3 files changed, 96 insertions, 3 deletions

diff --git a/sequencer.c b/sequencer.c
index 0a291c91fe..39363a950f 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -3219,10 +3219,27 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 					intend_to_amend();
 				return error_failed_squash(item->commit, opts,
 					item->arg_len, item->arg);
-			} else if (res && is_rebase_i(opts) && item->commit)
+			} else if (res && is_rebase_i(opts) && item->commit) {
+				int to_amend = 0;
+				struct object_id oid;
+
+				/*
+				 * If we are rewording and have either
+				 * fast-forwarded already, or are about to
+				 * create a new root commit, we want to amend,
+				 * otherwise we do not.
+				 */
+				if (item->command == TODO_REWORD &&
+				    !get_oid("HEAD", &oid) &&
+				    (!oidcmp(&item->commit->object.oid, &oid) ||
+				     (opts->have_squash_onto &&
+				      !oidcmp(&opts->squash_onto, &oid))))
+					to_amend = 1;
+
 				return res | error_with_patch(item->commit,
-					item->arg, item->arg_len, opts, res,
-					item->command == TODO_REWORD);
+						item->arg, item->arg_len, opts,
+						res, to_amend);
+			}
 		} else if (item->command == TODO_EXEC) {
 			char *end_of_arg = (char *)(item->arg + item->arg_len);
 			int saved = *end_of_arg;
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 352a52e59d..d392160ba9 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -981,7 +981,35 @@ test_expect_success 'rebase -i --root reword root commit' '
 	test -z "$(git show -s --format=%p HEAD^)"
 '
 
+test_expect_success 'rebase -i --root when root has untracked file confilct' '
+	test_when_finished "reset_rebase" &&
+	git checkout -b failing-root-pick A &&
+	echo x >file2 &&
+	git rm file1 &&
+	git commit -m "remove file 1 add file 2" &&
+	echo z >file1 &&
+	set_fake_editor &&
+	test_must_fail env FAKE_LINES="1 2" git rebase -i --root &&
+	rm file1 &&
+	git rebase --continue &&
+	test "$(git log -1 --format=%B)" = "remove file 1 add file 2" &&
+	test "$(git rev-list --count HEAD)" = 2
+'
+
+test_expect_success 'rebase -i --root reword root when root has untracked file conflict' '
+	test_when_finished "reset_rebase" &&
+	echo z>file1 &&
+	set_fake_editor &&
+	test_must_fail env FAKE_LINES="reword 1 2" \
+		FAKE_COMMIT_MESSAGE="Modified A" git rebase -i --root &&
+	rm file1 &&
+	FAKE_COMMIT_MESSAGE="Reworded A" git rebase --continue &&
+	test "$(git log -1 --format=%B HEAD^)" = "Reworded A" &&
+	test "$(git rev-list --count HEAD)" = 2
+'
+
 test_expect_success C_LOCALE_OUTPUT 'rebase --edit-todo does not work on non-interactive rebase' '
+	git checkout reword-root-branch &&
 	git reset --hard &&
 	git checkout conflict-branch &&
 	set_fake_editor &&
diff --git a/t/t3423-rebase-reword.sh b/t/t3423-rebase-reword.sh
new file mode 100755
index 0000000000..6963750794
--- /dev/null
+++ b/t/t3423-rebase-reword.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+test_description='git rebase interactive with rewording'
+
+. ./test-lib.sh
+
+. "$TEST_DIRECTORY"/lib-rebase.sh
+
+test_expect_success 'setup' '
+	test_commit master file-1 test &&
+
+	git checkout -b stuff &&
+
+	test_commit feature_a file-2 aaa &&
+	test_commit feature_b file-2 ddd
+'
+
+test_expect_success 'reword without issues functions as intended' '
+	test_when_finished "reset_rebase" &&
+
+	git checkout stuff^0 &&
+
+	set_fake_editor &&
+	FAKE_LINES="pick 1 reword 2" FAKE_COMMIT_MESSAGE="feature_b_reworded" \
+		git rebase -i -v master &&
+
+	test "$(git log -1 --format=%B)" = "feature_b_reworded" &&
+	test $(git rev-list --count HEAD) = 3
+'
+
+test_expect_success 'reword after a conflict preserves commit' '
+	test_when_finished "reset_rebase" &&
+
+	git checkout stuff^0 &&
+
+	set_fake_editor &&
+	test_must_fail env FAKE_LINES="reword 2" \
+		git rebase -i -v master &&
+
+	git checkout --theirs file-2 &&
+	git add file-2 &&
+	FAKE_COMMIT_MESSAGE="feature_b_reworded" git rebase --continue &&
+
+	test "$(git log -1 --format=%B)" = "feature_b_reworded" &&
+	test $(git rev-list --count HEAD) = 2
+'
+
+test_done