Parial clone part 3: clone, fetch, fetch-pack, upload-pack, and tests

index 9b28322..c6bfc11 100644
@@ -79,3 +79,4 @@ int opt_parse_list_objects_filter(const struct option *opt,
 
 	return parse_list_objects_filter(filter_options, arg);
 }
+

index e25f725..eb07429 100644
@@ -10,6 +10,8 @@
 #include "diff.h"
 #include "revision.h"
 #include "list-objects.h"
+#include "list-objects-filter.h"
+#include "list-objects-filter-options.h"
 #include "run-command.h"
 #include "connect.h"
 #include "sigchain.h"

@@ -64,6 +66,10 @@ static int advertise_refs;
 static int stateless_rpc;
 static const char *pack_objects_hook;
 
+static int filter_capability_requested;
+static int filter_advertise;
+static struct list_objects_filter_options filter_options;
+
 static void reset_timeout(void)
 {
 	alarm(timeout);

@@ -131,6 +137,9 @@ static void create_pack_file(void)
 		argv_array_push(&pack_objects.args, "--delta-base-offset");
 	if (use_include_tag)
 		argv_array_push(&pack_objects.args, "--include-tag");
+	if (filter_options.choice)
+		argv_array_pushf(&pack_objects.args, "--%s=%s", CL_ARG__FILTER,
+				 filter_options.filter_spec);
 
 	pack_objects.in = -1;
 	pack_objects.out = -1;

@@ -794,6 +803,12 @@ static void receive_needs(void)
 			deepen_rev_list = 1;
 			continue;
 		}
+		if (skip_prefix(line, "filter ", &arg)) {
+			if (!filter_capability_requested)
+				die("git upload-pack: filtering capability not negotiated");
+			parse_list_objects_filter(&filter_options, arg);
+			continue;
+		}
 		if (!skip_prefix(line, "want ", &arg) ||
 		    get_oid_hex(arg, &oid_buf))
 			die("git upload-pack: protocol error, "

@@ -821,6 +836,8 @@ static void receive_needs(void)
 			no_progress = 1;
 		if (parse_feature_request(features, "include-tag"))
 			use_include_tag = 1;
+		if (parse_feature_request(features, "filter"))
+			filter_capability_requested = 1;
 
 		o = parse_object(&oid_buf);
 		if (!o) {

@@ -940,7 +957,7 @@ static int send_ref(const char *refname, const struct object_id *oid,
 		struct strbuf symref_info = STRBUF_INIT;
 
 		format_symref_info(&symref_info, cb_data);
-		packet_write_fmt(1, "%s %s%c%s%s%s%s%s agent=%s\n",
+		packet_write_fmt(1, "%s %s%c%s%s%s%s%s%s agent=%s\n",
 			     oid_to_hex(oid), refname_nons,
 			     0, capabilities,
 			     (allow_unadvertised_object_request & ALLOW_TIP_SHA1) ?

@@ -949,6 +966,7 @@ static int send_ref(const char *refname, const struct object_id *oid,
 				     " allow-reachable-sha1-in-want" : "",
 			     stateless_rpc ? " no-done" : "",
 			     symref_info.buf,
+			     filter_advertise ? " filter" : "",
 			     git_user_agent_sanitized());
 		strbuf_release(&symref_info);
 	} else {

@@ -1027,6 +1045,8 @@ static int upload_pack_config(const char *var, const char *value, void *unused)
 	} else if (current_config_scope() != CONFIG_SCOPE_REPO) {
 		if (!strcmp("uploadpack.packobjectshook", var))
 			return git_config_string(&pack_objects_hook, var, value);
+	} else if (!strcmp("uploadpack.allowfilter", var)) {
+		filter_advertise = git_config_bool(var, value);
 	}
 	return parse_hide_refs_config(var, value, "uploadpack");
 }

index dbddd98..0a8ac76 100644
@@ -26,6 +26,7 @@
 #include "run-command.h"
 #include "connected.h"
 #include "packfile.h"
+#include "list-objects-filter-options.h"
 
