Merge branch 'sb/push-options'

"git push" learned to accept and pass extra options to the
receiving end so that hooks can read and react to them.

* sb/push-options:
  add a test for push options
  push: accept push options
  receive-pack: implement advertising and receiving push options
  push options: {pre,post}-receive hook learns about push options

13 files changed, 294 insertions, 23 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 8b1aee4b3b..4ae564b487 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2427,8 +2427,13 @@ rebase.instructionFormat
 
 receive.advertiseAtomic::
 	By default, git-receive-pack will advertise the atomic push
-	capability to its clients. If you don't want to this capability
-	to be advertised, set this variable to false.
+	capability to its clients. If you don't want to advertise this
+	capability, set this variable to false.
+
+receive.advertisePushOptions::
+	By default, git-receive-pack will advertise the push options
+	capability to its clients. If you don't want to advertise this
+	capability, set this variable to false.
 
 receive.autogc::
 	By default, git-receive-pack will run "git-gc --auto" after
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 93c3527f0c..ec514f6cd5 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -11,7 +11,7 @@ SYNOPSIS
 [verse]
 'git push' [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
 	   [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
-	   [-u | --set-upstream]
+	   [-u | --set-upstream] [--push-option=<string>]
 	   [--[no-]signed|--sign=(true|false|if-asked)]
 	   [--force-with-lease[=<refname>[:<expect>]]]
 	   [--no-verify] [<repository> [<refspec>...]]
@@ -156,6 +156,12 @@ already exists on the remote side.
 	Either all refs are updated, or on error, no refs are updated.
 	If the server does not support atomic pushes the push will fail.
 
+-o::
+--push-option::
+	Transmit the given string to the server, which passes them to
+	the pre-receive as well as the post-receive hook. The given string
+	must not contain a NUL or LF character.
+
 --receive-pack=<git-receive-pack>::
 --exec=<git-receive-pack>::
 	Path to the 'git-receive-pack' program on the remote
diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
index d82e912e55..9565dc3fda 100644
--- a/Documentation/githooks.txt
+++ b/Documentation/githooks.txt
@@ -247,6 +247,15 @@ Both standard output and standard error output are forwarded to
 'git send-pack' on the other end, so you can simply `echo` messages
 for the user.
 
+The number of push options given on the command line of
+`git push --push-option=...` can be read from the environment
+variable `GIT_PUSH_OPTION_COUNT`, and the options themselves are
+found in `GIT_PUSH_OPTION_0`, `GIT_PUSH_OPTION_1`,...
+If it is negotiated to not use the push options phase, the
+environment variables will not be set. If the client selects
+to use push options, but doesn't transmit any, the count variable
+will be set to zero, `GIT_PUSH_OPTION_COUNT=0`.
+
 [[update]]
 update
 ~~~~~~
@@ -322,6 +331,15 @@ a sample script `post-receive-email` provided in the `contrib/hooks`
 directory in Git distribution, which implements sending commit
 emails.
 
+The number of push options given on the command line of
+`git push --push-option=...` can be read from the environment
+variable `GIT_PUSH_OPTION_COUNT`, and the options themselves are
+found in `GIT_PUSH_OPTION_0`, `GIT_PUSH_OPTION_1`,...
+If it is negotiated to not use the push options phase, the
+environment variables will not be set. If the client selects
+to use push options, but doesn't transmit any, the count variable
+will be set to zero, `GIT_PUSH_OPTION_COUNT=0`.
+
 [[post-update]]
 post-update
 ~~~~~~~~~~~
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index 8b36343802..7a2ed30cfc 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -454,7 +454,8 @@ The reference discovery phase is done nearly the same way as it is in the
 fetching protocol. Each reference obj-id and name on the server is sent
 in packet-line format to the client, followed by a flush-pkt.  The only
 real difference is that the capability listing is different - the only
-possible values are 'report-status', 'delete-refs' and 'ofs-delta'.
+possible values are 'report-status', 'delete-refs', 'ofs-delta' and
+'push-options'.
 
 Reference Update Request and Packfile Transfer
 ----------------------------------------------
@@ -465,9 +466,10 @@ that it wants to update, it sends a line listing the obj-id currently on
 the server, the obj-id the client would like to update it to and the name
 of the reference.
 
