8 files changed, 873 insertions, 2 deletions

diff --git a/t/helper/test-drop-caches.c b/t/helper/test-drop-caches.c
index d6bcfddf13..f65e301f9d 100644
--- a/t/helper/test-drop-caches.c
+++ b/t/helper/test-drop-caches.c
@@ -16,8 +16,8 @@ static int cmd_sync(void)
 	if ((0 == dwRet) || (dwRet > MAX_PATH))
 		return error("Error getting current directory");
 
-	if ((Buffer[0] < 'A') || (Buffer[0] > 'Z'))
-		return error("Invalid drive letter '%c'", Buffer[0]);
+	if (!has_dos_drive_prefix(Buffer))
+		return error("'%s': invalid drive letter", Buffer);
 
 	szVolumeAccessPath[4] = Buffer[0];
 	hVolWrite = CreateFile(szVolumeAccessPath, GENERIC_READ | GENERIC_WRITE,
diff --git a/t/helper/test-json-writer.c b/t/helper/test-json-writer.c
new file mode 100644
index 0000000000..37c452535f
--- /dev/null
+++ b/t/helper/test-json-writer.c
@@ -0,0 +1,565 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "json-writer.h"
+
+static const char *expect_obj1 = "{\"a\":\"abc\",\"b\":42,\"c\":true}";
+static const char *expect_obj2 = "{\"a\":-1,\"b\":2147483647,\"c\":0}";
+static const char *expect_obj3 = "{\"a\":0,\"b\":4294967295,\"c\":9223372036854775807}";
+static const char *expect_obj4 = "{\"t\":true,\"f\":false,\"n\":null}";
+static const char *expect_obj5 = "{\"abc\\tdef\":\"abc\\\\def\"}";
+static const char *expect_obj6 = "{\"a\":3.14}";
+
+static const char *pretty_obj1 = ("{\n"
+				  "  \"a\": \"abc\",\n"
+				  "  \"b\": 42,\n"
+				  "  \"c\": true\n"
+				  "}");
+static const char *pretty_obj2 = ("{\n"
+				  "  \"a\": -1,\n"
+				  "  \"b\": 2147483647,\n"
+				  "  \"c\": 0\n"
+				  "}");
+static const char *pretty_obj3 = ("{\n"
+				  "  \"a\": 0,\n"
+				  "  \"b\": 4294967295,\n"
+				  "  \"c\": 9223372036854775807\n"
+				  "}");
+static const char *pretty_obj4 = ("{\n"
+				  "  \"t\": true,\n"
+				  "  \"f\": false,\n"
+				  "  \"n\": null\n"
+				  "}");
+
+static struct json_writer obj1 = JSON_WRITER_INIT;
+static struct json_writer obj2 = JSON_WRITER_INIT;
+static struct json_writer obj3 = JSON_WRITER_INIT;
+static struct json_writer obj4 = JSON_WRITER_INIT;
+static struct json_writer obj5 = JSON_WRITER_INIT;
+static struct json_writer obj6 = JSON_WRITER_INIT;
+
+static void make_obj1(int pretty)
+{
+	jw_object_begin(&obj1, pretty);
+	{
+		jw_object_string(&obj1, "a", "abc");
+		jw_object_intmax(&obj1, "b", 42);
+		jw_object_true(&obj1, "c");
+	}
+	jw_end(&obj1);
+}
+
+static void make_obj2(int pretty)
+{
+	jw_object_begin(&obj2, pretty);
+	{
+		jw_object_intmax(&obj2, "a", -1);
+		jw_object_intmax(&obj2, "b", 0x7fffffff);
+		jw_object_intmax(&obj2, "c", 0);
+	}
+	jw_end(&obj2);
+}
+
+static void make_obj3(int pretty)
+{
+	jw_object_begin(&obj3, pretty);
+	{
+		jw_object_intmax(&obj3, "a", 0);
+		jw_object_intmax(&obj3, "b", 0xffffffff);
+		jw_object_intmax(&obj3, "c", 0x7fffffffffffffffULL);
