1 files changed, 399 insertions, 0 deletions
diff --git a/t/t3451-history-reword.sh b/t/t3451-history-reword.sh
new file mode 100755
index 0000000000..de7b357685
--- /dev/null
+++ b/t/t3451-history-reword.sh
@@ -0,0 +1,399 @@
+#!/bin/sh
+
+test_description='tests for git-history reword subcommand'
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY/lib-log-graph.sh"
+
+reword_with_message () {
+	cat >message &&
+	write_script fake-editor.sh <<-\EOF &&
+	cp message "$1"
+	EOF
+	test_set_editor "$(pwd)"/fake-editor.sh &&
+	git history reword "$@" &&
+	rm fake-editor.sh message
+}
+
+expect_graph () {
+	cat >expect &&
+	lib_test_cmp_graph --graph --format=%s "$@"
+}
+
+expect_log () {
+	git log --format="%s" "$@" >actual &&
+	cat >expect &&
+	test_cmp expect actual
+}
+
+test_expect_success 'can reword tip of a branch' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+		test_commit second &&
+		test_commit third &&
+
+		git symbolic-ref HEAD >expect &&
+		reword_with_message HEAD <<-EOF &&
+		third reworded
+		EOF
+		git symbolic-ref HEAD >actual &&
+		test_cmp expect actual &&
+
+		expect_log <<-\EOF &&
+		third reworded
+		second
+		first
+		EOF
+
+		git reflog >reflog &&
+		test_grep "reword: updating HEAD" reflog
+	)
+'
+
+test_expect_success 'can reword commit in the middle' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+		test_commit second &&
+		test_commit third &&
+
+		git symbolic-ref HEAD >expect &&
+		reword_with_message HEAD~ <<-EOF &&
+		second reworded
+		EOF
+		git symbolic-ref HEAD >actual &&
+		test_cmp expect actual &&
+
+		expect_log <<-\EOF
+		third
+		second reworded
+		first
+		EOF
+	)
+'
+
+test_expect_success 'can reword commit in the middle even on detached head' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+		test_commit second &&
+		test_commit third_on_main &&
+		git checkout --detach HEAD^ &&
+		test_commit third_on_head &&
+
+		reword_with_message HEAD~ <<-EOF &&
+		second reworded
+		EOF
+
+		expect_graph HEAD --branches <<-\EOF
+		* third_on_head
+		| * third_on_main
+		|/
+		* second reworded
+		* first
+		EOF
+       )
+'
+
+test_expect_success 'can reword the detached head' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+		test_commit second &&
+		git checkout --detach HEAD &&
+		test_commit third &&
+
+		reword_with_message HEAD <<-EOF &&
+		third reworded
+		EOF
+
+		expect_log <<-\EOF
+		third reworded
+		second
+		first
+		EOF
+	)
+'
+
+test_expect_success 'can reword root commit' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+		test_commit second &&
+		test_commit third &&
+		reword_with_message HEAD~2 <<-EOF &&
+		first reworded
+		EOF
+
+		expect_log <<-\EOF
+		third
+		second
+		first reworded
+		EOF
+	)
+'
+
+test_expect_success 'can reword in a bare repo' '
+	test_when_finished "rm -rf repo repo.git" &&
+	git init repo &&
+	test_commit -C repo first &&
+	git clone --bare repo repo.git &&
+	(
+		cd repo.git &&
+		reword_with_message HEAD <<-EOF &&
+		reworded
+		EOF
+
+		expect_log <<-\EOF
+		reworded
+		EOF
+	)
+'
+
+test_expect_success 'can reword a commit on a different branch' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit base &&
+		git branch theirs &&
+		test_commit ours &&
+		git switch theirs &&
+		test_commit theirs &&
+
+		git rev-parse ours >ours-before &&
+		reword_with_message theirs <<-EOF &&
+		Reworded theirs
+		EOF
+		git rev-parse ours >ours-after &&
+		test_cmp ours-before ours-after &&
+
+		expect_graph --branches <<-\EOF
+		* Reworded theirs
+		| * ours
+		|/
+		* base
+		EOF
+	)
+'
+
+test_expect_success 'can reword a merge commit' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit base &&
+		git branch branch &&
+		test_commit ours &&
+		git switch branch &&
+		test_commit theirs &&
+		git switch - &&
+		git merge theirs &&
+
+		# It is not possible to replay merge commits embedded in the
+		# history (yet).
+		test_must_fail git -c core.editor=false history reword HEAD~ 2>err &&
+		test_grep "replaying merge commits is not supported yet" err &&
+
+		# But it is possible to reword a merge commit directly.
