1 files changed, 288 insertions, 0 deletions
diff --git a/t/t2018-checkout-branch.sh b/t/t2018-checkout-branch.sh
new file mode 100755
index 0000000..771c3c3
--- /dev/null
+++ b/t/t2018-checkout-branch.sh
@@ -0,0 +1,288 @@
+#!/bin/sh
+
+test_description='checkout'
+
+TEST_CREATE_REPO_NO_TEMPLATE=1
+. ./test-lib.sh
+
+# Arguments: [!] <branch> <oid> [<checkout options>]
+#
+# Runs "git checkout" to switch to <branch>, testing that
+#
+#   1) we are on the specified branch, <branch>;
+#   2) HEAD is <oid>; if <oid> is not specified, the old HEAD is used.
+#
+# If <checkout options> is not specified, "git checkout" is run with -b.
+#
+# If the first argument is `!`, "git checkout" is expected to fail when
+# it is run.
+do_checkout () {
+	should_fail= &&
+	if test "x$1" = "x!"
+	then
+		should_fail=yes &&
+		shift
+	fi &&
+	exp_branch=$1 &&
+	exp_ref="refs/heads/$exp_branch" &&
+
+	# if <oid> is not specified, use HEAD.
+	exp_oid=${2:-$(git rev-parse --verify HEAD)} &&
+
+	# default options for git checkout: -b
+	if test -z "$3"
+	then
+		opts="-b"
+	else
+		opts="$3"
+	fi
+
+	if test -n "$should_fail"
+	then
+		test_must_fail git checkout $opts $exp_branch $exp_oid
+	else
+		git checkout $opts $exp_branch $exp_oid &&
+		echo "$exp_ref" >ref.expect &&
+		git rev-parse --symbolic-full-name HEAD >ref.actual &&
+		test_cmp ref.expect ref.actual &&
+		echo "$exp_oid" >oid.expect &&
+		git rev-parse --verify HEAD >oid.actual &&
+		test_cmp oid.expect oid.actual
+	fi
+}
+
+test_dirty_unmergeable () {
+	test_expect_code 1 git diff --exit-code
+}
+
+test_dirty_unmergeable_discards_changes () {
+	git diff --exit-code
+}
+
+setup_dirty_unmergeable () {
+	echo >>file1 change2
+}
+
+test_dirty_mergeable () {
+	test_expect_code 1 git diff --cached --exit-code
+}
+
+test_dirty_mergeable_discards_changes () {
+	git diff --cached --exit-code
+}
+
+setup_dirty_mergeable () {
+	echo >file2 file2 &&
+	git add file2
+}
+
+test_expect_success 'setup' '
+	test_commit initial file1 &&
+	HEAD1=$(git rev-parse --verify HEAD) &&
+
+	test_commit change1 file1 &&
+	HEAD2=$(git rev-parse --verify HEAD) &&
+
+	git branch -m branch1
+'
+
+test_expect_success 'checkout a branch without refs/heads/* prefix' '
+	git clone --no-tags . repo-odd-prefix &&
+	(
+		cd repo-odd-prefix &&
+
+		origin=$(git symbolic-ref refs/remotes/origin/HEAD) &&
+		git symbolic-ref refs/heads/a-branch "$origin" &&
+
+		git checkout -f a-branch &&
+		git checkout -f a-branch
+	)
+'
+
+test_expect_success 'checkout -b to a new branch, set to HEAD' '
+	test_when_finished "
+		git checkout branch1 &&
+		test_might_fail git branch -D branch2" &&
+	do_checkout branch2
+'
+
+test_expect_success 'checkout -b to a merge base' '
+	test_when_finished "
+		git checkout branch1 &&
+		test_might_fail git branch -D branch2" &&
+	git checkout -b branch2 branch1...
