ssh: 'simple' variant does not support -4/-6

If the user passes -4/--ipv4 or -6/--ipv6 to "git fetch" or "git push"
and the ssh command configured with GIT_SSH does not support such a
setting, error out instead of ignoring the option and continuing.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

connect.c

@@ -938,12 +938,31 @@ static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 				 get_protocol_version_config());
 	}
 
-	if (variant != VARIANT_SIMPLE) {
-		if (flags & CONNECT_IPV4)
+	if (flags & CONNECT_IPV4) {
+		switch (variant) {
+		case VARIANT_AUTO:
+			BUG("VARIANT_AUTO passed to push_ssh_options");
+		case VARIANT_SIMPLE:
+			die("ssh variant 'simple' does not support -4");
+		case VARIANT_SSH:
+		case VARIANT_PLINK:
+		case VARIANT_PUTTY:
+		case VARIANT_TORTOISEPLINK:
 			argv_array_push(args, "-4");
-		else if (flags & CONNECT_IPV6)
+		}
+	} else if (flags & CONNECT_IPV6) {
+		switch (variant) {
+		case VARIANT_AUTO:
+			BUG("VARIANT_AUTO passed to push_ssh_options");
+		case VARIANT_SIMPLE:
+			die("ssh variant 'simple' does not support -6");
+		case VARIANT_SSH:
+		case VARIANT_PLINK:
+		case VARIANT_PUTTY:
+		case VARIANT_TORTOISEPLINK:
 			argv_array_push(args, "-6");
 		}
+	}
 
 	if (variant == VARIANT_TORTOISEPLINK)
 		argv_array_push(args, "-batch");

t/t5601-clone.sh

@@ -364,9 +364,10 @@ test_expect_success 'OpenSSH variant passes -4' '
 	expect_ssh "-4 -p 123" myhost src
 '
 
-test_expect_success 'variant can be overriden' '
-	git -c ssh.variant=simple clone -4 "[myhost:123]:src" ssh-simple-clone &&
-	expect_ssh myhost src
+test_expect_success 'variant can be overridden' '
+	copy_ssh_wrapper_as "$TRASH_DIRECTORY/putty" &&
+	git -c ssh.variant=putty clone -4 "[myhost:123]:src" ssh-putty-clone &&
+	expect_ssh "-4 -P 123" myhost src
 '
 
 test_expect_success 'variant=auto picks based on basename' '
@@ -375,10 +376,9 @@ test_expect_success 'variant=auto picks based on basename' '
 	expect_ssh "-4 -P 123" myhost src
 '
 
-test_expect_success 'simple is treated as simple' '
+test_expect_success 'simple does not support -4/-6' '
 	copy_ssh_wrapper_as "$TRASH_DIRECTORY/simple" &&
-	git clone -4 "[myhost:123]:src" ssh-bracket-clone-simple &&
-	expect_ssh myhost src
+	test_must_fail git clone -4 "[myhost:123]:src" ssh-bracket-clone-simple
 '
 
 test_expect_success 'uplink is treated as simple' '