 /*
  * Overall FIXMEs:

@@ -60,6 +61,7 @@ static struct string_list option_optional_reference = STRING_LIST_INIT_NODUP;
 static int option_dissociate;
 static int max_jobs = -1;
 static struct string_list option_recurse_submodules = STRING_LIST_INIT_NODUP;
+static struct list_objects_filter_options filter_options;
 
 static int recurse_submodules_cb(const struct option *opt,
 				 const char *arg, int unset)

@@ -135,6 +137,7 @@ static struct option builtin_clone_options[] = {
 			TRANSPORT_FAMILY_IPV4),
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
 			TRANSPORT_FAMILY_IPV6),
+	OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
 	OPT_END()
 };
 

@@ -1073,6 +1076,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 			warning(_("--shallow-since is ignored in local clones; use file:// instead."));
 		if (option_not.nr)
 			warning(_("--shallow-exclude is ignored in local clones; use file:// instead."));
+		if (filter_options.choice)
+			warning(_("--filter is ignored in local clones; use file:// instead."));
 		if (!access(mkpath("%s/shallow", path), F_OK)) {
 			if (option_local > 0)
 				warning(_("source repository is shallow, ignoring --local"));

@@ -1104,6 +1109,10 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK,
 				     option_upload_pack);
 
+	if (filter_options.choice)
+		transport_set_option(transport, TRANS_OPT_LIST_OBJECTS_FILTER,
+				     filter_options.filter_spec);
+
 	if (transport->smart_options && !deepen)
 		transport->smart_options->check_self_contained_and_connected = 1;
 

index 9a7ebf6..d0fdaa8 100644
@@ -153,6 +153,10 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 			args.no_haves = 1;
 			continue;
 		}
+		if (skip_prefix(arg, ("--" CL_ARG__FILTER "="), &arg)) {
+			parse_list_objects_filter(&args.filter_options, arg);
+			continue;
+		}
 		usage(fetch_pack_usage);
 	}
 	if (deepen_not.nr)

index 4640b4e..2b04251 100644
@@ -29,6 +29,7 @@ static int deepen_not_ok;
 static int fetch_fsck_objects = -1;
 static int transfer_fsck_objects = -1;
 static int agent_supported;
+static int server_supports_filtering;
 static struct lock_file shallow_lock;
 static const char *alternate_shallow_file;
 

@@ -379,6 +380,8 @@ static int find_common(struct fetch_pack_args *args,
 			if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 			if (agent_supported)    strbuf_addf(&c, " agent=%s",
 							    git_user_agent_sanitized());
+			if (args->filter_options.choice)
+				strbuf_addstr(&c, " filter");
 			packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 			strbuf_release(&c);
 		} else

@@ -407,6 +410,9 @@ static int find_common(struct fetch_pack_args *args,
 			packet_buf_write(&req_buf, "deepen-not %s", s->string);
 		}
 	}
+	if (server_supports_filtering && args->filter_options.choice)
+		packet_buf_write(&req_buf, "filter %s",
+				 args->filter_options.filter_spec);
 	packet_buf_flush(&req_buf);
 	state_len = req_buf.len;
 

@@ -967,6 +973,13 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 	else
 		prefer_ofs_delta = 0;
 
+	if (server_supports("filter")) {
+		server_supports_filtering = 1;
+		print_verbose(args, _("Server supports filter"));
+	} else if (args->filter_options.choice) {
+		warning("filtering not recognized by server, ignoring");
+	}
+
 	if ((agent_feature = server_feature_value("agent", &agent_len))) {
 		agent_supported = 1;
 		if (agent_len)

index 84904c3..64661b6 100644
@@ -3,6 +3,7 @@
 
 #include "string-list.h"
 #include "run-command.h"
+#include "list-objects-filter-options.h"
 
 struct oid_array;
 

