with `--keep-empty` we want to preserve the commit's
message.

Instead of simply applying the empty commit, though, we
erroneously end up in cherry-picking mode without any ability to
get back to the previous rebase.

The same error happens when we try to rebase a commit with
`--keep-empty` that causes a conflict.

Add tests that document this breakage.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 t/t3400-rebase.sh | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh
index 47b5682..6cca319 100755
--- a/t/t3400-rebase.sh
+++ b/t/t3400-rebase.sh
@@ -255,4 +255,30 @@ test_expect_success 'rebase commit with an ancient timestamp' '
 	grep "author .* 34567 +0600$" actual
 '
 
+test_expect_failure 'rebase duplicated commit with --keep-empty' '
+	git reset --hard &&
+	git checkout master &&
+
+	>x && git add x && git commit x -mx &&
+	echo x > x && git commit x -mx1 &&
+
+	git checkout -b duplicated HEAD~ &&
+	echo x > x && git commit x -mx2 &&
+	git rebase --keep-empty master
+'
+
+test_expect_failure 'rebase conflicting commit with --keep-empty' '
+	git reset --hard &&
+	git checkout master &&
+
+	echo y > x && git commit x -my &&
+
+	git checkout -b conflict HEAD~ &&
+	echo z > x && git commit x -mz &&
+	test_must_fail git rebase --keep-empty master &&
+
+	git add x &&
+	git rebase --continue
+'
+
 test_done
-- 
2.6.3