Merge branch 'js/fix-merge-arg-quoting-in-rebase-p'

"git rebase -p" mangled log messages of a merge commit, which is
now fixed.

* js/fix-merge-arg-quoting-in-rebase-p:
  rebase -p: fix incorrect commit message when calling `git merge`.

git-rebase--interactive.sh

@@ -396,7 +396,7 @@ pick_one_preserving_merges () {
 					--sq-quote "$gpg_sign_opt")} \
 				$allow_rerere_autoupdate "$merge_args" \
 				"$strategy_args" \
-				-m $(git rev-parse --sq-quote "$msg_content") \
+				-m "$(git rev-parse --sq-quote "$msg_content")" \
 				"$new_parents"
 			then
 				printf "%s\n" "$msg_content" > "$GIT_DIR"/MERGE_MSG

t/t3408-rebase-multi-line.sh

@@ -24,8 +24,23 @@ But otherwise with a sane description." &&
 	>elif &&
 	git add elif &&
 	test_tick &&
-	git commit -m second
+	git commit -m second &&
 
+	git checkout -b side2 &&
+	>afile &&
+	git add afile &&
+	test_tick &&
+	git commit -m third &&
+	echo hello >afile &&
+	test_tick &&
+	git commit -a -m fourth &&
+	git checkout -b side-merge &&
+	git reset --hard HEAD^^ &&
+	git merge --no-ff -m "A merge commit log message that has a long
+summary that spills over multiple lines.
+
+But otherwise with a sane description." side2 &&
+	git branch side-merge-original
 '
 
 test_expect_success rebase '
@@ -36,6 +51,15 @@ test_expect_success rebase '
 	git cat-file commit side@{1} | sed -e "1,/^\$/d" >expect &&
 	test_cmp expect actual
 
+'
+test_expect_success rebasep '
+
+	git checkout side-merge &&
+	git rebase -p side &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	git cat-file commit side-merge-original | sed -e "1,/^\$/d" >expect &&
+	test_cmp expect actual
+
 '
 
 test_done