sol::no_constructor errors are incorrect/don't match the docs

[squeek502]

From the docs:

{anything}, sol::no_constructor

• {anything} should probably be "new", which will specifically block its creation and give a proper warning if someone calls new (otherwise it will just give a nil value error)

The errors that actually occur:

-------------------------------------------------------------------------------
no_constructor usage
  regular method 1
-------------------------------------------------------------------------------
..\no_constructor.cpp(11)
...............................................................................

..\no_constructor.cpp(16): FAILED:
  REQUIRE_NOTHROW( lua.script("a = thing.new()") )
due to unexpected exception with message:
  lua: error: caught (...) exception

-------------------------------------------------------------------------------
no_constructor usage
  regular method 2
-------------------------------------------------------------------------------
..\no_constructor.cpp(19)
...............................................................................

..\no_constructor.cpp(24): FAILED:
  REQUIRE_NOTHROW( lua.script("a = thing.new()") )
due to unexpected exception with message:
  lua: error: caught (...) exception

-------------------------------------------------------------------------------
no_constructor usage
  simple method 1
-------------------------------------------------------------------------------
..\no_constructor.cpp(27)
...............................................................................

..\no_constructor.cpp(32): FAILED:
  REQUIRE_NOTHROW( lua.script("a = thing.new()") )
due to unexpected exception with message:
  lua: error: [string "a = thing.new()"]:1: attempt to call field 'new' (a
  userdata value)

-------------------------------------------------------------------------------
no_constructor usage
  simple method 2
-------------------------------------------------------------------------------
..\no_constructor.cpp(35)
...............................................................................

..\no_constructor.cpp(40): FAILED:
  REQUIRE_NOTHROW( lua.script("a = thing.new()") )
due to unexpected exception with message:
  lua: error: [string "a = thing.new()"]:1: attempt to call field 'new' (a
  userdata value)

The test case (note: will fail even with proper error messages, this is just to see what the error messages look like; the test will need to look different to test that the errors are correct):

TEST_CASE("no_constructor usage")
{
	struct thing {};

	sol::state lua;
	lua.open_libraries(sol::lib::base);

	SECTION("regular method 1")
	{
		lua.new_usertype<thing>("thing",
			sol::meta_function::construct, sol::no_constructor
		);
		REQUIRE_NOTHROW(lua.script("a = thing.new()"));
	}

	SECTION("regular method 2")
	{
		lua.new_usertype<thing>("thing",
			"new", sol::no_constructor
		);
		REQUIRE_NOTHROW(lua.script("a = thing.new()"));
	}

	SECTION("simple method 1")
	{
		lua.new_simple_usertype<thing>("thing",
			sol::meta_function::construct, sol::no_constructor
		);
		REQUIRE_NOTHROW(lua.script("a = thing.new()"));
	}

	SECTION("simple method 2")
	{
		lua.new_simple_usertype<thing>("thing",
			"new", sol::no_constructor
		);
		REQUIRE_NOTHROW(lua.script("a = thing.new()"));
	}
}

[ThePhD]

I get proper errors for the first 2, but not the second 2. I'll fix that and update the docs.

I don't know why you're getting a lua: error: caught (...) exception. It sounds like you might be using LuaJIT, and the trampoline might be gagging the real error.

[ThePhD]

Fixed: https://github.com/ThePhD/sol2/releases/tag/v2.15.9

[squeek502]

Thanks for the fix, I'm still getting the ... exception for regular usertypes for some reason. I'm using standard Lua 5.1.5 compiled as C++ with SOL_USING_CXX_LUA and the MSVC14 compiler. If you'd like to investigate why that is happening any further, then let me know if there's any information you need from me.