+	}
+	jw_end(&obj3);
+}
+
+static void make_obj4(int pretty)
+{
+	jw_object_begin(&obj4, pretty);
+	{
+		jw_object_true(&obj4, "t");
+		jw_object_false(&obj4, "f");
+		jw_object_null(&obj4, "n");
+	}
+	jw_end(&obj4);
+}
+
+static void make_obj5(int pretty)
+{
+	jw_object_begin(&obj5, pretty);
+	{
+		jw_object_string(&obj5, "abc" "\x09" "def", "abc" "\\" "def");
+	}
+	jw_end(&obj5);
+}
+
+static void make_obj6(int pretty)
+{
+	jw_object_begin(&obj6, pretty);
+	{
+		jw_object_double(&obj6, "a", 2, 3.14159);
+	}
+	jw_end(&obj6);
+}
+
+static const char *expect_arr1 = "[\"abc\",42,true]";
+static const char *expect_arr2 = "[-1,2147483647,0]";
+static const char *expect_arr3 = "[0,4294967295,9223372036854775807]";
+static const char *expect_arr4 = "[true,false,null]";
+
+static const char *pretty_arr1 = ("[\n"
+				  "  \"abc\",\n"
+				  "  42,\n"
+				  "  true\n"
+				  "]");
+static const char *pretty_arr2 = ("[\n"
+				  "  -1,\n"
+				  "  2147483647,\n"
+				  "  0\n"
+				  "]");
+static const char *pretty_arr3 = ("[\n"
+				  "  0,\n"
+				  "  4294967295,\n"
+				  "  9223372036854775807\n"
+				  "]");
+static const char *pretty_arr4 = ("[\n"
+				  "  true,\n"
+				  "  false,\n"
+				  "  null\n"
+				  "]");
+
+static struct json_writer arr1 = JSON_WRITER_INIT;
+static struct json_writer arr2 = JSON_WRITER_INIT;
+static struct json_writer arr3 = JSON_WRITER_INIT;
+static struct json_writer arr4 = JSON_WRITER_INIT;
+
+static void make_arr1(int pretty)
+{
+	jw_array_begin(&arr1, pretty);
+	{
+		jw_array_string(&arr1, "abc");
+		jw_array_intmax(&arr1, 42);
+		jw_array_true(&arr1);
+	}
+	jw_end(&arr1);
+}
+
+static void make_arr2(int pretty)
+{
+	jw_array_begin(&arr2, pretty);
+	{
+		jw_array_intmax(&arr2, -1);
+		jw_array_intmax(&arr2, 0x7fffffff);
+		jw_array_intmax(&arr2, 0);
+	}
+	jw_end(&arr2);
+}
+
+static void make_arr3(int pretty)
+{
+	jw_array_begin(&arr3, pretty);
+	{
+		jw_array_intmax(&arr3, 0);
+		jw_array_intmax(&arr3, 0xffffffff);
+		jw_array_intmax(&arr3, 0x7fffffffffffffffULL);
+	}
+	jw_end(&arr3);
+}
+
+static void make_arr4(int pretty)
+{
+	jw_array_begin(&arr4, pretty);
+	{
+		jw_array_true(&arr4);
+		jw_array_false(&arr4);
+		jw_array_null(&arr4);
+	}
+	jw_end(&arr4);
+}
+
+static char *expect_nest1 =
+	"{\"obj1\":{\"a\":\"abc\",\"b\":42,\"c\":true},\"arr1\":[\"abc\",42,true]}";
+
+static struct json_writer nest1 = JSON_WRITER_INIT;
+
+static void make_nest1(int pretty)
+{
+	jw_object_begin(&nest1, pretty);
+	{
+		jw_object_sub_jw(&nest1, "obj1", &obj1);
+		jw_object_sub_jw(&nest1, "arr1", &arr1);
+	}
+	jw_end(&nest1);
+}
+
+static char *expect_inline1 =
+	"{\"obj1\":{\"a\":\"abc\",\"b\":42,\"c\":true},\"arr1\":[\"abc\",42,true]}";
+
+static char *pretty_inline1 =
+	("{\n"
+	 "  \"obj1\": {\n"
+	 "    \"a\": \"abc\",\n"
+	 "    \"b\": 42,\n"
+	 "    \"c\": true\n"