@@ -12,6 +13,7 @@ struct fetch_pack_args {
 	int depth;
 	const char *deepen_since;
 	const struct string_list *deepen_not;
+	struct list_objects_filter_options filter_options;
 	unsigned deepen_relative:1;
 	unsigned quiet:1;
 	unsigned keep_pack:1;

index c948d52..0650ca0 100644
@@ -671,6 +671,11 @@ static int fetch(struct transport *transport,
 	if (data->transport_options.update_shallow)
 		set_helper_option(transport, "update-shallow", "true");
 
+	if (data->transport_options.filter_options.choice)
+		set_helper_option(
+			transport, "filter",
+			data->transport_options.filter_options.filter_spec);
+
 	if (data->fetch)
 		return fetch_with_fetch(transport, nr_heads, to_fetch);
 

index 8211f82..d50c73b 100644
@@ -166,6 +166,9 @@ static int set_git_option(struct git_transport_options *opts,
 	} else if (!strcmp(name, TRANS_OPT_NO_HAVES)) {
 		opts->no_haves = !!value;
 		return 0;
+	} else if (!strcmp(name, TRANS_OPT_LIST_OBJECTS_FILTER)) {
+		parse_list_objects_filter(&opts->filter_options, value);
+		return 0;
 	}
 	return 1;
 }

@@ -236,6 +239,7 @@ static int fetch_refs_via_pack(struct transport *transport,
 	args.update_shallow = data->options.update_shallow;
 	args.from_promisor = data->options.from_promisor;
 	args.no_haves = data->options.no_haves;
+	args.filter_options = data->options.filter_options;
 
 	if (!data->got_remote_heads) {
 		connect_setup(transport, 0);

index 67428f6..f64aa3a 100644
@@ -4,6 +4,7 @@
 #include "cache.h"
 #include "run-command.h"
 #include "remote.h"
+#include "list-objects-filter-options.h"
 
 struct string_list;
 

@@ -23,6 +24,7 @@ struct git_transport_options {
 	const char *uploadpack;
 	const char *receivepack;
 	struct push_cas_option *cas;
+	struct list_objects_filter_options filter_options;
 };
 
 enum transport_family {

@@ -218,6 +220,9 @@ void transport_check_allowed(const char *type);
 /* Do not send "have" lines */
 #define TRANS_OPT_NO_HAVES "no-haves"
 
+/* Filter objects for partial clone and fetch */
+#define TRANS_OPT_LIST_OBJECTS_FILTER "filter"
+
 /**
  * Returns 0 if the option was used, non-zero otherwise. Prints a
  * message to stderr if the option is not used.

index 225c734..1b1f039 100644
@@ -1322,7 +1322,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 {
 	int i;
 	struct string_list list = STRING_LIST_INIT_DUP;
-	struct remote *remote;
+	struct remote *remote = NULL;
 	int result = 0;
 	struct argv_array argv_gc_auto = ARGV_ARRAY_INIT;
 

@@ -1367,17 +1367,14 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		else if (argc > 1)
 			die(_("fetch --all does not make sense with refspecs"));
 		(void) for_each_remote(get_one_remote_for_fetch, &list);
-		result = fetch_multiple(&list);
 	} else if (argc == 0) {
 		/* No arguments -- use default remote */
 		remote = remote_get(NULL);
-		result = fetch_one(remote, argc, argv);
 	} else if (multiple) {
 		/* All arguments are assumed to be remotes or groups */
 		for (i = 0; i < argc; i++)
 			if (!add_remote_or_group(argv[i], &list))
 				die(_("No such remote or remote group: %s"), argv[i]);
-		result = fetch_multiple(&list);
 	} else {
 		/* Single remote or group */
 		(void) add_remote_or_group(argv[0], &list);

@@ -1385,14 +1382,19 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 			/* More than one remote */
 			if (argc > 1)
 				die(_("Fetching a group and specifying refspecs does not make sense"));
-			result = fetch_multiple(&list);
 		} else {
 			/* Zero or one remotes */
 			remote = remote_get(argv[0]);
-			result = fetch_one(remote, argc-1, argv+1);
+			argc--;
+			argv++;
 		}
 	}
 
