[PATCH v3 3/3] builtin/fetch: die on --negotiate-only and --recurse-submodules

[Glen Choo <chooglen@google.com>]

The previous commit ignores the value of --recurse-submodules if
--negotiate-only is given. Since non "no" values of --recurse-submodules
are not supported with --negotiate-only, make cmd_fetch() check for
this invalid combination and die.

This is unlikely to affect internal usage of --negotiate-only, but it
may be helpful for users. We may also want to discourage users from
using --negotiate-only altogether because it was not intended for them.

Signed-off-by: Glen Choo <chooglen@google.com>
---
 Documentation/fetch-options.txt |  1 +
 builtin/fetch.c                 | 24 ++++++++++++++++++------
 t/t5702-protocol-v2.sh          | 17 +++++++++++++++++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index e967ff1874..81a100d593 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -71,6 +71,7 @@ configuration variables documented in linkgit:git-config[1], and the
 	ancestors of the provided `--negotiation-tip=*` arguments,
 	which we have in common with the server.
 +
+This is incompatible with `--recurse-submodules[=yes|on-demand]`.
 Internally this is used to implement the `push.negotiate` option, see
 linkgit:git-config[1].
 
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 883bb1b10c..54f970130e 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -75,6 +75,7 @@ static struct transport *gtransport;
 static struct transport *gsecondary;
 static const char *submodule_prefix = "";
 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
+static int recurse_submodules_explicit = RECURSE_SUBMODULES_DEFAULT;
 static int recurse_submodules_default = RECURSE_SUBMODULES_ON_DEMAND;
 static int shown_url = 0;
 static struct refspec refmap = REFSPEC_INIT_FETCH;
@@ -166,7 +167,7 @@ static struct option builtin_fetch_options[] = {
 		 N_("prune remote-tracking branches no longer on remote")),
 	OPT_BOOL('P', "prune-tags", &prune_tags,
 		 N_("prune local tags no longer on remote and clobber changed tags")),
-	OPT_CALLBACK_F(0, "recurse-submodules", &recurse_submodules, N_("on-demand"),
+	OPT_CALLBACK_F(0, "recurse-submodules", &recurse_submodules_explicit, N_("on-demand"),
 		    N_("control recursive fetching of submodules"),
 		    PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
 	OPT_BOOL(0, "dry-run", &dry_run,
@@ -1997,12 +1998,23 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix,
 			     builtin_fetch_options, builtin_fetch_usage, 0);
 
+	if (recurse_submodules_explicit != RECURSE_SUBMODULES_DEFAULT)
+		recurse_submodules = recurse_submodules_explicit;
+
 	if (negotiate_only) {
-		/*
-		 * --negotiate-only should never recurse into
-		 * submodules, so there is no need to read .gitmodules.
-		 */
-		recurse_submodules = RECURSE_SUBMODULES_OFF;
+		switch (recurse_submodules_explicit) {
+		case RECURSE_SUBMODULES_OFF:
+		case RECURSE_SUBMODULES_DEFAULT: {
+			/*
+			 * --negotiate-only should never recurse into
+			 * submodules, so there is no need to read .gitmodules.
+			 */
+			recurse_submodules = RECURSE_SUBMODULES_OFF;
+			break;
+		}
+		default:
+			die(_("--negotiate-only and --recurse-submodules cannot be used together"));
+		}
 	}
 
 	if (recurse_submodules != RECURSE_SUBMODULES_OFF) {
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index d527cf6c49..d099c46499 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -628,6 +628,23 @@ test_expect_success 'usage: --negotiate-only without --negotiation-tip' '
 	test_cmp err.expect err.actual
 '
 
+test_expect_success 'usage: --negotiate-only with --recurse-submodules' '
+	SERVER="server" &&
+	URI="file://$(pwd)/server" &&
+
+	setup_negotiate_only "$SERVER" "$URI" &&
+
+	cat >err.expect <<-\EOF &&
+	fatal: --negotiate-only and --recurse-submodules cannot be used together
+	EOF
+
+	test_must_fail git -c protocol.version=2 -C client fetch \
+		--negotiate-only \
+		--recurse-submodules \
+		origin 2>err.actual &&
+	test_cmp err.expect err.actual
+'
+
 test_expect_success 'file:// --negotiate-only' '
 	SERVER="server" &&
 	URI="file://$(pwd)/server" &&
-- 
2.33.GIT