merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 332 insertions, 0 deletions

diff --git a/third_party/git/t/t2020-checkout-detach.sh b/third_party/git/t/t2020-checkout-detach.sh
new file mode 100755
index 000000000000..b748db9946ef
--- /dev/null
+++ b/third_party/git/t/t2020-checkout-detach.sh
@@ -0,0 +1,332 @@
+#!/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
+'
+
+# Detached HEAD tests for GIT_PRINT_SHA1_ELLIPSIS (new format)
+test_expect_success 'describe_detached_head prints no SHA-1 ellipsis when not asked to' "
+
+	commit=$(git rev-parse --short=12 master^) &&
+	commit2=$(git rev-parse --short=12 master~2) &&
+	commit3=$(git rev-parse --short=12 master~3) &&
+
+	# The first detach operation is more chatty than the following ones.
+	cat >1st_detach <<-EOF &&
+	Note: switching to 'HEAD^'.
+
+	You are in 'detached HEAD' state. You can look around, make experimental
+	changes and commit them, and you can discard any commits you make in this
+	state without impacting any branches by switching back to a branch.
+
+	If you want to create a new branch to retain commits you create, you may
+	do so (now or later) by using -c with the switch command. Example:
+
+	  git switch -c <new-branch-name>
+
+	Or undo this operation with:
+
+	  git switch -
+
+	Turn off this advice by setting config variable advice.detachedHead to false
+
+	HEAD is now at \$commit three
+	EOF
+
+	# The remaining ones just show info about previous and current HEADs.
+	cat >2nd_detach <<-EOF &&
+	Previous HEAD position was \$commit three
+	HEAD is now at \$commit2 two
+	EOF
+
+	cat >3rd_detach <<-EOF &&
+	Previous HEAD position was \$commit2 two
+	HEAD is now at \$commit3 one
+	EOF
+
+	reset &&
+	check_not_detached &&
+
+	# Various ways of *not* asking for ellipses
+
+	sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS="no" git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS= git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual &&
+
+	sane_unset GIT_PRINT_SHA1_ELLIPSIS &&
+
+	# We only have four commits, but we can re-use them
+	reset &&
+	check_not_detached &&
+
+	# Make no mention of the env var at all
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS='nope' &&
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=nein &&
+	git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual &&
+
+	true
+"
+
+# Detached HEAD tests for GIT_PRINT_SHA1_ELLIPSIS (old format)
+test_expect_success 'describe_detached_head does print SHA-1 ellipsis when asked to' "
+
+	commit=$(git rev-parse --short=12 master^) &&
+	commit2=$(git rev-parse --short=12 master~2) &&
+	commit3=$(git rev-parse --short=12 master~3) &&
+
+	# The first detach operation is more chatty than the following ones.
+	cat >1st_detach <<-EOF &&
+	Note: switching to 'HEAD^'.
+
+	You are in 'detached HEAD' state. You can look around, make experimental
+	changes and commit them, and you can discard any commits you make in this
+	state without impacting any branches by switching back to a branch.
+
+	If you want to create a new branch to retain commits you create, you may
+	do so (now or later) by using -c with the switch command. Example:
+
+	  git switch -c <new-branch-name>
+
+	Or undo this operation with:
+
+	  git switch -
+
+	Turn off this advice by setting config variable advice.detachedHead to false
+
+	HEAD is now at \$commit... three
+	EOF
+
+	# The remaining ones just show info about previous and current HEADs.
+	cat >2nd_detach <<-EOF &&
+	Previous HEAD position was \$commit... three
+	HEAD is now at \$commit2... two
+	EOF
+
+	cat >3rd_detach <<-EOF &&
+	Previous HEAD position was \$commit2... two
+	HEAD is now at \$commit3... one
+	EOF
+
+	reset &&
+	check_not_detached &&
+
+	# Various ways of asking for ellipses...
+	# The user can just use any kind of quoting (including none).
+
+	GIT_PRINT_SHA1_ELLIPSIS=yes git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 1st_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=Yes git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 2nd_detach actual &&
+
+	GIT_PRINT_SHA1_ELLIPSIS=YES git -c 'core.abbrev=12' checkout HEAD^ >actual 2>&1 &&
+	check_detached &&
+	test_i18ncmp 3rd_detach actual &&
+
+	true
+"
+
+test_done