BugFix: moveable but not-default-constructible types as replies in sync.

There was a compilation error in the case when moveable but
not-default-constructible type is used as reply in sync interaction.

dev/so_5_extra/sync/pub.hpp

@@ -738,7 +738,10 @@ class request_reply_t final
 								typeid(request_reply_t).name() );
 					}
 
-				return *result;
+				if constexpr( is_reply_moveable )
+					return std::move(*result);
+				else
+					return *result;
 			}
 
 	public :

dev/test/so_5_extra/sync/moveable_only/main.cpp

@@ -36,12 +36,38 @@ static_assert( std::is_move_constructible_v<reply_t> &&
 static_assert( !std::is_copy_constructible_v<reply_t> &&
 		!std::is_copy_assignable_v<reply_t> );
 
+// reply2 is not default constructible.
+class reply2_t final
+	{
+		std::string m_value;
+
+	public :
+		reply2_t( std::string value ) : m_value{ std::move(value) } {}
+
+		reply2_t( const reply2_t & ) = delete;
+		reply2_t & operator=( const reply2_t & ) = delete;
+
+		reply2_t( reply2_t && ) = default;
+		reply2_t & operator=( reply2_t && ) = default;
+
+		const std::string &
+		value() const noexcept { return m_value; }
+	};
+
+struct triple_t final
+{
+	int m_v;
+};
+
 class service_t final : public so_5::agent_t
 	{
 	public :
 		service_t( context_t ctx ) : so_5::agent_t{ std::move(ctx) }
 			{
-				so_subscribe_self().event( &service_t::on_request );
+				so_subscribe_self()
+					.event( &service_t::on_request )
+					.event( &service_t::on_triple_request )
+					;
 			}
 
 	private :
@@ -50,12 +76,20 @@ class service_t final : public so_5::agent_t
 			{
 				cmd->make_reply( std::to_string(cmd->request() * 2) );
 			}
+
+		void
+		on_triple_request( sync_ns::request_mhood_t<triple_t, reply2_t> cmd )
+			{
+				cmd->make_reply( std::to_string(cmd->request().m_v * 3) );
+			}
 	};
 
 TEST_CASE( "simple shutdown on empty environment" )
 {
 	std::string result1;
 	std::string result2;
+	std::string result3;
+	std::string result4;
 
 	run_with_time_limit( [&] {
 			so_5::launch( [&](so_5::environment_t & env) {
@@ -69,12 +103,22 @@ TEST_CASE( "simple shutdown on empty environment" )
 						auto r2 = sync_ns::request_opt_reply<int, reply_t>( svc, 5s, 3 );
 						result2 = r2->value();
 
+						using my_triple_request =
+								sync_ns::request_reply_t<triple_t, reply2_t>;
+						auto r3 = my_triple_request::ask_value( svc, 5s, 4 );
+						result3 = r3.value();
+
+						auto r4 = my_triple_request::ask_opt_value( svc, 5s, 5 );
+						result4 = r4->value();
+
 						env.stop();
 					} );
 		},
 		5 );
 
 	REQUIRE( result1 == "4" );
 	REQUIRE( result2 == "6" );
+	REQUIRE( result3 == "12" );
+	REQUIRE( result4 == "15" );
 }