+	 "  },\n"
+	 "  \"arr1\": [\n"
+	 "    \"abc\",\n"
+	 "    42,\n"
+	 "    true\n"
+	 "  ]\n"
+	 "}");
+
+static struct json_writer inline1 = JSON_WRITER_INIT;
+
+static void make_inline1(int pretty)
+{
+	jw_object_begin(&inline1, pretty);
+	{
+		jw_object_inline_begin_object(&inline1, "obj1");
+		{
+			jw_object_string(&inline1, "a", "abc");
+			jw_object_intmax(&inline1, "b", 42);
+			jw_object_true(&inline1, "c");
+		}
+		jw_end(&inline1);
+		jw_object_inline_begin_array(&inline1, "arr1");
+		{
+			jw_array_string(&inline1, "abc");
+			jw_array_intmax(&inline1, 42);
+			jw_array_true(&inline1);
+		}
+		jw_end(&inline1);
+	}
+	jw_end(&inline1);
+}
+
+static char *expect_inline2 =
+	"[[1,2],[3,4],{\"a\":\"abc\"}]";
+
+static char *pretty_inline2 =
+	("[\n"
+	 "  [\n"
+	 "    1,\n"
+	 "    2\n"
+	 "  ],\n"
+	 "  [\n"
+	 "    3,\n"
+	 "    4\n"
+	 "  ],\n"
+	 "  {\n"
+	 "    \"a\": \"abc\"\n"
+	 "  }\n"
+	 "]");
+
+static struct json_writer inline2 = JSON_WRITER_INIT;
+
+static void make_inline2(int pretty)
+{
+	jw_array_begin(&inline2, pretty);
+	{
+		jw_array_inline_begin_array(&inline2);
+		{
+			jw_array_intmax(&inline2, 1);
+			jw_array_intmax(&inline2, 2);
+		}
+		jw_end(&inline2);
+		jw_array_inline_begin_array(&inline2);
+		{
+			jw_array_intmax(&inline2, 3);
+			jw_array_intmax(&inline2, 4);
+		}
+		jw_end(&inline2);
+		jw_array_inline_begin_object(&inline2);
+		{
+			jw_object_string(&inline2, "a", "abc");
+		}
+		jw_end(&inline2);
+	}
+	jw_end(&inline2);
+}
+
+/*
+ * When super is compact, we expect subs to be compacted (even if originally
+ * pretty).
+ */
+static const char *expect_mixed1 =
+	("{\"obj1\":{\"a\":\"abc\",\"b\":42,\"c\":true},"
+	 "\"arr1\":[\"abc\",42,true]}");
+
+/*
+ * When super is pretty, a compact sub (obj1) is kept compact and a pretty
+ * sub (arr1) is re-indented.
+ */
+static const char *pretty_mixed1 =
+	("{\n"
+	 "  \"obj1\": {\"a\":\"abc\",\"b\":42,\"c\":true},\n"
+	 "  \"arr1\": [\n"
+	 "    \"abc\",\n"
+	 "    42,\n"
+	 "    true\n"
+	 "  ]\n"
+	 "}");
+
+static struct json_writer mixed1 = JSON_WRITER_INIT;
+
+static void make_mixed1(int pretty)
+{
+	jw_init(&obj1);
+	jw_init(&arr1);
+
+	make_obj1(0); /* obj1 is compact */
+	make_arr1(1); /* arr1 is pretty */
+
+	jw_object_begin(&mixed1, pretty);
+	{
+		jw_object_sub_jw(&mixed1, "obj1", &obj1);
+		jw_object_sub_jw(&mixed1, "arr1", &arr1);
+	}
+	jw_end(&mixed1);
+}
+
+static void cmp(const char *test, const struct json_writer *jw, const char *exp)
+{
+	if (!strcmp(jw->json.buf, exp))
+		return;
+
+	printf("error[%s]: observed '%s' expected '%s'\n",
+	       test, jw->json.buf, exp);
+	exit(1);
+}
+
+#define t(v) do { make_##v(0); cmp(#v, &v, expect_##v); } while (0)
+#define p(v) do { make_##v(1); cmp(#v, &v, pretty_##v); } while (0)
+
+/*
+ * Run some basic regression tests with some known patterns.
