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

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/t/t5618-alternate-refs.sh

@@ -0,0 +1,60 @@
+#!/bin/sh
+
+test_description='test handling of --alternate-refs traversal'
+. ./test-lib.sh
+
+# Avoid test_commit because we want a specific and known set of refs:
+#
+#  base -- one
+#      \      \
+#       two -- merged
+#
+# where "one" and "two" are on separate refs, and "merged" is available only in
+# the dependent child repository.
+test_expect_success 'set up local refs' '
+	git checkout -b one &&
+	test_tick &&
+	git commit --allow-empty -m base &&
+	test_tick &&
+	git commit --allow-empty -m one &&
+	git checkout -b two HEAD^ &&
+	test_tick &&
+	git commit --allow-empty -m two
+'
+
+# We'll enter the child repository after it's set up since that's where
+# all of the subsequent tests will want to run (and it's easy to forget a
+# "-C child" and get nonsense results).
+test_expect_success 'set up shared clone' '
+	git clone -s . child &&
+	cd child &&
+	git merge origin/one
+'
+
+test_expect_success 'rev-list --alternate-refs' '
+	git rev-list --remotes=origin >expect &&
+	git rev-list --alternate-refs >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'rev-list --not --alternate-refs' '
+	git rev-parse HEAD >expect &&
+	git rev-list HEAD --not --alternate-refs >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'limiting with alternateRefsPrefixes' '
+	test_config core.alternateRefsPrefixes refs/heads/one &&
+	git rev-list origin/one >expect &&
+	git rev-list --alternate-refs >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'log --source shows .alternate marker' '
+	git log --oneline --source --remotes=origin >expect.orig &&
+	sed "s/origin.* /.alternate /" <expect.orig >expect &&
+	git log --oneline --source --alternate-refs >actual &&
+	test_cmp expect actual
+'
+
+test_done