+	if (remote)
+		result = fetch_one(remote, argc, argv);
+	else
+		result = fetch_multiple(&list);
+
 	if (!result && (recurse_submodules != RECURSE_SUBMODULES_OFF)) {
 		struct argv_array options = ARGV_ARRAY_INIT;
 

index 1b1f039..29d3807 100644
@@ -18,6 +18,7 @@
 #include "argv-array.h"
 #include "utf8.h"
 #include "packfile.h"
+#include "list-objects-filter-options.h"
 
 static const char * const builtin_fetch_usage[] = {
 	N_("git fetch [<options>] [<repository> [<refspec>...]]"),

@@ -55,6 +56,7 @@ static int recurse_submodules_default = RECURSE_SUBMODULES_ON_DEMAND;
 static int shown_url = 0;
 static int refmap_alloc, refmap_nr;
 static const char **refmap_array;
+static struct list_objects_filter_options filter_options;
 
 static int git_fetch_config(const char *k, const char *v, void *cb)
 {

@@ -160,6 +162,7 @@ static struct option builtin_fetch_options[] = {
 			TRANSPORT_FAMILY_IPV4),
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
 			TRANSPORT_FAMILY_IPV6),
+	OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
 	OPT_END()
 };
 

@@ -1044,6 +1047,9 @@ static struct transport *prepare_transport(struct remote *remote, int deepen)
 		set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, "yes");
 	if (update_shallow)
 		set_option(transport, TRANS_OPT_UPDATE_SHALLOW, "yes");
+	if (filter_options.choice)
+		set_option(transport, TRANS_OPT_LIST_OBJECTS_FILTER,
+			   filter_options.filter_spec);
 	return transport;
 }
 

@@ -1242,6 +1248,20 @@ static int fetch_multiple(struct string_list *list)
 	int i, result = 0;
 	struct argv_array argv = ARGV_ARRAY_INIT;
 
+	if (filter_options.choice) {
+		/*
+		 * We currently only support partial-fetches to the remote
+		 * used for the partial-clone because we only support 1
+		 * promisor remote, so we DO NOT allow explicit command
+		 * line filter arguments for multi-fetches.
+		 *
+		 * Note that the loop below will spawn background fetches
+		 * for each remote and one of them MAY INHERIT the proper
+		 * partial-fetch settings, so everything is consistent.
+		 */
+		die(_("partial-fetch is not supported on multiple remotes"));
+	}
+
 	if (!append && !dry_run) {
 		int errcode = truncate_fetch_head();
 		if (errcode)

index 34a81b8..31a3d8d 100644
@@ -13,6 +13,7 @@
 #include "credential.h"
 #include "sha1-array.h"
 #include "send-pack.h"
+#include "list-objects-filter-options.h"
 
 static struct remote *remote;
 /* always ends with a trailing slash */

@@ -22,6 +23,7 @@ struct options {
 	int verbosity;
 	unsigned long depth;
 	char *deepen_since;
+	char *partial_clone_filter;
 	struct string_list deepen_not;
 	struct string_list push_options;
 	unsigned progress : 1,

@@ -165,6 +167,9 @@ static int set_option(const char *name, const char *value)
 	} else if (!strcmp(name, "no-haves")) {
 		options.no_haves = 1;
 		return 0;
+	} else if (!strcmp(name, "filter")) {
+		options.partial_clone_filter = xstrdup(value);
+		return 0;
 	} else {
 		return 1 /* unsupported */;
 	}