+ * These tests also demonstrate how to use the jw_ API.
+ */
+static int unit_tests(void)
+{
+	/* comptact (canonical) forms */
+	t(obj1);
+	t(obj2);
+	t(obj3);
+	t(obj4);
+	t(obj5);
+	t(obj6);
+
+	t(arr1);
+	t(arr2);
+	t(arr3);
+	t(arr4);
+
+	t(nest1);
+
+	t(inline1);
+	t(inline2);
+
+	jw_init(&obj1);
+	jw_init(&obj2);
+	jw_init(&obj3);
+	jw_init(&obj4);
+
+	jw_init(&arr1);
+	jw_init(&arr2);
+	jw_init(&arr3);
+	jw_init(&arr4);
+
+	jw_init(&inline1);
+	jw_init(&inline2);
+
+	/* pretty forms */
+	p(obj1);
+	p(obj2);
+	p(obj3);
+	p(obj4);
+
+	p(arr1);
+	p(arr2);
+	p(arr3);
+	p(arr4);
+
+	p(inline1);
+	p(inline2);
+
+	/* mixed forms */
+	t(mixed1);
+	jw_init(&mixed1);
+	p(mixed1);
+
+	return 0;
+}
+
+static void get_s(int line_nr, char **s_in)
+{
+	*s_in = strtok(NULL, " ");
+	if (!*s_in)
+		die("line[%d]: expected: <s>", line_nr);
+}
+
+static void get_i(int line_nr, intmax_t *s_in)
+{
+	char *s;
+	char *endptr;
+
+	get_s(line_nr, &s);
+
+	*s_in = strtol(s, &endptr, 10);
+	if (*endptr || errno == ERANGE)
+		die("line[%d]: invalid integer value", line_nr);
+}
+
+static void get_d(int line_nr, double *s_in)
+{
+	char *s;
+	char *endptr;
+
+	get_s(line_nr, &s);
+
+	*s_in = strtod(s, &endptr);
+	if (*endptr || errno == ERANGE)
+		die("line[%d]: invalid float value", line_nr);
+}
+
+static int pretty;
+
+#define MAX_LINE_LENGTH (64 * 1024)
+
+static char *get_trimmed_line(char *buf, int buf_size)
+{
+	int len;
+
+	if (!fgets(buf, buf_size, stdin))
+		return NULL;
+
+	len = strlen(buf);
+	while (len > 0) {
+		char c = buf[len - 1];
+		if (c == '\n' || c == '\r' || c == ' ' || c == '\t')
+			buf[--len] = 0;
+		else
+			break;
+	}
+
+	while (*buf == ' ' || *buf == '\t')
+		buf++;
+
+	return buf;
+}
+
+static int scripted(void)
+{
+	struct json_writer jw = JSON_WRITER_INIT;
+	char buf[MAX_LINE_LENGTH];
+	char *line;
+	int line_nr = 0;
+
+	line = get_trimmed_line(buf, MAX_LINE_LENGTH);
+	if (!line)
+		return 0;
+
+	if (!strcmp(line, "object"))
+		jw_object_begin(&jw, pretty);
+	else if (!strcmp(line, "array"))
+		jw_array_begin(&jw, pretty);
+	else
+		die("expected first line to be 'object' or 'array'");
+
+	while ((line = get_trimmed_line(buf, MAX_LINE_LENGTH)) != NULL) {
+		char *verb;
+		char *key;
+		char *s_value;
+		intmax_t i_value;
+		double d_value;
+
+		line_nr++;
+
+		verb = strtok(line, " ");
+
+		if (!strcmp(verb, "end")) {
+			jw_end(&jw);
+		}
+		else if (!strcmp(verb, "object-string")) {
+			get_s(line_nr, &key);
+			get_s(line_nr, &s_value);
+			jw_object_string(&jw, key, s_value);
+		}
+		else if (!strcmp(verb, "object-int")) {
+			get_s(line_nr, &key);
+			get_i(line_nr, &i_value);
+			jw_object_intmax(&jw, key, i_value);
+		}
+		else if (!strcmp(verb, "object-double")) {
+			get_s(line_nr, &key);
+			get_i(line_nr, &i_value);
+			get_d(line_nr, &d_value);
+			jw_object_double(&jw, key, i_value, d_value);
+		}
+		else if (!strcmp(verb, "object-true")) {
+			get_s(line_nr, &key);
+			jw_object_true(&jw, key);
