repack: add --name-hash-version option

The new '--name-hash-version' option for 'git repack' is a simple
pass-through to the underlying 'git pack-objects' subcommand. However,
this subcommand may have other options and a temporary filename as part
of the subcommand execution that may not be predictable or could change
over time.

The existing test_subcommand method requires an exact list of arguments
for the subcommand. This is too rigid for our needs here, so create a
new method, test_subcommand_flex. Use it to check that the
--name-hash-version option is passing through.

Since we are modifying the 'git repack' command, let's bring its usage
in line with the Documentation's synopsis. This removes it from the
allow list in t0450 so it will remain in sync in the future.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-repack.txt

@@ -9,7 +9,9 @@ git-repack - Pack unpacked objects in a repository
 SYNOPSIS
 --------
 [verse]
-'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m] [--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>] [--write-midx]
+'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m]
+	[--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]
+	[--write-midx] [--name-hash-version=<n>]
 
 DESCRIPTION
 -----------
@@ -249,6 +251,11 @@ linkgit:git-multi-pack-index[1]).
 	Write a multi-pack index (see linkgit:git-multi-pack-index[1])
 	containing the non-redundant packs.
 
+--name-hash-version=<n>::
+	Provide this argument to the underlying `git pack-objects` process.
+	See linkgit:git-pack-objects[1] for full details.
+
+
 CONFIGURATION
 -------------
 

builtin/repack.c

@@ -39,7 +39,9 @@ static int run_update_server_info = 1;
 static char *packdir, *packtmp_name, *packtmp;
 
 static const char *const git_repack_usage[] = {
-	N_("git repack [<options>]"),
+	N_("git repack [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m]\n"
+	   "[--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]\n"
+	   "[--write-midx] [--name-hash-version=<n>]"),
 	NULL
 };
 
@@ -58,6 +60,7 @@ struct pack_objects_args {
 	int no_reuse_object;
 	int quiet;
 	int local;
+	int name_hash_version;
 	struct list_objects_filter_options filter_options;
 };
 
@@ -306,6 +309,8 @@ static void prepare_pack_objects(struct child_process *cmd,
 		strvec_pushf(&cmd->args, "--no-reuse-delta");
 	if (args->no_reuse_object)
 		strvec_pushf(&cmd->args, "--no-reuse-object");
+	if (args->name_hash_version)
+		strvec_pushf(&cmd->args, "--name-hash-version=%d", args->name_hash_version);
 	if (args->local)
 		strvec_push(&cmd->args,  "--local");
 	if (args->quiet)
@@ -1203,6 +1208,8 @@ int cmd_repack(int argc,
 				N_("pass --no-reuse-delta to git-pack-objects")),
 		OPT_BOOL('F', NULL, &po_args.no_reuse_object,
 				N_("pass --no-reuse-object to git-pack-objects")),
+		OPT_INTEGER(0, "name-hash-version", &po_args.name_hash_version,
+				N_("specify the name hash version to use for grouping similar objects by path")),
 		OPT_NEGBIT('n', NULL, &run_update_server_info,
 				N_("do not run git-update-server-info"), 1),
 		OPT__QUIET(&po_args.quiet, N_("be quiet")),

t/t0450/txt-help-mismatches

@@ -45,7 +45,6 @@ rebase
 remote
 remote-ext
 remote-fd
-repack
 reset
 restore
 rev-parse

t/t7700-repack.sh

@@ -777,6 +777,12 @@ test_expect_success 'repack -ad cleans up old .tmp-* packs' '
 	test_must_be_empty tmpfiles
 '
 
+test_expect_success '--name-hash-version option passes through to pack-objects' '
+	GIT_TRACE2_EVENT="$(pwd)/hash-trace.txt" \
+		git repack -a --name-hash-version=2 &&
+	test_subcommand_flex git pack-objects --name-hash-version=2 <hash-trace.txt
+'
+
 test_expect_success 'setup for update-server-info' '
 	git init update-server-info &&
 	test_commit -C update-server-info message

t/test-lib-functions.sh

@@ -1886,6 +1886,32 @@ test_subcommand () {
 	fi
 }
 
+# Check that the given subcommand was run with the given set of
+# arguments in order (but with possible extra arguments).
+#
+#	test_subcommand_flex [!] <command> <args>... < <trace>
+#
+# If the first parameter passed is !, this instead checks that
+# the given command was not called.
+#
+test_subcommand_flex () {
+	local negate=
+	if test "$1" = "!"
+	then
+		negate=t
+		shift
+	fi
+
+	local expr="$(printf '"%s".*' "$@")"
+
+	if test -n "$negate"
+	then
+		! grep "\[$expr\]"
+	else
+		grep "\[$expr\]"
+	fi
+}
+
 # Check that the given command was invoked as part of the
 # trace2-format trace on stdin.
 #