@@ -834,6 +839,13 @@ static int fetch_git(struct discovery *heads,
 		argv_array_push(&args, "--from-promisor");
 	if (options.no_haves)
 		argv_array_push(&args, "--no-haves");
+	if (options.partial_clone_filter) {
+		struct list_objects_filter_options filter_options;
+		parse_list_objects_filter(&filter_options,
+					  options.partial_clone_filter);
+		argv_array_pushf(&args, "--%s=%s", CL_ARG__FILTER,
+				 filter_options.filter_spec);
+	}
 	argv_array_push(&args, url.buf);
 
 	for (i = 0; i < nr_heads; i++) {

index 6980072..bccc510 100644
@@ -861,6 +861,7 @@ extern int grafts_replace_parents;
 #define GIT_REPO_VERSION_READ 1
 extern int repository_format_precious_objects;
 extern char *repository_format_partial_clone;
+extern const char *core_partial_clone_filter_default;
 
 struct repository_format {
 	int version;

index adb7d7a..adeee04 100644
@@ -1241,6 +1241,11 @@ static int git_default_core_config(const char *var, const char *value)
 		return 0;
 	}
 
+	if (!strcmp(var, "core.partialclonefilter")) {
+		return git_config_string(&core_partial_clone_filter_default,
+					 var, value);
+	}
+
 	/* Add other config variables here and to Documentation/config.txt. */
 	return 0;
 }

index e52aab3..7537565 100644
@@ -28,6 +28,7 @@ int warn_on_object_refname_ambiguity = 1;
 int ref_paranoia = -1;
 int repository_format_precious_objects;
 char *repository_format_partial_clone;
+const char *core_partial_clone_filter_default;
 const char *git_commit_encoding;
 const char *git_log_output_encoding;
 const char *apply_default_whitespace;

121 lines not on this page · raw message

index dd7e5db..16884ca 100644
@@ -55,4 +55,10 @@ int opt_parse_list_objects_filter(const struct option *opt,
 	  N_("object filtering"), PARSE_OPT_NONEG, \
 	  opt_parse_list_objects_filter }
 
+void partial_clone_register(
+	const char *remote,
+	const struct list_objects_filter_options *filter_options);
+void partial_clone_get_default_filter_spec(
+	struct list_objects_filter_options *filter_options);
+
 #endif /* LIST_OBJECTS_FILTER_OPTIONS_H */

index 29d3807..e018aa3 100644
@@ -1047,9 +1047,11 @@ static struct transport *prepare_transport(struct remote *remote, int deepen)
 		set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, "yes");
 	if (update_shallow)
 		set_option(transport, TRANS_OPT_UPDATE_SHALLOW, "yes");
-	if (filter_options.choice)
+	if (filter_options.choice) {
 		set_option(transport, TRANS_OPT_LIST_OBJECTS_FILTER,
 			   filter_options.filter_spec);
+		set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
+	}
 	return transport;
 }
 

@@ -1287,6 +1289,59 @@ static int fetch_multiple(struct string_list *list)
 	return result;
 }
 
+static inline void fetch_one__setup_partial(struct remote *remote)
+{
+	int ppc, neq;
+
+	/* Do we have a prior partial clone/fetch? */
+	ppc = (repository_format_partial_clone &&
+	       *repository_format_partial_clone);
+
+	/*
+	 * If no prior partial clone/fetch and partial fetch was NOT
+	 * requested now, do a normal fetch.
+	 */
+	if (!ppc && !filter_options.choice)
+		return;
+
+	/*
+	 * If this is the FIRST partial fetch request, we enable partial
+	 * on this repo and remember the given filter-spec as the default
+	 * for subsequent fetches to this remote.
+	 */
+	if (!ppc && filter_options.choice) {
+		partial_clone_register(remote->name, &filter_options);
+		return;
+	}
+
+	/*
+	 * We are currently limited to only ONE promisor remote.  That is,
+	 * we only allow partial fetches back to the original partial clone
+	 * remote (or the first partial fetch remote).  Disallow explicit
+	 * partial fetches to a different remote.
+	 *
+	 * Normal (non-partial) fetch commands should still be allowed to
+	 * other remotes.
+	 */
+	neq = (strcmp(remote->name, repository_format_partial_clone));
+	if (neq && filter_options.choice)
+		die(_("unsupported partial-fetch to a different remote"));
+
+	if (neq && !filter_options.choice)
+		return;
+
+	/*
+	 * When fetching from the promisor remote, we either use the
+	 * explicitly given filter-spec or inherit the filter-spec from
+	 * the clone.
+	 */
+	if (filter_options.choice)
+		return;
+
+	partial_clone_get_default_filter_spec(&filter_options);
+	return;
+}
+
 static int fetch_one(struct remote *remote, int argc, const char **argv)
 {
 	static const char **refs = NULL;