+		}
+		else if (!strcmp(verb, "object-false")) {
+			get_s(line_nr, &key);
+			jw_object_false(&jw, key);
+		}
+		else if (!strcmp(verb, "object-null")) {
+			get_s(line_nr, &key);
+			jw_object_null(&jw, key);
+		}
+		else if (!strcmp(verb, "object-object")) {
+			get_s(line_nr, &key);
+			jw_object_inline_begin_object(&jw, key);
+		}
+		else if (!strcmp(verb, "object-array")) {
+			get_s(line_nr, &key);
+			jw_object_inline_begin_array(&jw, key);
+		}
+		else if (!strcmp(verb, "array-string")) {
+			get_s(line_nr, &s_value);
+			jw_array_string(&jw, s_value);
+		}
+		else if (!strcmp(verb, "array-int")) {
+			get_i(line_nr, &i_value);
+			jw_array_intmax(&jw, i_value);
+		}
+		else if (!strcmp(verb, "array-double")) {
+			get_i(line_nr, &i_value);
+			get_d(line_nr, &d_value);
+			jw_array_double(&jw, i_value, d_value);
+		}
+		else if (!strcmp(verb, "array-true"))
+			jw_array_true(&jw);
+		else if (!strcmp(verb, "array-false"))
+			jw_array_false(&jw);
+		else if (!strcmp(verb, "array-null"))
+			jw_array_null(&jw);
+		else if (!strcmp(verb, "array-object"))
+			jw_array_inline_begin_object(&jw);
+		else if (!strcmp(verb, "array-array"))
+			jw_array_inline_begin_array(&jw);
+		else
+			die("unrecognized token: '%s'", verb);
+	}
+
+	if (!jw_is_terminated(&jw))
+		die("json not terminated: '%s'", jw.json.buf);
+
+	printf("%s\n", jw.json.buf);
+
+	strbuf_release(&jw.json);
+	return 0;
+}
+
+int cmd__json_writer(int argc, const char **argv)
+{
+	argc--; /* skip over "json-writer" arg */
+	argv++;
+
+	if (argc > 0 && argv[0][0] == '-') {
+		if (!strcmp(argv[0], "-u") || !strcmp(argv[0], "--unit"))
+			return unit_tests();
+
+		if (!strcmp(argv[0], "-p") || !strcmp(argv[0], "--pretty"))
+			pretty = 1;
+	}
+
+	return scripted();
+}
diff --git a/t/helper/test-pkt-line.c b/t/helper/test-pkt-line.c
index 0f19e53c75..30775f986f 100644
--- a/t/helper/test-pkt-line.c
+++ b/t/helper/test-pkt-line.c
@@ -1,3 +1,4 @@
+#include "cache.h"
 #include "pkt-line.h"
 
 static void pack_line(const char *line)
@@ -48,6 +49,36 @@ static void unpack(void)
 	}
 }
 
+static void unpack_sideband(void)
+{
+	struct packet_reader reader;
+	packet_reader_init(&reader, 0, NULL, 0,
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_CHOMP_NEWLINE);
+
+	while (packet_reader_read(&reader) != PACKET_READ_EOF) {
+		int band;
+		int fd;
+
+		switch (reader.status) {
+		case PACKET_READ_EOF:
+			break;
+		case PACKET_READ_NORMAL:
+			band = reader.line[0] & 0xff;
+			if (band < 1 || band > 2)
+				die("unexpected side band %d", band);
+			fd = band;
+
+			write_or_die(fd, reader.line + 1, reader.pktlen - 1);
+			break;
+		case PACKET_READ_FLUSH:
+			return;
+		case PACKET_READ_DELIM:
+			break;
+		}
+	}
+}
+
 int cmd_main(int argc, const char **argv)
 {
 	if (argc < 2)
@@ -57,6 +88,8 @@ int cmd_main(int argc, const char **argv)
 		pack(argc - 2, argv + 2);
 	else if (!strcmp(argv[1], "unpack"))
 		unpack();
+	else if (!strcmp(argv[1], "unpack-sideband"))