-This list is followed by a flush-pkt and then the packfile that should
-contain all the objects that the server will need to complete the new
-references.
+This list is followed by a flush-pkt. Then the push options are transmitted
+one per packet followed by another flush-pkt. After that the packfile that
+should contain all the objects that the server will need to complete the new
+references will be sent.
 
 ----
   update-request    =  *shallow ( command-list | push-cert ) [packfile]
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt
index eaab6b4ac7..4c28d3a8ae 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/technical/protocol-capabilities.txt
@@ -253,6 +253,15 @@ atomic pushes. If the pushing client requests this capability, the server
 will update the refs in one atomic transaction. Either all refs are
 updated or none.
 
+push-options
+------------
+
+If the server sends the 'push-options' capability it is able to accept
+push options after the update commands have been sent, but before the
+packfile is streamed. If the pushing client requests this capability,
+the server will pass the options to the pre- and post- receive hooks
+that process this push request.
+
 allow-tip-sha1-in-want
 ----------------------
 
diff --git a/builtin/push.c b/builtin/push.c
index 4e9e4dbab2..3bb9d6b7e6 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -353,7 +353,8 @@ static int push_with_options(struct transport *transport, int flags)
 	return 1;
 }
 
-static int do_push(const char *repo, int flags)
+static int do_push(const char *repo, int flags,
+		   const struct string_list *push_options)
 {
 	int i, errs;
 	struct remote *remote = pushremote_get(repo);
@@ -376,6 +377,9 @@ static int do_push(const char *repo, int flags)
 	if (remote->mirror)
 		flags |= (TRANSPORT_PUSH_MIRROR|TRANSPORT_PUSH_FORCE);
 
+	if (push_options->nr)
+		flags |= TRANSPORT_PUSH_OPTIONS;
+
 	if ((flags & TRANSPORT_PUSH_ALL) && refspec) {
 		if (!strcmp(*refspec, "refs/tags/*"))
 			return error(_("--all and --tags are incompatible"));
@@ -406,13 +410,16 @@ static int do_push(const char *repo, int flags)
 		for (i = 0; i < url_nr; i++) {
 			struct transport *transport =
 				transport_get(remote, url[i]);
+			if (flags & TRANSPORT_PUSH_OPTIONS)
+				transport->push_options = push_options;
 			if (push_with_options(transport, flags))
 				errs++;
 		}
 	} else {
 		struct transport *transport =
 			transport_get(remote, NULL);
-
+		if (flags & TRANSPORT_PUSH_OPTIONS)
+			transport->push_options = push_options;
 		if (push_with_options(transport, flags))
 			errs++;
 	}
@@ -500,6 +507,9 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 	int push_cert = -1;
 	int rc;
 	const char *repo = NULL;	/* default repository */
+	static struct string_list push_options = STRING_LIST_INIT_DUP;
+	static struct string_list_item *item;
+
 	struct option options[] = {
 		OPT__VERBOSITY(&verbosity),
 		OPT_STRING( 0 , "repo", &repo, N_("repository"), N_("repository")),
@@ -533,6 +543,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		  0, "signed", &push_cert, "yes|no|if-asked", N_("GPG sign the push"),
 		  PARSE_OPT_OPTARG, option_parse_push_signed },
 		OPT_BIT(0, "atomic", &flags, N_("request atomic transaction on remote side"), TRANSPORT_PUSH_ATOMIC),
+		OPT_STRING_LIST('o', "push-option", &push_options, N_("server-specific"), N_("option to transmit")),
 		OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
 				TRANSPORT_FAMILY_IPV4),
 		OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
@@ -563,7 +574,11 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		set_refspecs(argv + 1, argc - 1, repo);
 	}
 