+'
+
+test_expect_success 'checkout -b to a new branch, set to an explicit ref' '
+	test_when_finished "
+		git checkout branch1 &&
+		test_might_fail git branch -D branch2" &&
+	do_checkout branch2 $HEAD1
+'
+
+test_expect_success 'checkout -b to a new branch with unmergeable changes fails' '
+	setup_dirty_unmergeable &&
+	do_checkout ! branch2 $HEAD1 &&
+	test_dirty_unmergeable
+'
+
+test_expect_success 'checkout -f -b to a new branch with unmergeable changes discards changes' '
+	test_when_finished "
+		git checkout branch1 &&
+		test_might_fail git branch -D branch2" &&
+
+	# still dirty and on branch1
+	do_checkout branch2 $HEAD1 "-f -b" &&
+	test_dirty_unmergeable_discards_changes
+'
+
+test_expect_success 'checkout -b to a new branch preserves mergeable changes' '
+	test_when_finished "
+		git reset --hard &&
+		git checkout branch1 &&
+		test_might_fail git branch -D branch2" &&
+
+	setup_dirty_mergeable &&
+	do_checkout branch2 $HEAD1 &&
+	test_dirty_mergeable
+'
+
+test_expect_success 'checkout -f -b to a new branch with mergeable changes discards changes' '
+	test_when_finished git reset --hard HEAD &&
+	setup_dirty_mergeable &&
+	do_checkout branch2 $HEAD1 "-f -b" &&
+	test_dirty_mergeable_discards_changes
+'
+
+test_expect_success 'checkout -b to an existing branch fails' '
+	test_when_finished git reset --hard HEAD &&
+	do_checkout ! branch2 $HEAD2
+'
+
+test_expect_success 'checkout -b to @{-1} fails with the right branch name' '
+	git checkout branch1 &&
+	git checkout branch2 &&
+	echo  >expect "fatal: a branch named '\''branch1'\'' already exists" &&
+	test_must_fail git checkout -b @{-1} 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'checkout -B to an existing branch resets branch to HEAD' '
+	git checkout branch1 &&
+
+	do_checkout branch2 "" -B
+'
+
+test_expect_success 'checkout -B to a merge base' '
+	git checkout branch1 &&
+
+	git checkout -B branch2 branch1...
+'
+
+test_expect_success 'checkout -B to an existing branch from detached HEAD resets branch to HEAD' '
+	head=$(git rev-parse --verify HEAD) &&
+	git checkout "$head" &&
+
+	do_checkout branch2 "" -B
+'
+
+test_expect_success 'checkout -B to an existing branch with an explicit ref resets branch to that ref' '
+	git checkout branch1 &&
+
+	do_checkout branch2 $HEAD1 -B
+'
+
+test_expect_success 'checkout -B to an existing branch with unmergeable changes fails' '
+	git checkout branch1 &&
+
+	setup_dirty_unmergeable &&
+	do_checkout ! branch2 $HEAD1 -B &&
+	test_dirty_unmergeable
+'
+
+test_expect_success 'checkout -f -B to an existing branch with unmergeable changes discards changes' '
+	# still dirty and on branch1
+	do_checkout branch2 $HEAD1 "-f -B" &&
+	test_dirty_unmergeable_discards_changes
+'
+
+test_expect_success 'checkout -B to an existing branch preserves mergeable changes' '
+	test_when_finished git reset --hard &&
+	git checkout branch1 &&
+
+	setup_dirty_mergeable &&
+	do_checkout branch2 $HEAD1 -B &&
+	test_dirty_mergeable
+'
+
+test_expect_success 'checkout -f -B to an existing branch with mergeable changes discards changes' '
+	git checkout branch1 &&
+
+	setup_dirty_mergeable &&
+	do_checkout branch2 $HEAD1 "-f -B" &&
+	test_dirty_mergeable_discards_changes
+'
+
+test_expect_success 'checkout -b <describe>' '
+	git tag -f -m "First commit" initial initial &&
+	git checkout -f change1 &&
+	name=$(git describe) &&
+	git checkout -b $name &&
+	git diff --exit-code change1 &&
+	echo "refs/heads/$name" >expect &&
+	git symbolic-ref HEAD >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'checkout -B to the current branch works' '
+	git checkout branch1 &&
+	git checkout -B branch1-scratch &&
+
+	setup_dirty_mergeable &&
+	git checkout -B branch1-scratch initial &&
+	test_dirty_mergeable
+'
+
+test_expect_success 'checkout -b after clone --no-checkout does a checkout of HEAD' '
+	git init src &&
+	test_commit -C src a &&
+	rev="$(git -C src rev-parse HEAD)" &&
+	git clone --no-checkout src dest &&
+	git -C dest checkout "$rev" -b branch &&
+	test_path_is_file dest/a.t
+'
+
+test_expect_success 'checkout -b to a new branch preserves mergeable changes despite sparse-checkout' '
+	test_when_finished "
+		git reset --hard &&
+		git checkout branch1-scratch &&
+		test_might_fail git branch -D branch3 &&
+		git config core.sparseCheckout false &&
+		rm -rf .git/info" &&
+
+	test_commit file2 &&
+
+	echo stuff >>file1 &&
+	mkdir .git/info &&
+	echo file2 >.git/info/sparse-checkout &&
+	git config core.sparseCheckout true &&
+
+	CURHEAD=$(git rev-parse HEAD) &&
+	do_checkout branch3 $CURHEAD &&
+
+	echo file1 >expect &&
+	git diff --name-only >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'checkout -b rejects an invalid start point' '
+	test_must_fail git checkout -b branch4 file1 2>err &&
+	test_i18ngrep "is not a commit" err
+'
+
+test_expect_success 'checkout -b rejects an extra path argument' '
+	test_must_fail git checkout -b branch5 branch1 file1 2>err &&
+	test_i18ngrep "Cannot update paths and switch to branch" err
+'
+
+test_done