+		unpack_sideband();
 	else
 		die("invalid argument '%s'", argv[1]);
 
diff --git a/t/helper/test-reach.c b/t/helper/test-reach.c
new file mode 100644
index 0000000000..eb21103998
--- /dev/null
+++ b/t/helper/test-reach.c
@@ -0,0 +1,130 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "commit.h"
+#include "commit-reach.h"
+#include "config.h"
+#include "parse-options.h"
+#include "ref-filter.h"
+#include "string-list.h"
+#include "tag.h"
+
+static void print_sorted_commit_ids(struct commit_list *list)
+{
+	int i;
+	struct string_list s = STRING_LIST_INIT_DUP;
+
+	while (list) {
+		string_list_append(&s, oid_to_hex(&list->item->object.oid));
+		list = list->next;
+	}
+
+	string_list_sort(&s);
+
+	for (i = 0; i < s.nr; i++)
+		printf("%s\n", s.items[i].string);
+
+	string_list_clear(&s, 0);
+}
+
+int cmd__reach(int ac, const char **av)
+{
+	struct object_id oid_A, oid_B;
+	struct commit *A, *B;
+	struct commit_list *X, *Y;
+	struct commit **X_array;
+	int X_nr, X_alloc;
+	struct strbuf buf = STRBUF_INIT;
+	struct repository *r = the_repository;
+
+	setup_git_directory();
+
+	if (ac < 2)
+		exit(1);
+
+	A = B = NULL;
+	X = Y = NULL;
+	X_nr = 0;
+	X_alloc = 16;
+	ALLOC_ARRAY(X_array, X_alloc);
+
+	while (strbuf_getline(&buf, stdin) != EOF) {
+		struct object_id oid;
+		struct object *o;
+		struct commit *c;
+		if (buf.len < 3)
+			continue;
+
+		if (get_oid_committish(buf.buf + 2, &oid))
+			die("failed to resolve %s", buf.buf + 2);
+
+		o = parse_object(r, &oid);
+		o = deref_tag_noverify(o);
+
+		if (!o)
+			die("failed to load commit for input %s resulting in oid %s\n",
+			    buf.buf, oid_to_hex(&oid));
+
+		c = object_as_type(r, o, OBJ_COMMIT, 0);
+
+		if (!c)
+			die("failed to load commit for input %s resulting in oid %s\n",
+			    buf.buf, oid_to_hex(&oid));
+
+		switch (buf.buf[0]) {
+			case 'A':
+				oidcpy(&oid_A, &oid);
+				A = c;
+				break;
+
+			case 'B':
+				oidcpy(&oid_B, &oid);
+				B = c;
+				break;
+
+			case 'X':
+				commit_list_insert(c, &X);
+				ALLOC_GROW(X_array, X_nr + 1, X_alloc);
+				X_array[X_nr++] = c;
+				break;
+
+			case 'Y':
+				commit_list_insert(c, &Y);
+				break;
+
+			default:
+				die("unexpected start of line: %c", buf.buf[0]);
+		}
+	}
+	strbuf_release(&buf);
+
+	if (!strcmp(av[1], "ref_newer"))
+		printf("%s(A,B):%d\n", av[1], ref_newer(&oid_A, &oid_B));
+	else if (!strcmp(av[1], "in_merge_bases"))
+		printf("%s(A,B):%d\n", av[1], in_merge_bases(A, B));
+	else if (!strcmp(av[1], "is_descendant_of"))
+		printf("%s(A,X):%d\n", av[1], is_descendant_of(A, X));
+	else if (!strcmp(av[1], "get_merge_bases_many")) {
+		struct commit_list *list = get_merge_bases_many(A, X_nr, X_array);
+		printf("%s(A,X):\n", av[1]);
+		print_sorted_commit_ids(list);
+	} else if (!strcmp(av[1], "reduce_heads")) {
+		struct commit_list *list = reduce_heads(X);
+		printf("%s(X):\n", av[1]);
+		print_sorted_commit_ids(list);
+	} else if (!strcmp(av[1], "can_all_from_reach")) {