-	rc = do_push(repo, flags);
+	for_each_string_list_item(item, &push_options)
+		if (strchr(item->string, '\n'))
+			die(_("push options must not have new line characters"));
+
+	rc = do_push(repo, flags, &push_options);
 	if (rc == -1)
 		usage_with_options(push_usage, options);
 	else
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 15c323a7cd..3c9360aa6d 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -44,10 +44,12 @@ static struct strbuf fsck_msg_types = STRBUF_INIT;
 static int receive_unpack_limit = -1;
 static int transfer_unpack_limit = -1;
 static int advertise_atomic_push = 1;
+static int advertise_push_options;
 static int unpack_limit = 100;
 static int report_status;
 static int use_sideband;
 static int use_atomic;
+static int use_push_options;
 static int quiet;
 static int prefer_ofs_delta = 1;
 static int auto_update_server_info;
@@ -193,6 +195,11 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (strcmp(var, "receive.advertisepushoptions") == 0) {
+		advertise_push_options = git_config_bool(var, value);
+		return 0;
+	}
+
 	return git_default_config(var, value, cb);
 }
 
@@ -211,6 +218,8 @@ static void show_ref(const char *path, const unsigned char *sha1)
 			strbuf_addstr(&cap, " ofs-delta");
 		if (push_cert_nonce)
 			strbuf_addf(&cap, " push-cert=%s", push_cert_nonce);
+		if (advertise_push_options)
+			strbuf_addstr(&cap, " push-options");
 		strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
 		packet_write(1, "%s %s%c%s\n",
 			     sha1_to_hex(sha1), path, 0, cap.buf);
@@ -550,8 +559,16 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 	}
 }
 
+struct receive_hook_feed_state {
+	struct command *cmd;
+	int skip_broken;
+	struct strbuf buf;
+	const struct string_list *push_options;
+};
+
 typedef int (*feed_fn)(void *, const char **, size_t *);
-static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state)
+static int run_and_feed_hook(const char *hook_name, feed_fn feed,
+			     struct receive_hook_feed_state *feed_state)
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
 	struct async muxer;
@@ -567,6 +584,16 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
 	proc.argv = argv;
 	proc.in = -1;
 	proc.stdout_to_stderr = 1;
+	if (feed_state->push_options) {
+		int i;
+		for (i = 0; i < feed_state->push_options->nr; i++)
+			argv_array_pushf(&proc.env_array,
+				"GIT_PUSH_OPTION_%d=%s", i,
+				feed_state->push_options->items[i].string);
+		argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT=%d",
+				 feed_state->push_options->nr);
+	} else
+		argv_array_pushf(&proc.env_array, "GIT_PUSH_OPTION_COUNT");
 
 	if (use_sideband) {
 		memset(&muxer, 0, sizeof(muxer));
@@ -606,12 +633,6 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
 	return finish_command(&proc);
 }
 
-struct receive_hook_feed_state {
-	struct command *cmd;
-	int skip_broken;
-	struct strbuf buf;
-};
-
 static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
 {
 	struct receive_hook_feed_state *state = state_;
@@ -634,8 +655,10 @@ static int feed_receive_hook(void *state_, const char **bufp, size_t *sizep)
 	return 0;
 }
 
-static int run_receive_hook(struct command *commands, const char *hook_name,
-			    int skip_broken)
+static int run_receive_hook(struct command *commands,
+			    const char *hook_name,
+			    int skip_broken,
+			    const struct string_list *push_options)
 {
 	struct receive_hook_feed_state state;
 	int status;
@@ -646,6 +669,7 @@ static int run_receive_hook(struct command *commands, const char *hook_name,
 	if (feed_receive_hook(&state, NULL, NULL))
 		return 0;
 	state.cmd = commands;
+	state.push_options = push_options;
 	status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
 	strbuf_release(&state.buf);
 	return status;
@@ -1316,7 +1340,8 @@ cleanup:
 
 static void execute_commands(struct command *commands,
 			     const char *unpacker_error,
-			     struct shallow_info *si)
+			     struct shallow_info *si,
+			     const struct string_list *push_options)
 {
 	struct command *cmd;
 	unsigned char sha1[20];
@@ -1335,7 +1360,7 @@ static void execute_commands(struct command *commands,
 
 	reject_updates_to_hidden(commands);
 
