Merge branch 'zh/gc-expire-to'

"git gc" learned the "--expire-to" option and passes it down to
underlying "git repack".

* zh/gc-expire-to:
  gc: add `--expire-to` option

Documentation/git-gc.txt

@@ -69,6 +69,13 @@ be performed as well.
 	the `--max-cruft-size` option of linkgit:git-repack[1] for
 	more.
 
+--expire-to=<dir>::
+	When packing unreachable objects into a cruft pack, write a cruft
+	pack containing pruned objects (if any) to the directory `<dir>`.
+	This option only has an effect when used together with `--cruft`.
+	See the `--expire-to` option of linkgit:git-repack[1] for
+	more information.
+
 --prune=<date>::
 	Prune loose objects older than date (default is 2 weeks ago,
 	overridable by the config variable `gc.pruneExpire`).

builtin/gc.c

@@ -139,6 +139,7 @@ struct gc_config {
 	char *prune_worktrees_expire;
 	char *repack_filter;
 	char *repack_filter_to;
+	char *repack_expire_to;
 	unsigned long big_pack_threshold;
 	unsigned long max_delta_cache_size;
 	/*
@@ -445,7 +446,8 @@ static int keep_one_pack(struct string_list_item *item, void *data UNUSED)
 static void add_repack_all_option(struct gc_config *cfg,
 				  struct string_list *keep_pack)
 {
-	if (cfg->prune_expire && !strcmp(cfg->prune_expire, "now"))
+	if (cfg->prune_expire && !strcmp(cfg->prune_expire, "now")
+		&& !(cfg->cruft_packs && cfg->repack_expire_to))
 		strvec_push(&repack, "-a");
 	else if (cfg->cruft_packs) {
 		strvec_push(&repack, "--cruft");
@@ -454,6 +456,8 @@ static void add_repack_all_option(struct gc_config *cfg,
 		if (cfg->max_cruft_size)
 			strvec_pushf(&repack, "--max-cruft-size=%lu",
 				     cfg->max_cruft_size);
+		if (cfg->repack_expire_to)
+			strvec_pushf(&repack, "--expire-to=%s", cfg->repack_expire_to);
 	} else {
 		strvec_push(&repack, "-A");
 		if (cfg->prune_expire)
@@ -688,7 +692,6 @@ struct repository *repo UNUSED)
 	const char *prune_expire_sentinel = "sentinel";
 	const char *prune_expire_arg = prune_expire_sentinel;
 	int ret;
-
 	struct option builtin_gc_options[] = {
 		OPT__QUIET(&quiet, N_("suppress progress reporting")),
 		{ OPTION_STRING, 0, "prune", &prune_expire_arg, N_("date"),
@@ -707,6 +710,8 @@ struct repository *repo UNUSED)
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL(0, "keep-largest-pack", &keep_largest_pack,
 			 N_("repack all other packs except the largest pack")),
+		OPT_STRING(0, "expire-to", &cfg.repack_expire_to, N_("dir"),
+			   N_("pack prefix to store a pack containing pruned objects")),
 		OPT_END()
 	};
 

t/t6500-gc.sh

@@ -338,6 +338,39 @@ test_expect_success 'gc.maxCruftSize sets appropriate repack options' '
 	test_subcommand $cruft_max_size_opts --max-cruft-size=3145728 <trace2.txt
 '
 
+test_expect_success '--expire-to sets repack --expire-to' '
+	rm -rf expired &&
+	mkdir expired &&
+	expire_to="$(pwd)/expired/pack" &&
+	GIT_TRACE2_EVENT=$(pwd)/trace2.txt git -C cruft--max-size gc --cruft --expire-to="$expire_to" &&
+	test_subcommand $cruft_max_size_opts --expire-to="$expire_to" <trace2.txt
+'
+
+test_expect_success '--expire-to with --prune=now sets repack --expire-to' '
+	rm -rf expired &&
+	mkdir expired &&
+	expire_to="$(pwd)/expired/pack" &&
+	GIT_TRACE2_EVENT=$(pwd)/trace2.txt git -C cruft--max-size gc --cruft --prune=now --expire-to="$expire_to" &&
+	test_subcommand git repack -d -l --cruft --cruft-expiration=now --expire-to="$expire_to" <trace2.txt
+'
+
+
+test_expect_success '--expire-to with --no-cruft sets repack -A' '
+	rm -rf expired &&
+	mkdir expired &&
+	expire_to="$(pwd)/expired/pack" &&
+	GIT_TRACE2_EVENT=$(pwd)/trace2.txt git -C cruft--max-size gc --no-cruft --expire-to="$expire_to" &&
+	test_subcommand git repack -d -l -A --unpack-unreachable=2.weeks.ago <trace2.txt
+'
+
+test_expect_success '--expire-to with --no-cruft sets repack -a' '
+	rm -rf expired &&
+	mkdir expired &&
+	expire_to="$(pwd)/expired/pack" &&
+	GIT_TRACE2_EVENT=$(pwd)/trace2.txt git -C cruft--max-size gc --no-cruft --prune=now --expire-to="$expire_to" &&
+	test_subcommand git repack -d -l -a <trace2.txt
+'
+
 run_and_wait_for_gc () {
 	# We read stdout from gc for the side effect of waiting until the
 	# background gc process exits, closing its fd 9.  Furthermore, the