#!/bin/sh

test_description='checkout into detached HEAD state'
. ./test-lib.sh

check_detached () {
        test_must_fail git symbolic-ref -q HEAD >/dev/null
}

check_not_detached () {
        git symbolic-ref -q HEAD >/dev/null
}

reset () {
        git checkout master &&
        check_not_detached
}

test_expect_success 'setup' '
        test_commit one &&
        test_commit two &&
        git branch branch &&
        git tag tag
'

test_expect_success 'checkout branch does not detach' '
        reset &&
        git checkout branch &&
        check_not_detached
'

test_expect_success 'checkout tag detaches' '
        reset &&
        git checkout tag &&
        check_detached
'

test_expect_success 'checkout branch by full name detaches' '
        reset &&
        git checkout refs/heads/branch &&
        check_detached
'

test_expect_success 'checkout non-ref detaches' '
        reset &&
        git checkout branch^ &&
        check_detached
'

test_expect_success 'checkout ref^0 detaches' '
        reset &&
        git checkout branch^0 &&
        check_detached
'

test_expect_success 'checkout --detach detaches' '
        reset &&
        git checkout --detach branch &&
        check_detached
'

test_expect_success 'checkout --detach without branch name' '
        reset &&
        git checkout --detach &&
        check_detached
'

test_expect_success 'checkout --detach errors out for non-commit' '
        reset &&
        test_must_fail git checkout --detach one^{tree} &&
        check_not_detached
'

test_expect_success 'checkout --detach errors out for extra argument' '
        reset &&
        git checkout master &&
        test_must_fail git checkout --detach tag one.t &&
        check_not_detached
'

test_expect_success 'checkout --detached and -b are incompatible' '
        reset &&
        test_must_fail git checkout --detach -b newbranch tag &&
        check_not_detached
'

test_expect_success 'checkout --detach moves HEAD' '
        reset &&
        git checkout one &&
        git checkout --detach two &&
        git diff --exit-code HEAD &&
        git diff --exit-code two
'

test_done