-	if (run_receive_hook(commands, "pre-receive", 0)) {
+	if (run_receive_hook(commands, "pre-receive", 0, push_options)) {
 		for (cmd = commands; cmd; cmd = cmd->next) {
 			if (!cmd->error_string)
 				cmd->error_string = "pre-receive hook declined";
@@ -1439,6 +1464,9 @@ static struct command *read_head_info(struct sha1_array *shallow)
 			if (advertise_atomic_push
 			    && parse_feature_request(feature_list, "atomic"))
 				use_atomic = 1;
+			if (advertise_push_options
+			    && parse_feature_request(feature_list, "push-options"))
+				use_push_options = 1;
 		}
 
 		if (!strcmp(line, "push-cert")) {
@@ -1471,6 +1499,21 @@ static struct command *read_head_info(struct sha1_array *shallow)
 	return commands;
 }
 
+static void read_push_options(struct string_list *options)
+{
+	while (1) {
+		char *line;
+		int len;
+
+		line = packet_read_line(0, &len);
+
+		if (!line)
+			break;
+
+		string_list_append(options, line);
+	}
+}
+
 static const char *parse_pack_header(struct pack_header *hdr)
 {
 	switch (read_pack_header(0, hdr)) {
@@ -1756,6 +1799,10 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 
 	if ((commands = read_head_info(&shallow)) != NULL) {
 		const char *unpack_status = NULL;
+		struct string_list push_options = STRING_LIST_INIT_DUP;
+
+		if (use_push_options)
+			read_push_options(&push_options);
 
 		prepare_shallow_info(&si, &shallow);
 		if (!si.nr_ours && !si.nr_theirs)
@@ -1764,13 +1811,17 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 			unpack_status = unpack_with_sideband(&si);
 			update_shallow_info(commands, &si, &ref);
 		}
-		execute_commands(commands, unpack_status, &si);
+		execute_commands(commands, unpack_status, &si,
+				 &push_options);
 		if (pack_lockfile)
 			unlink_or_warn(pack_lockfile);
 		if (report_status)
 			report(commands, unpack_status);
-		run_receive_hook(commands, "post-receive", 1);
+		run_receive_hook(commands, "post-receive", 1,
+				 &push_options);
 		run_update_post_hook(commands);
+		if (push_options.nr)
+			string_list_clear(&push_options, 0);
 		if (auto_gc) {
 			const char *argv_gc_auto[] = {
 				"gc", "--auto", "--quiet", NULL,
diff --git a/send-pack.c b/send-pack.c
index 299d303848..3a842ac2d1 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -260,6 +260,7 @@ static int generate_push_cert(struct strbuf *req_buf,
 			      const char *push_cert_nonce)
 {
 	const struct ref *ref;
+	struct string_list_item *item;
 	char *signing_key = xstrdup(get_signing_key());
 	const char *cp, *np;
 	struct strbuf cert = STRBUF_INIT;
@@ -276,6 +277,9 @@ static int generate_push_cert(struct strbuf *req_buf,
 	}
 	if (push_cert_nonce[0])
 		strbuf_addf(&cert, "nonce %s\n", push_cert_nonce);
+	if (args->push_options)
+		for_each_string_list_item(item, args->push_options)
+			strbuf_addf(&cert, "push-option %s\n", item->string);
 	strbuf_addstr(&cert, "\n");
 
 	for (ref = remote_refs; ref; ref = ref->next) {
@@ -370,6 +374,8 @@ int send_pack(struct send_pack_args *args,
 	int agent_supported = 0;
 	int use_atomic = 0;
 	int atomic_supported = 0;
+	int use_push_options = 0;
+	int push_options_supported = 0;
 	unsigned cmds_sent = 0;
 	int ret;
 	struct async demux;
@@ -392,6 +398,8 @@ int send_pack(struct send_pack_args *args,
 		args->use_thin_pack = 0;
 	if (server_supports("atomic"))
 		atomic_supported = 1;
+	if (server_supports("push-options"))
+		push_options_supported = 1;
 
 	if (args->push_cert != SEND_PACK_PUSH_CERT_NEVER) {
 		int len;
@@ -418,6 +426,11 @@ int send_pack(struct send_pack_args *args,
 
 	use_atomic = atomic_supported && args->atomic;
 
