Show a failure of rebase -p if the merge had a conflict

This extends t3409-rebase-preserve-merges by a case where the merge that
is rebased has a conflict. Therefore, the rebase stops and expects that
the user resolves the conflict. However, currently rebase --continue
fails because .git/rebase-merge/author-script is missing.

The test script had allocated two identical clones, but only one of them
(clone2) was used. Now we use both as indicated in the comment. Also,
two instances of && was missing in the setup part.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3409-rebase-preserve-merges.sh

@@ -11,15 +11,23 @@ Run "git rebase -p" and check that merges are properly carried along
 GIT_AUTHOR_EMAIL=bogus_email_address
 export GIT_AUTHOR_EMAIL
 
-#echo 'Setting up:
+# Clone 1 (trivial merge):
 #
-#A1--A2  <-- origin/master
-# \   \
-#  B1--M  <-- topic
-#   \
-#    B2  <-- origin/topic
+# A1--A2  <-- origin/master
+#  \   \
+#   B1--M  <-- topic
+#    \
+#     B2  <-- origin/topic
 #
-#'
+# Clone 2 (conflicting merge):
+#
+# A1--A2--B3   <-- origin/master
+#  \       \
+#   B1------M  <-- topic
+#    \
+#     B2       <-- origin/topic
+#
+# In both cases, 'topic' is rebased onto 'origin/topic'.
 
 test_expect_success 'setup for merge-preserving rebase' \
 	'echo First > A &&
@@ -37,12 +45,19 @@ test_expect_success 'setup for merge-preserving rebase' \
 	cd clone1 &&
 	git checkout -b topic origin/topic &&
 	git merge origin/master &&
-	cd ..
+	cd .. &&
+
+	echo Fifth > B &&
+	git add B &&
+	git commit -m "Add different B" &&
 
-	git clone ./. clone2
+	git clone ./. clone2 &&
 	cd clone2 &&
 	git checkout -b topic origin/topic &&
-	git merge origin/master &&
+	test_must_fail git merge origin/master &&
+	echo Resolved > B &&
+	git add B &&
+	git commit -m "Merge origin/master into topic" &&
 	cd .. &&
 
 	git checkout topic &&
@@ -51,11 +66,29 @@ test_expect_success 'setup for merge-preserving rebase' \
 '
 
 test_expect_success 'rebase -p fakes interactive rebase' '
-	cd clone2 &&
+	(
+	cd clone1 &&
 	git fetch &&
 	git rebase -p origin/topic &&
 	test 1 = $(git rev-list --all --pretty=oneline | grep "Modify A" | wc -l) &&
 	test 1 = $(git rev-list --all --pretty=oneline | grep "Merge commit" | wc -l)
+	)
+'
+
+test_expect_failure '--continue works after a conflict' '
+	(
+	cd clone2 &&
+	git fetch &&
+	test_must_fail git rebase -p origin/topic &&
+	test 2 = $(git ls-files B | wc -l) &&
+	echo Resolved again > B &&
+	test_must_fail git rebase --continue &&
+	git add B &&
+	git rebase --continue &&
+	test 1 = $(git rev-list --all --pretty=oneline | grep "Modify A" | wc -l) &&
+	test 1 = $(git rev-list --all --pretty=oneline | grep "Add different" | wc -l) &&
+	test 1 = $(git rev-list --all --pretty=oneline | grep "Merge origin" | wc -l)
+	)
 '
 
 test_done