+		printf("%s(X,Y):%d\n", av[1], can_all_from_reach(X, Y, 1));
+	} else if (!strcmp(av[1], "commit_contains")) {
+		struct ref_filter filter;
+		struct contains_cache cache;
+		init_contains_cache(&cache);
+
+		if (ac > 2 && !strcmp(av[2], "--tag"))
+			filter.with_commit_tag_algo = 1;
+		else
+			filter.with_commit_tag_algo = 0;
+
+		printf("%s(_,A,X,_):%d\n", av[1], commit_contains(&filter, A, X, &cache));
+	}
+
+	exit(0);
+}
diff --git a/t/helper/test-read-midx.c b/t/helper/test-read-midx.c
new file mode 100644
index 0000000000..831b586d02
--- /dev/null
+++ b/t/helper/test-read-midx.c
@@ -0,0 +1,51 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "midx.h"
+#include "repository.h"
+#include "object-store.h"
+
+static int read_midx_file(const char *object_dir)
+{
+	uint32_t i;
+	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+
+	if (!m)
+		return 1;
+
+	printf("header: %08x %d %d %d\n",
+	       m->signature,
+	       m->version,
+	       m->num_chunks,
+	       m->num_packs);
+
+	printf("chunks:");
+
+	if (m->chunk_pack_names)
+		printf(" pack-names");
+	if (m->chunk_oid_fanout)
+		printf(" oid-fanout");
+	if (m->chunk_oid_lookup)
+		printf(" oid-lookup");
+	if (m->chunk_object_offsets)
+		printf(" object-offsets");
+	if (m->chunk_large_offsets)
+		printf(" large-offsets");
+
+	printf("\nnum_objects: %d\n", m->num_objects);
+
+	printf("packs:\n");
+	for (i = 0; i < m->num_packs; i++)
+		printf("%s\n", m->pack_names[i]);
+
+	printf("object-dir: %s\n", m->object_dir);
+
+	return 0;
+}
+
+int cmd__read_midx(int argc, const char **argv)
+{
+	if (argc != 2)
+		usage("read-midx <object-dir>");
+
+	return read_midx_file(argv[1]);
+}
diff --git a/t/helper/test-repository.c b/t/helper/test-repository.c
new file mode 100644
index 0000000000..2762ca6562
--- /dev/null
+++ b/t/helper/test-repository.c
@@ -0,0 +1,82 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "commit-graph.h"
+#include "commit.h"
+#include "config.h"
+#include "object-store.h"
+#include "object.h"
+#include "repository.h"
+#include "tree.h"
+
+static void test_parse_commit_in_graph(const char *gitdir, const char *worktree,
+				       const struct object_id *commit_oid)
+{
+	struct repository r;
+	struct commit *c;
+	struct commit_list *parent;
+
+	repo_init(&r, gitdir, worktree);
+
+	c = lookup_commit(&r, commit_oid);
+
+	if (!parse_commit_in_graph(&r, c))
+		die("Couldn't parse commit");
+
+	printf("%"PRItime, c->date);
+	for (parent = c->parents; parent; parent = parent->next)
+		printf(" %s", oid_to_hex(&parent->item->object.oid));
+	printf("\n");
+
+	repo_clear(&r);
+}
+
+static void test_get_commit_tree_in_graph(const char *gitdir,
+					  const char *worktree,
+					  const struct object_id *commit_oid)
+{
+	struct repository r;
+	struct commit *c;
+	struct tree *tree;
+
+	repo_init(&r, gitdir, worktree);
+
+	c = lookup_commit(&r, commit_oid);
+
+	/*
+	 * get_commit_tree_in_graph does not automatically parse the commit, so
+	 * parse it first.