+	if (args->push_options && !push_options_supported)
+		die(_("the receiving end does not support push options"));
+
+	use_push_options = push_options_supported && args->push_options;
+
 	if (status_report)
 		strbuf_addstr(&cap_buf, " report-status");
 	if (use_sideband)
@@ -426,6 +439,8 @@ int send_pack(struct send_pack_args *args,
 		strbuf_addstr(&cap_buf, " quiet");
 	if (use_atomic)
 		strbuf_addstr(&cap_buf, " atomic");
+	if (use_push_options)
+		strbuf_addstr(&cap_buf, " push-options");
 	if (agent_supported)
 		strbuf_addf(&cap_buf, " agent=%s", git_user_agent_sanitized());
 
@@ -512,6 +527,18 @@ int send_pack(struct send_pack_args *args,
 	strbuf_release(&req_buf);
 	strbuf_release(&cap_buf);
 
+	if (use_push_options) {
+		struct string_list_item *item;
+		struct strbuf sb = STRBUF_INIT;
+
+		for_each_string_list_item(item, args->push_options)
+			packet_buf_write(&sb, "%s", item->string);
+
+		write_or_die(out, sb.buf, sb.len);
+		packet_flush(out);
+		strbuf_release(&sb);
+	}
+
 	if (use_sideband && cmds_sent) {
 		memset(&demux, 0, sizeof(demux));
 		demux.proc = sideband_demux;
diff --git a/send-pack.h b/send-pack.h
index 57f222abcc..67fc40f4ec 100644
--- a/send-pack.h
+++ b/send-pack.h
@@ -1,6 +1,8 @@
 #ifndef SEND_PACK_H
 #define SEND_PACK_H
 
+#include "string-list.h"
+
 /* Possible values for push_cert field in send_pack_args. */
 #define SEND_PACK_PUSH_CERT_NEVER 0
 #define SEND_PACK_PUSH_CERT_IF_ASKED 1
@@ -21,6 +23,7 @@ struct send_pack_args {
 		push_cert:2,
 		stateless_rpc:1,
 		atomic:1;
+	const struct string_list *push_options;
 };
 
