Compile-time check for listen() having a tls credentials argument

include/quic/endpoint.hpp

@@ -67,6 +67,11 @@ namespace oxen::quic
         template <typename... Opt>
         bool listen(Opt&&... opts)
         {
+
+            static_assert(
+                    (0 + ... + std::is_convertible_v<remove_cvref_t<Opt>, std::shared_ptr<TLSCreds>>) == 1,
+                    "Endpoint listen requires exactly one std::shared_ptr<TLSCreds> argument");
+
             std::promise<bool> p;
             auto f = p.get_future();
 

include/quic/utils.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <type_traits>
+
 #include "format.hpp"
 
 extern "C"
@@ -134,6 +136,10 @@ namespace oxen::quic
     template <template <typename...> class Class, typename... Us>
     inline constexpr bool is_instantiation<Class, Class<Us...>> = true;
 
+    // Backport of c++20 std::remove_cvref_t
+    template <typename T>
+    using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
+
     // Application error code we close with if the stream data handle throws
     inline constexpr uint64_t STREAM_ERROR_EXCEPTION = (1ULL << 62) - 2;
     // Application error code we close with if the datagram data handle throws

tests/001-handshake.cpp

@@ -50,7 +50,8 @@ namespace oxen::quic::test
             auto ep_notls = test_net.endpoint(default_addr);
             auto ep_tls = test_net.endpoint(local_addr);
 
-            REQUIRE_THROWS(ep_notls->listen());
+            // ep_notls->listen();  // Shouldn't compile if uncommented!
+            // ep_notls->listen(local_tls, local_tls);  // Nor this
             REQUIRE_NOTHROW(ep_tls->listen(local_tls));
         };
 
@@ -152,33 +153,17 @@ namespace oxen::quic::test
         opt::local_addr server_local{};
         opt::local_addr client_local{};
 
-        SECTION("Unsuccessful TLS handshake - No server TLS credentials")
-        {
-            auto server_endpoint = test_net.endpoint(server_local, server_established);
-            REQUIRE_THROWS(server_endpoint->listen());
-
-            opt::remote_addr client_remote{"127.0.0.1"s, server_endpoint->local().port()};
-
-            auto client_endpoint = test_net.endpoint(client_local, client_established);
-            auto conn_interface = client_endpoint->connect(client_remote, client_tls);
-
-            REQUIRE_FALSE(client_established.is_ready());
-        };
-
-        SECTION("Successful TLS handshake")
-        {
-            auto server_endpoint = test_net.endpoint(server_local, server_established);
-            REQUIRE(server_endpoint->listen(server_tls));
+        auto server_endpoint = test_net.endpoint(server_local, server_established);
+        REQUIRE(server_endpoint->listen(server_tls));
 
-            opt::remote_addr client_remote{"127.0.0.1"s, server_endpoint->local().port()};
+        opt::remote_addr client_remote{"127.0.0.1"s, server_endpoint->local().port()};
 
-            auto client_endpoint = test_net.endpoint(client_local, client_established);
-            auto conn_interface = client_endpoint->connect(client_remote, client_tls);
+        auto client_endpoint = test_net.endpoint(client_local, client_established);
+        auto conn_interface = client_endpoint->connect(client_remote, client_tls);
 
-            REQUIRE(client_established.wait_ready());
-            REQUIRE(server_established.wait_ready());
-            REQUIRE(client_established.get());
-            REQUIRE(server_established.get());
-        };
+        REQUIRE(client_established.wait_ready());
+        REQUIRE(server_established.wait_ready());
+        REQUIRE(client_established.get());
+        REQUIRE(server_established.get());
     };
 }  // namespace oxen::quic::test