+		reword_with_message HEAD <<-EOF &&
+		Reworded merge commit
+		EOF
+		expect_graph <<-\EOF
+		*   Reworded merge commit
+		|\
+		| * theirs
+		* | ours
+		|/
+		* base
+		EOF
+	)
+'
+
+test_expect_success '--dry-run prints ref updates without modifying repo' '
+	test_when_finished "rm -rf repo" &&
+	git init repo --initial-branch=main &&
+	(
+		cd repo &&
+		test_commit base &&
+		git branch branch &&
+		test_commit ours &&
+		git switch branch &&
+		test_commit theirs &&
+
+		git refs list >refs-expect &&
+		reword_with_message --dry-run --update-refs=head base >updates <<-\EOF &&
+		reworded commit
+		EOF
+		git refs list >refs-actual &&
+		test_cmp refs-expect refs-actual &&
+		test_grep "update refs/heads/branch" updates &&
+		test_grep ! "update refs/heads/main" updates &&
+
+		reword_with_message --dry-run base >updates <<-\EOF &&
+		reworded commit
+		EOF
+		git refs list >refs-actual &&
+		test_cmp refs-expect refs-actual &&
+
+		test_grep "update refs/heads/branch" updates &&
+		test_grep "update refs/heads/main" updates &&
+		git update-ref --stdin <updates &&
+		expect_log --branches <<-\EOF
+		theirs
+		ours
+		reworded commit
+		EOF
+	)
+'
+
+test_expect_success '--update-refs=head updates only HEAD' '
+	test_when_finished "rm -rf repo" &&
+	git init repo --initial-branch=main &&
+	(
+		cd repo &&
+		test_commit base &&
+		git branch branch &&
+		test_commit theirs &&
+		git switch branch &&
+		test_commit ours &&
+
+		# When told to update HEAD, only, the command will refuse to
+		# rewrite commits that are not an ancestor of HEAD.
+		test_must_fail git -c core.editor=false history reword --update-refs=head theirs 2>err &&
+		test_grep "rewritten commit must be an ancestor of HEAD" err &&
+
+		reword_with_message --update-refs=head base >updates <<-\EOF &&
+		reworded base
+		EOF
+		expect_log HEAD <<-\EOF &&
+		ours
+		reworded base
+		EOF
+		expect_log main <<-\EOF
+		theirs
+		base
+		EOF
+	)
+'
+
+test_expect_success 'editor shows proper status' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+
+		write_script fake-editor.sh <<-\EOF &&
+		cp "$1" . &&
+		printf "\namend a comment\n" >>"$1"
+		EOF
+		test_set_editor "$(pwd)"/fake-editor.sh &&
+		git history reword HEAD &&
+
+		cat >expect <<-EOF &&
+		first
+
+		# Please enter the commit message for the reworded changes. Lines starting
+		# with ${SQ}#${SQ} will be ignored, and an empty message aborts the commit.
+		# Changes to be committed:
+		#	new file:   first.t
+		#
+		EOF
+		test_cmp expect COMMIT_EDITMSG &&
+
+		test_commit_message HEAD <<-\EOF
+		first
+
+		amend a comment
+		EOF
+	)
+'
+
+# For now, git-history(1) does not yet execute any hooks. This is subject to
+# change in the future, and if it does this test here is expected to start
+# failing. In other words, this test is not an endorsement of the current
+# status quo.
+test_expect_success 'hooks are not executed for rewritten commits' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+		test_commit second &&
+		test_commit third &&
+
+		ORIG_PATH="$(pwd)" &&
+		export ORIG_PATH &&
+		for hook in prepare-commit-msg pre-commit post-commit post-rewrite commit-msg
+		do
+			write_script .git/hooks/$hook <<-\EOF || exit 1
+			touch "$ORIG_PATH/hooks.log
+			EOF
+		done &&
+
+		reword_with_message HEAD~ <<-EOF &&
+		second reworded
+		EOF
+
+		cat >expect <<-EOF &&
+		third
+		second reworded
+		first
+		EOF
+		git log --format=%s >actual &&
+		test_cmp expect actual &&
+
+		test_path_is_missing hooks.log
+	)
+'
+
+test_expect_success 'aborts with empty commit message' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit first &&
+
+		! reword_with_message HEAD 2>err </dev/null &&
+		test_grep "Aborting commit due to empty commit message." err
+	)
+'
+
+test_expect_success 'retains changes in the worktree and index' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		touch a b &&
+		git add . &&
+		git commit -m "initial commit" &&
+		echo foo >a &&
+		echo bar >b &&
+		git add b &&
+		reword_with_message HEAD <<-EOF &&
+		message
+		EOF
+		cat >expect <<-\EOF &&
+		 M a
+		M  b
+		?? actual
+		?? expect
+		EOF
+		git status --porcelain >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_done