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

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

third_party/git/t/t5307-pack-missing-commit.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='pack should notice missing commit objects'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	for i in 1 2 3 4 5
+	do
+		echo "$i" >"file$i" &&
+		git add "file$i" &&
+		test_tick &&
+		git commit -m "$i" &&
+		git tag "tag$i"
+	done &&
+	obj=$(git rev-parse --verify tag3) &&
+	fanout=$(expr "$obj" : "\(..\)") &&
+	remainder=$(expr "$obj" : "..\(.*\)") &&
+	rm -f ".git/objects/$fanout/$remainder"
+'
+
+test_expect_success 'check corruption' '
+	test_must_fail git fsck
+'
+
+test_expect_success 'rev-list notices corruption (1)' '
+	test_must_fail env GIT_TEST_COMMIT_GRAPH=0 git rev-list HEAD
+'
+
+test_expect_success 'rev-list notices corruption (2)' '
+	test_must_fail env GIT_TEST_COMMIT_GRAPH=0 git rev-list --objects HEAD
+'
+
+test_expect_success 'pack-objects notices corruption' '
+	echo HEAD |
+	test_must_fail git pack-objects --revs pack
+'
+
+test_done