@@ -1298,6 +1353,8 @@ static int fetch_one(struct remote *remote, int argc, const char **argv)
 		die(_("No remote repository specified.  Please, specify either a URL or a\n"
 		    "remote name from which new revisions should be fetched."));
 
+	fetch_one__setup_partial(remote);
+
 	gtransport = prepare_transport(remote, 1);
 
 	if (prune < 0) {

@@ -1348,6 +1405,8 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 
 	packet_trace_identity("fetch");
 
+	fetch_if_missing = 0;
+
 	/* Record the command line for the reflog */
 	strbuf_addstr(&default_rla, "fetch");
 	for (i = 1; i < argc; i++)

index f416b05..3a5bd67 100644
@@ -56,6 +56,8 @@ int check_connected(sha1_iterate_fn fn, void *cb_data,
 	argv_array_push(&rev_list.args,"rev-list");
 	argv_array_push(&rev_list.args, "--objects");
 	argv_array_push(&rev_list.args, "--stdin");
+	if (repository_format_partial_clone)
+		argv_array_push(&rev_list.args, "--exclude-promisor-objects");
 	argv_array_push(&rev_list.args, "--not");
 	argv_array_push(&rev_list.args, "--all");
 	argv_array_push(&rev_list.args, "--quiet");

index 0a8ac76..f519bd4 100644
@@ -889,6 +889,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	struct refspec *refspec;
 	const char *fetch_pattern;
 
+	fetch_if_missing = 0;
+
 	packet_trace_identity("clone");
 	argc = parse_options(argc, argv, prefix, builtin_clone_options,
 			     builtin_clone_usage, 0);

@@ -1109,11 +1111,13 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK,
 				     option_upload_pack);
 
-	if (filter_options.choice)
+	if (filter_options.choice) {
 		transport_set_option(transport, TRANS_OPT_LIST_OBJECTS_FILTER,
 				     filter_options.filter_spec);
+		transport_set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
+	}
 
-	if (transport->smart_options && !deepen)
+	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
 	refs = transport_get_remote_refs(transport);

@@ -1173,13 +1177,17 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	write_refspec_config(src_ref_prefix, our_head_points_at,
 			remote_head_points_at, &branch_top);
 
+	if (filter_options.choice)
+		partial_clone_register("origin", &filter_options);
+
 	if (is_local)
 		clone_local(path, git_dir);
 	else if (refs && complete_refs_before_fetch)
 		transport_fetch_refs(transport, mapped_refs);
 
 	update_remote_refs(refs, mapped_refs, remote_head_points_at,
-			   branch_top.buf, reflog_msg.buf, transport, !is_local);
+			   branch_top.buf, reflog_msg.buf, transport,
+			   !is_local && !filter_options.choice);
 
 	update_head(our_head_points_at, remote_head, reflog_msg.buf);
 

@@ -1200,6 +1208,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 
 	junk_mode = JUNK_LEAVE_REPO;
+	fetch_if_missing = 1;
 	err = checkout(submodule_progress);
 
 	strbuf_release(&reflog_msg);

index fc086fc..21b4dfa 100644
@@ -5,11 +5,10 @@
 #include "transport.h"
 #include "fetch-object.h"
 
-void fetch_object(const char *remote_name, const unsigned char *sha1)
+static void fetch_refs(const char *remote_name, struct ref *ref)
 {
 	struct remote *remote;
 	struct transport *transport;
-	struct ref *ref;
 	int original_fetch_if_missing = fetch_if_missing;
 
 	fetch_if_missing = 0;