+	 */
+	if (!parse_commit_in_graph(&r, c))
+		die("Couldn't parse commit");
+	tree = get_commit_tree_in_graph(&r, c);
+	if (!tree)
+		die("Couldn't get commit tree");
+
+	printf("%s\n", oid_to_hex(&tree->object.oid));
+
+	repo_clear(&r);
+}
+
+int cmd__repository(int argc, const char **argv)
+{
+	if (argc < 2)
+		die("must have at least 2 arguments");
+	if (!strcmp(argv[1], "parse_commit_in_graph")) {
+		struct object_id oid;
+		if (argc < 5)
+			die("not enough arguments");
+		if (parse_oid_hex(argv[4], &oid, &argv[4]))
+			die("cannot parse oid '%s'", argv[4]);
+		test_parse_commit_in_graph(argv[2], argv[3], &oid);
+	} else if (!strcmp(argv[1], "get_commit_tree_in_graph")) {
+		struct object_id oid;
+		if (argc < 5)
+			die("not enough arguments");
+		if (parse_oid_hex(argv[4], &oid, &argv[4]))
+			die("cannot parse oid '%s'", argv[4]);
+		test_get_commit_tree_in_graph(argv[2], argv[3], &oid);
+	} else {
+		die("unrecognized '%s'", argv[1]);
+	}
+	return 0;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 805a45de9c..bef50c4dcc 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -19,6 +19,7 @@ static struct test_cmd cmds[] = {
 	{ "genrandom", cmd__genrandom },
 	{ "hashmap", cmd__hashmap },
 	{ "index-version", cmd__index_version },
+	{ "json-writer", cmd__json_writer },
 	{ "lazy-init-name-hash", cmd__lazy_init_name_hash },
 	{ "match-trees", cmd__match_trees },
 	{ "mergesort", cmd__mergesort },
@@ -26,9 +27,12 @@ static struct test_cmd cmds[] = {
 	{ "online-cpus", cmd__online_cpus },
 	{ "path-utils", cmd__path_utils },
 	{ "prio-queue", cmd__prio_queue },
+	{ "reach", cmd__reach },
 	{ "read-cache", cmd__read_cache },
+	{ "read-midx", cmd__read_midx },
 	{ "ref-store", cmd__ref_store },
 	{ "regex", cmd__regex },
+	{ "repository", cmd__repository },
 	{ "revision-walking", cmd__revision_walking },
 	{ "run-command", cmd__run_command },
 	{ "scrap-cache-tree", cmd__scrap_cache_tree },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 7116ddfb94..321982e4bc 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -1,6 +1,8 @@
 #ifndef __TEST_TOOL_H__
 #define __TEST_TOOL_H__
 
+#include "git-compat-util.h"
+
 int cmd__chmtime(int argc, const char **argv);
 int cmd__config(int argc, const char **argv);
 int cmd__ctype(int argc, const char **argv);
@@ -13,6 +15,7 @@ int cmd__example_decorate(int argc, const char **argv);
 int cmd__genrandom(int argc, const char **argv);
 int cmd__hashmap(int argc, const char **argv);
 int cmd__index_version(int argc, const char **argv);
+int cmd__json_writer(int argc, const char **argv);
 int cmd__lazy_init_name_hash(int argc, const char **argv);
 int cmd__match_trees(int argc, const char **argv);
 int cmd__mergesort(int argc, const char **argv);
@@ -20,9 +23,12 @@ int cmd__mktemp(int argc, const char **argv);
 int cmd__online_cpus(int argc, const char **argv);
 int cmd__path_utils(int argc, const char **argv);
 int cmd__prio_queue(int argc, const char **argv);
+int cmd__reach(int argc, const char **argv);
 int cmd__read_cache(int argc, const char **argv);
+int cmd__read_midx(int argc, const char **argv);
 int cmd__ref_store(int argc, const char **argv);
 int cmd__regex(int argc, const char **argv);
+int cmd__repository(int argc, const char **argv);
 int cmd__revision_walking(int argc, const char **argv);
 int cmd__run_command(int argc, const char **argv);
 int cmd__scrap_cache_tree(int argc, const char **argv);