fetch: add --negotiation-restrict option

The --negotiation-tip option to 'git fetch' and 'git pull' allows users
to specify that they want to focus negotiation on a small set of
references. This is a _restriction_ on the negotiation set, helping to
focus the negotiation when the ref count is high. However, it doesn't
allow for the ability to opportunistically select references beyond that
list.

This subtle detail that this is a 'maximum set' and not a 'minimum set'
is not immediately clear from the option name. This makes it more
complicated to add a new option that provides the complementary behavior
of a minimum set.

For now, create a new synonym option, --negotiation-restrict, that
behaves identically to --negotiation-tip. Update the documentation to
make it clear that this new name is the preferred option, but we keep
the old name for compatibility.

Update a few warning messages with the new option, but also make them
translatable with the option name inserted by formatting. At least one
of these messages will be reused later for a new option.

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

Author: derrickstolee

Documentation/fetch-options.adoc

@@ -49,6 +49,7 @@ the current repository has the same history as the source repository.
 	`.git/shallow`. This option updates `.git/shallow` and accepts such
 	refs.
 
+`--negotiation-restrict=(<commit>|<glob>)`::
 `--negotiation-tip=(<commit>|<glob>)`::
 	By default, Git will report, to the server, commits reachable
 	from all local refs to find common commits in an attempt to
@@ -58,6 +59,9 @@ the current repository has the same history as the source repository.
 	local ref is likely to have commits in common with the
 	upstream ref being fetched.
 +
+`--negotiation-restrict` is the preferred name for this option;
+`--negotiation-tip` is accepted as a synonym.
++
 This option may be specified more than once; if so, Git will report
 commits reachable from any of the given commits.
 +

builtin/fetch.c

@@ -1558,8 +1558,8 @@ static void add_negotiation_tips(struct git_transport_options *smart_options)
 		refs_for_each_ref_ext(get_main_ref_store(the_repository),
 				      add_oid, oids, &opts);
 		if (old_nr == oids->nr)
-			warning("ignoring --negotiation-tip=%s because it does not match any refs",
-				s);
+			warning(_("ignoring %s=%s because it does not match any refs"),
+				"--negotiation-restrict", s);
 	}
 	smart_options->negotiation_tips = oids;
 }
@@ -1599,7 +1599,8 @@ static struct transport *prepare_transport(struct remote *remote, int deepen,
 		if (transport->smart_options)
 			add_negotiation_tips(transport->smart_options);
 		else
-			warning("ignoring --negotiation-tip because the protocol does not support it");
+			warning(_("ignoring %s because the protocol does not support it"),
+				"--negotiation-restrict");
 	}
 	return transport;
 }
@@ -2567,6 +2568,8 @@ int cmd_fetch(int argc,
 		OPT_IPVERSION(&family),
 		OPT_STRING_LIST(0, "negotiation-tip", &negotiation_tip, N_("revision"),
 				N_("report that we have only objects reachable from this object")),
+		OPT_STRING_LIST(0, "negotiation-restrict", &negotiation_tip, N_("revision"),
+				N_("report that we have only objects reachable from this object")),
 		OPT_BOOL(0, "negotiate-only", &negotiate_only,
 			 N_("do not fetch a packfile; instead, print ancestors of negotiation tips")),
 		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
@@ -2657,7 +2660,7 @@ int cmd_fetch(int argc,
 	}
 
 	if (negotiate_only && !negotiation_tip.nr)
-		die(_("--negotiate-only needs one or more --negotiation-tip=*"));
+		die(_("--negotiate-only needs one or more --negotiation-restrict=*"));
 
 	if (deepen_relative) {
 		if (deepen_relative < 0)

builtin/pull.c

@@ -999,6 +999,9 @@ int cmd_pull(int argc,
 		OPT_PASSTHRU_ARGV(0, "negotiation-tip", &opt_fetch, N_("revision"),
 			N_("report that we have only objects reachable from this object"),
 			0),
+		OPT_PASSTHRU_ARGV(0, "negotiation-restrict", &opt_fetch, N_("revision"),
+			N_("report that we have only objects reachable from this object"),
+			0),
 		OPT_BOOL(0, "show-forced-updates", &opt_show_forced_updates,
 			 N_("check for forced-updates on all updated branches")),
 		OPT_PASSTHRU(0, "set-upstream", &set_upstream, NULL,

t/t5510-fetch.sh

@@ -1460,6 +1460,31 @@ EOF
 	test_cmp fatal-expect fatal-actual
 '
 
+test_expect_success '--negotiation-restrict limits "have" lines sent' '
+	setup_negotiation_tip server server 0 &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch \
+		--negotiation-restrict=alpha_1 --negotiation-restrict=beta_1 \
+		origin alpha_s beta_s &&
+	check_negotiation_tip
+'
+
+test_expect_success '--negotiation-restrict understands globs' '
+	setup_negotiation_tip server server 0 &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch \
+		--negotiation-restrict=*_1 \
+		origin alpha_s beta_s &&
+	check_negotiation_tip
+'
+
+test_expect_success '--negotiation-restrict and --negotiation-tip can be mixed' '
+	setup_negotiation_tip server server 0 &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch \
+		--negotiation-restrict=alpha_1 \
+		--negotiation-tip=beta_1 \
+		origin alpha_s beta_s &&
+	check_negotiation_tip
+'
+
 test_expect_success SYMLINKS 'clone does not get confused by a D/F conflict' '
 	git init df-conflict &&
 	(

t/t5702-protocol-v2.sh

@@ -869,14 +869,14 @@ setup_negotiate_only () {
 	test_commit -C client three
 }
 
-test_expect_success 'usage: --negotiate-only without --negotiation-tip' '
+test_expect_success 'usage: --negotiate-only without --negotiation-restrict' '
 	SERVER="server" &&
 	URI="file://$(pwd)/server" &&
 
 	setup_negotiate_only "$SERVER" "$URI" &&
 
 	cat >err.expect <<-\EOF &&
-	fatal: --negotiate-only needs one or more --negotiation-tip=*
+	fatal: --negotiate-only needs one or more --negotiation-restrict=*
 	EOF
 
 	test_must_fail git -c protocol.version=2 -C client fetch \