t/helper: add 'find-pack' test-tool

In a following commit, we will make it possible to separate objects in
different packfiles depending on a filter.

To make sure that the right objects are in the right packs, let's add a
new test-tool that can display which packfile(s) a given object is in.

Let's also make it possible to check if a given object is in the
expected number of packfiles with a `--check-count <n>` option.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -800,6 +800,7 @@ TEST_BUILTINS_OBJS += test-dump-untracked-cache.o
 TEST_BUILTINS_OBJS += test-env-helper.o
 TEST_BUILTINS_OBJS += test-example-decorate.o
 TEST_BUILTINS_OBJS += test-fast-rebase.o
+TEST_BUILTINS_OBJS += test-find-pack.o
 TEST_BUILTINS_OBJS += test-fsmonitor-client.o
 TEST_BUILTINS_OBJS += test-genrandom.o
 TEST_BUILTINS_OBJS += test-genzeros.o

t/helper/test-find-pack.c

@@ -0,0 +1,50 @@
+#include "test-tool.h"
+#include "object-name.h"
+#include "object-store.h"
+#include "packfile.h"
+#include "parse-options.h"
+#include "setup.h"
+
+/*
+ * Display the path(s), one per line, of the packfile(s) containing
+ * the given object.
+ *
+ * If '--check-count <n>' is passed, then error out if the number of
+ * packfiles containing the object is not <n>.
+ */
+
+static const char *find_pack_usage[] = {
+	"test-tool find-pack [--check-count <n>] <object>",
+	NULL
+};
+
+int cmd__find_pack(int argc, const char **argv)
+{
+	struct object_id oid;
+	struct packed_git *p;
+	int count = -1, actual_count = 0;
+	const char *prefix = setup_git_directory();
+
+	struct option options[] = {
+		OPT_INTEGER('c', "check-count", &count, "expected number of packs"),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, prefix, options, find_pack_usage, 0);
+	if (argc != 1)
+		usage(find_pack_usage[0]);
+
+	if (repo_get_oid(the_repository, argv[0], &oid))
+		die("cannot parse %s as an object name", argv[0]);
+
+	for (p = get_all_packs(the_repository); p; p = p->next)
+		if (find_pack_entry_one(oid.hash, p)) {
+			printf("%s\n", p->pack_name);
+			actual_count++;
+		}
+
+	if (count > -1 && count != actual_count)
+		die("bad packfile count %d instead of %d", actual_count, count);
+
+	return 0;
+}

t/helper/test-tool.c

@@ -31,6 +31,7 @@ static struct test_cmd cmds[] = {
 	{ "env-helper", cmd__env_helper },
 	{ "example-decorate", cmd__example_decorate },
 	{ "fast-rebase", cmd__fast_rebase },
+	{ "find-pack", cmd__find_pack },
 	{ "fsmonitor-client", cmd__fsmonitor_client },
 	{ "genrandom", cmd__genrandom },
 	{ "genzeros", cmd__genzeros },

t/helper/test-tool.h

@@ -25,6 +25,7 @@ int cmd__dump_reftable(int argc, const char **argv);
 int cmd__env_helper(int argc, const char **argv);
 int cmd__example_decorate(int argc, const char **argv);
 int cmd__fast_rebase(int argc, const char **argv);
+int cmd__find_pack(int argc, const char **argv);
 int cmd__fsmonitor_client(int argc, const char **argv);
 int cmd__genrandom(int argc, const char **argv);
 int cmd__genzeros(int argc, const char **argv);

t/t0081-find-pack.sh

@@ -0,0 +1,82 @@
+#!/bin/sh
+
+test_description='test `test-tool find-pack`'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit one &&
+	test_commit two &&
+	test_commit three &&
+	test_commit four &&
+	test_commit five
+'
+
+test_expect_success 'repack everything into a single packfile' '
+	git repack -a -d --no-write-bitmap-index &&
+
+	head_commit_pack=$(test-tool find-pack HEAD) &&
+	head_tree_pack=$(test-tool find-pack HEAD^{tree}) &&
+	one_pack=$(test-tool find-pack HEAD:one.t) &&
+	three_pack=$(test-tool find-pack HEAD:three.t) &&
+	old_commit_pack=$(test-tool find-pack HEAD~4) &&
+
+	test-tool find-pack --check-count 1 HEAD &&
+	test-tool find-pack --check-count=1 HEAD^{tree} &&
+	! test-tool find-pack --check-count=0 HEAD:one.t &&
+	! test-tool find-pack -c 2 HEAD:one.t &&
+	test-tool find-pack -c 1 HEAD:three.t &&
+
+	# Packfile exists at the right path
+	case "$head_commit_pack" in
+		".git/objects/pack/pack-"*".pack") true ;;
+		*) false ;;
+	esac &&
+	test -f "$head_commit_pack" &&
+
+	# Everything is in the same pack
+	test "$head_commit_pack" = "$head_tree_pack" &&
+	test "$head_commit_pack" = "$one_pack" &&
+	test "$head_commit_pack" = "$three_pack" &&
+	test "$head_commit_pack" = "$old_commit_pack"
+'
+
+test_expect_success 'add more packfiles' '
+	git rev-parse HEAD^{tree} HEAD:two.t HEAD:four.t >objects &&
+	git pack-objects .git/objects/pack/mypackname1 >packhash1 <objects &&
+
+	git rev-parse HEAD~ HEAD~^{tree} HEAD:five.t >objects &&
+	git pack-objects .git/objects/pack/mypackname2 >packhash2 <objects &&
+
+	head_commit_pack=$(test-tool find-pack HEAD) &&
+
+	# HEAD^{tree} is in 2 packfiles
+	test-tool find-pack HEAD^{tree} >head_tree_packs &&
+	grep "$head_commit_pack" head_tree_packs &&
+	grep mypackname1 head_tree_packs &&
+	! grep mypackname2 head_tree_packs &&
+	test-tool find-pack --check-count 2 HEAD^{tree} &&
+	! test-tool find-pack --check-count 1 HEAD^{tree} &&
+
+	# HEAD:five.t is also in 2 packfiles
+	test-tool find-pack HEAD:five.t >five_packs &&
+	grep "$head_commit_pack" five_packs &&
+	! grep mypackname1 five_packs &&
+	grep mypackname2 five_packs &&
+	test-tool find-pack -c 2 HEAD:five.t &&
+	! test-tool find-pack --check-count=0 HEAD:five.t
+'
+
+test_expect_success 'add more commits (as loose objects)' '
+	test_commit six &&
+	test_commit seven &&
+
+	test -z "$(test-tool find-pack HEAD)" &&
+	test -z "$(test-tool find-pack HEAD:six.t)" &&
+	test-tool find-pack --check-count 0 HEAD &&
+	test-tool find-pack -c 0 HEAD:six.t &&
+	! test-tool find-pack -c 1 HEAD:seven.t
+'
+
+test_done