#!/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
}

PREV_HEAD_DESC='Previous HEAD position was'
check_orphan_warning() {
        test_i18ngrep "you are leaving $2 behind" "$1" &&
        test_i18ngrep ! "$PREV_HEAD_DESC" "$1"
}
check_no_orphan_warning() {
        test_i18ngrep ! "you are leaving .* commit.*behind" "$1" &&
        test_i18ngrep "$PREV_HEAD_DESC" "$1"
}

reset () {
        git checkout master &&
        check_not_detached
}

test_expect_success 'setup' '
        test_commit one &&
        test_commit two &&
        test_commit three && git tag -d three &&
        test_commit four && git tag -d four &&
        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_expect_success 'checkout warns on orphan commits' '
        reset &&
        git checkout --detach two &&
        echo content >orphan &&
        git add orphan &&
        git commit -a -m orphan1 &&
        echo new content >orphan &&
        git commit -a -m orphan2 &&
        orphan2=$(git rev-parse HEAD) &&
        git checkout master 2>stderr
'

test_expect_success 'checkout warns on orphan commits: output' '
        check_orphan_warning stderr "2 commits"
'

test_expect_success 'checkout warns orphaning 1 of 2 commits' '
        git checkout "$orphan2" &&
        git checkout HEAD^ 2>stderr
'

test_expect_success 'checkout warns orphaning 1 of 2 commits: output' '
        check_orphan_warning stderr "1 commit"
'

test_expect_success 'checkout does not warn leaving ref tip' '
        reset &&
        git checkout --detach two &&
        git checkout master 2>stderr
'

test_expect_success 'checkout does not warn leaving ref tip' '
        check_no_orphan_warning stderr
'

test_expect_success 'checkout does not warn leaving reachable commit' '
        reset &&
        git checkout --detach HEAD^ &&
        git checkout master 2>stderr
'

test_expect_success 'checkout does not warn leaving reachable commit' '
        check_no_orphan_warning stderr
'

cat >expect <<'EOF'
Your branch is behind 'master' by 1 commit, and can be fast-forwarded.
  (use "git pull" to update your local branch)
EOF
test_expect_success 'tracking count is accurate after orphan check' '
        reset &&
        git branch child master^ &&
        git config branch.child.remote . &&
        git config branch.child.merge refs/heads/master &&
        git checkout child^ &&
        git checkout child >stdout &&
        test_i18ncmp expect stdout
'

test_expect_success 'no advice given for explicit detached head state' '
        # baseline
        test_config advice.detachedHead true &&
        git checkout child && git checkout HEAD^0 >expect.advice 2>&1 &&
        test_config advice.detachedHead false &&
        git checkout child && git checkout HEAD^0 >expect.no-advice 2>&1 &&
        test_unconfig advice.detachedHead &&
        # without configuration, the advice.* variables default to true
        git checkout child && git checkout HEAD^0 >actual 2>&1 &&
        test_cmp expect.advice actual &&

        # with explicit --detach
        # no configuration
        test_unconfig advice.detachedHead &&
        git checkout child && git checkout --detach HEAD^0 >actual 2>&1 &&
        test_cmp expect.no-advice actual &&

        # explicitly decline advice
        test_config advice.detachedHead false &&
        git checkout child && git checkout --detach HEAD^0 >actual 2>&1 &&
        test_cmp expect.no-advice actual
'

test_done