sd-bus: don't assert() on valid signatures

Right now sd_bus_message_skip() will abort execution if passed a
signature of the unary type "()". Regardless whether this should be
supported or not, we really must not abort. Drop the incorrect assertion
and add a test-case for this.

2 files changed, 7 insertions, 2 deletions

diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 18685be8ff..081f39d83b 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -4756,7 +4756,6 @@ _public_ int sd_bus_message_skip(sd_bus_message *m, const char *types) {
                         r = sd_bus_message_skip(m, s);
                         if (r < 0)
                                 return r;
-                        assert(r != 0);
 
                         r = sd_bus_message_exit_container(m);
                         if (r < 0)
diff --git a/src/libsystemd/sd-bus/test-bus-marshal.c b/src/libsystemd/sd-bus/test-bus-marshal.c
index 59deaea89f..b203707f27 100644
--- a/src/libsystemd/sd-bus/test-bus-marshal.c
+++ b/src/libsystemd/sd-bus/test-bus-marshal.c
@@ -134,6 +134,9 @@ int main(int argc, char *argv[]) {
         r = sd_bus_message_append(m, "y(ty)y(yt)y", 8, 777ULL, 7, 9, 77, 7777ULL, 10);
         assert_se(r >= 0);
 
+        r = sd_bus_message_append(m, "()");
+        assert_se(r >= 0);
+
         r = sd_bus_message_append(m, "ba(ss)", 255, 3, "aaa", "1", "bbb", "2", "ccc", "3");
         assert_se(r >= 0);
 
@@ -271,6 +274,9 @@ int main(int argc, char *argv[]) {
         assert_se(r > 0);
         assert_se(v == 10);
 
+        r = sd_bus_message_read(m, "()");
+        assert_se(r > 0);
+
         r = sd_bus_message_read(m, "ba(ss)", &boolean, 3, &x, &y, &a, &b, &c, &d);
         assert_se(r > 0);
         assert_se(boolean);
@@ -350,7 +356,7 @@ int main(int argc, char *argv[]) {
 
         assert_se(sd_bus_message_verify_type(m, 'a', "{yv}") > 0);
 
-        r = sd_bus_message_skip(m, "a{yv}y(ty)y(yt)y");
+        r = sd_bus_message_skip(m, "a{yv}y(ty)y(yt)y()");
         assert_se(r >= 0);
 
         assert_se(sd_bus_message_verify_type(m, 'b', NULL) > 0);