@@ -18,10 +17,29 @@ void fetch_object(const char *remote_name, const unsigned char *sha1)
 		die(_("Remote with no URL"));
 	transport = transport_get(remote, remote->url[0]);
 
-	ref = alloc_ref(sha1_to_hex(sha1));
-	hashcpy(ref->old_oid.hash, sha1);
 	transport_set_option(transport, TRANS_OPT_FROM_PROMISOR, "1");
 	transport_set_option(transport, TRANS_OPT_NO_HAVES, "1");
 	transport_fetch_refs(transport, ref);
 	fetch_if_missing = original_fetch_if_missing;
 }
+
+void fetch_object(const char *remote_name, const unsigned char *sha1)
+{
+	struct ref *ref = alloc_ref(sha1_to_hex(sha1));
+	hashcpy(ref->old_oid.hash, sha1);
+	fetch_refs(remote_name, ref);
+}
+
+void fetch_objects(const char *remote_name, const struct oid_array *to_fetch)
+{
+	struct ref *ref = NULL;
+	int i;
+
+	for (i = 0; i < to_fetch->nr; i++) {
+		struct ref *new_ref = alloc_ref(oid_to_hex(&to_fetch->oid[i]));
+		oidcpy(&new_ref->old_oid, &to_fetch->oid[i]);
+		new_ref->next = ref;
+		ref = new_ref;
+	}
+	fetch_refs(remote_name, ref);
+}

index f371300..4b269d0 100644
@@ -1,6 +1,11 @@
 #ifndef FETCH_OBJECT_H
 #define FETCH_OBJECT_H
 
+#include "sha1-array.h"
+
 extern void fetch_object(const char *remote_name, const unsigned char *sha1);
 
+extern void fetch_objects(const char *remote_name,
+			  const struct oid_array *to_fetch);
+
 #endif

index 71b70cc..73a1cdb 100644
@@ -14,6 +14,7 @@
 #include "dir.h"
 #include "submodule.h"
 #include "submodule-config.h"
+#include "fetch-object.h"
 
 /*
  * Error messages expected by scripts out of plumbing commands such as

@@ -369,6 +370,27 @@ static int check_updates(struct unpack_trees_options *o)
 		load_gitmodules_file(index, &state);
 
 	enable_delayed_checkout(&state);
+	if (repository_format_partial_clone && o->update && !o->dry_run) {
+		/*
+		 * Prefetch the objects that are to be checked out in the loop
+		 * below.
+		 */
+		struct oid_array to_fetch = OID_ARRAY_INIT;
+		int fetch_if_missing_store = fetch_if_missing;
+		fetch_if_missing = 0;
+		for (i = 0; i < index->cache_nr; i++) {
+			struct cache_entry *ce = index->cache[i];
+			if ((ce->ce_flags & CE_UPDATE) &&
+			    !S_ISGITLINK(ce->ce_mode)) {
+				if (!has_object_file(&ce->oid))
+					oid_array_append(&to_fetch, &ce->oid);
+			}
+		}
+		if (to_fetch.nr)
+			fetch_objects(repository_format_partial_clone,
+				      &to_fetch);
+		fetch_if_missing = fetch_if_missing_store;
+	}
 	for (i = 0; i < index->cache_nr; i++) {
 		struct cache_entry *ce = index->cache[i];
 

index 2b04251..33a36d1 100644
@@ -717,6 +717,7 @@ static int everything_local(struct fetch_pack_args *args,
 {
 	struct ref *ref;
 	int retval;
+	int old_save_commit_buffer = save_commit_buffer;
 	timestamp_t cutoff = 0;
 
 	save_commit_buffer = 0;

@@ -784,6 +785,9 @@ static int everything_local(struct fetch_pack_args *args,
 		print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 			      ref->name);
 	}
+
+	save_commit_buffer = old_save_commit_buffer;
+
 	return retval;
 }