 struct option;
diff --git a/t/t5545-push-options.sh b/t/t5545-push-options.sh
new file mode 100755
index 0000000000..ea813b9383
--- /dev/null
+++ b/t/t5545-push-options.sh
@@ -0,0 +1,103 @@
+#!/bin/sh
+
+test_description='pushing to a repository using push options'
+
+. ./test-lib.sh
+
+mk_repo_pair () {
+	rm -rf workbench upstream &&
+	test_create_repo upstream &&
+	test_create_repo workbench &&
+	(
+		cd upstream &&
+		git config receive.denyCurrentBranch warn &&
+		mkdir -p .git/hooks &&
+		cat >.git/hooks/pre-receive <<-'EOF' &&
+		#!/bin/sh
+		if test -n "$GIT_PUSH_OPTION_COUNT"; then
+			i=0
+			>hooks/pre-receive.push_options
+			while test "$i" -lt "$GIT_PUSH_OPTION_COUNT"; do
+				eval "value=\$GIT_PUSH_OPTION_$i"
+				echo $value >>hooks/pre-receive.push_options
+				i=$((i + 1))
+			done
+		fi
+		EOF
+		chmod u+x .git/hooks/pre-receive
+
+		cat >.git/hooks/post-receive <<-'EOF' &&
+		#!/bin/sh
+		if test -n "$GIT_PUSH_OPTION_COUNT"; then
+			i=0
+			>hooks/post-receive.push_options
+			while test "$i" -lt "$GIT_PUSH_OPTION_COUNT"; do
+				eval "value=\$GIT_PUSH_OPTION_$i"
+				echo $value >>hooks/post-receive.push_options
+				i=$((i + 1))
+			done
+		fi
+		EOF
+		chmod u+x .git/hooks/post-receive
+	) &&
+	(
+		cd workbench &&
+		git remote add up ../upstream
+	)
+}
+
+# Compare the ref ($1) in upstream with a ref value from workbench ($2)
+# i.e. test_refs second HEAD@{2}
+test_refs () {
+	test $# = 2 &&
+	git -C upstream rev-parse --verify "$1" >expect &&
+	git -C workbench rev-parse --verify "$2" >actual &&
+	test_cmp expect actual
+}
+
+test_expect_success 'one push option works for a single branch' '
+	mk_repo_pair &&
+	git -C upstream config receive.advertisePushOptions true &&
+	(
+		cd workbench &&
+		test_commit one &&
+		git push --mirror up &&
+		test_commit two &&
+		git push --push-option=asdf up master
+	) &&
+	test_refs master master &&
+	echo "asdf" >expect &&
+	test_cmp expect upstream/.git/hooks/pre-receive.push_options &&
+	test_cmp expect upstream/.git/hooks/post-receive.push_options
+'
+
+test_expect_success 'push option denied by remote' '
+	mk_repo_pair &&
+	git -C upstream config receive.advertisePushOptions false &&
+	(
+		cd workbench &&
+		test_commit one &&
+		git push --mirror up &&
+		test_commit two &&
+		test_must_fail git push --push-option=asdf up master
+	) &&
+	test_refs master HEAD@{1}
+'
+
+test_expect_success 'two push options work' '
+	mk_repo_pair &&
+	git -C upstream config receive.advertisePushOptions true &&
+	(
+		cd workbench &&
+		test_commit one &&
+		git push --mirror up &&
+		test_commit two &&
+		git push --push-option=asdf --push-option="more structured text" up master
+	) &&
+	test_refs master master &&
+	printf "asdf\nmore structured text\n" >expect &&
+	test_cmp expect upstream/.git/hooks/pre-receive.push_options &&
+	test_cmp expect upstream/.git/hooks/post-receive.push_options
+'
+
+test_done
diff --git a/templates/hooks--pre-receive.sample b/templates/hooks--pre-receive.sample
new file mode 100644
index 0000000000..a1fd29ec14
--- /dev/null
+++ b/templates/hooks--pre-receive.sample
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# An example hook script to make use of push options.
+# The example simply echoes all push options that start with 'echoback='
+# and rejects all pushes when the "reject" push option is used.
+#
+# To enable this hook, rename this file to "pre-receive".
+
+if test -n "$GIT_PUSH_OPTION_COUNT"
+then
+	i=0
+	while test "$i" -lt "$GIT_PUSH_OPTION_COUNT"
+	do
+		eval "value=\$GIT_PUSH_OPTION_$i"
+		case "$value" in
+		echoback=*)
+			echo "echo from the pre-receive-hook: ${value#*=}" >&2
+			;;
+		reject)
+			exit 1
+		esac
+		i=$((i + 1))
+	done
+fi
diff --git a/transport.c b/transport.c
index b233e3ee5e..4ba48b0596 100644
--- a/transport.c
+++ b/transport.c
@@ -513,6 +513,7 @@ static int git_transport_push(struct transport *transport, struct ref *remote_re
 	args.dry_run = !!(flags & TRANSPORT_PUSH_DRY_RUN);
 	args.porcelain = !!(flags & TRANSPORT_PUSH_PORCELAIN);
 	args.atomic = !!(flags & TRANSPORT_PUSH_ATOMIC);
+	args.push_options = transport->push_options;
 	args.url = transport->url;
 
 	if (flags & TRANSPORT_PUSH_CERT_ALWAYS)
diff --git a/transport.h b/transport.h
index c68140892c..6fe3485325 100644
--- a/transport.h
+++ b/transport.h
@@ -48,6 +48,12 @@ struct transport {
 	 */
 	unsigned cloning : 1;
 
+	/*
+	 * These strings will be passed to the {pre, post}-receive hook,
+	 * on the remote side, if both sides support the push options capability.
+	 */
+	const struct string_list *push_options;
+
 	/**
 	 * Returns 0 if successful, positive if the option is not
 	 * recognized or is inapplicable, and negative if the option
@@ -134,6 +140,7 @@ struct transport {
 #define TRANSPORT_PUSH_CERT_ALWAYS 2048
 #define TRANSPORT_PUSH_CERT_IF_ASKED 4096
 #define TRANSPORT_PUSH_ATOMIC 8192
+#define TRANSPORT_PUSH_OPTIONS 16384
 
 #define TRANSPORT_SUMMARY_WIDTH (2 * DEFAULT_ABBREV + 3)
 #define TRANSPORT_SUMMARY(x) (int)(TRANSPORT_SUMMARY_WIDTH + strlen(x) - gettext_width(x)), (x)