From e84cf66683156fdebed4e3ad335b03cc7dbc04a3 Mon Sep 17 00:00:00 2001
From: ThePhD <phdofthehouse@gmail.com>
Date: Sun, 25 Oct 2015 06:48:19 -0400
Subject: [PATCH] decay to std::string instead of  `char*`, as its both safer
 (protects against early stack pops) and is handled better by g++'s new
 std::string conversion constructors Make sure we're only using C++11 features
 (no decltype(auto))

---
 sol/function.hpp       | 42 +++++++++++++++++++++---------------------
 sol/function_types.hpp |  9 ++++++---
 sol/proxy.hpp          |  4 ++--
 tests.cpp              |  2 +-
 4 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/sol/function.hpp b/sol/function.hpp
index 0a9d1f10..bb6401d9 100644
--- a/sol/function.hpp
+++ b/sol/function.hpp
@@ -60,25 +60,25 @@ public:
     function_result& operator=(const function_result&) = default;
     function_result(function_result&& o) : L(o.L), index(o.index), returncount(o.returncount), error(o.error) {
         // Must be manual, otherwise destructor will screw us
-	   // return count being 0 is enough to keep things clean
-	   // but will be thorough
-	   o.L = nullptr;
-	   o.index = 0;
-	   o.returncount = 0;
-	   o.error = call_error::runtime;
+        // return count being 0 is enough to keep things clean
+        // but will be thorough
+        o.L = nullptr;
+        o.index = 0;
+        o.returncount = 0;
+        o.error = call_error::runtime;
     }
     function_result& operator=(function_result&& o) {
-	   L = o.L;
-	   index = o.index;
-	   returncount = o.returncount;
-	   error = o.error;
-	   // Must be manual, otherwise destructor will screw us
-	   // return count being 0 is enough to keep things clean
-	   // but will be thorough
-	   o.L = nullptr;
-	   o.index = 0;
-	   o.returncount = 0;
-	   o.error = call_error::runtime;
+        L = o.L;
+        index = o.index;
+        returncount = o.returncount;
+        error = o.error;
+        // Must be manual, otherwise destructor will screw us
+        // return count being 0 is enough to keep things clean
+        // but will be thorough
+        o.L = nullptr;
+        o.index = 0;
+        o.returncount = 0;
+        o.error = call_error::runtime;
     }
 
     bool valid() const {
@@ -91,8 +91,8 @@ public:
         return get(tr, tr);
     }
 
-    operator const char* () const {
-        return get<const char*>();
+    operator std::string() const {
+        return get<std::string>();
     }
 
     template<typename T, EnableIf<Not<std::is_same<Unqualified<T>, const char*>>, Not<std::is_same<Unqualified<T>, char>>, Not<std::is_same<Unqualified<T>, std::string>>, Not<std::is_same<Unqualified<T>, std::initializer_list<char>>>> = 0>
@@ -210,13 +210,13 @@ public:
 
     template<typename... Ret, typename... Args>
     auto operator()(types<Ret...>, Args&&... args) const 
-    -> decltype(call<Ret...>(std::forward<Args>(args)...)) {
+    -> decltype(invoke(types<Ret...>(), types<Ret...>(), 0, std::declval<handler&>())) {
         return call<Ret...>(std::forward<Args>(args)...);
     }
 
     template<typename... Ret, typename... Args>
     auto call(Args&&... args) const
-    -> decltype(invoke(types<Ret...>(), types<Ret...>(), 0, std::declval<handler>())) {
+    -> decltype(invoke(types<Ret...>(), types<Ret...>(), 0, std::declval<handler&>())) {
         handler h(error_handler);
         push();
         int pushcount = stack::push_args(state(), std::forward<Args>(args)...);
diff --git a/sol/function_types.hpp b/sol/function_types.hpp
index 747fcf48..88215587 100644
--- a/sol/function_types.hpp
+++ b/sol/function_types.hpp
@@ -168,7 +168,8 @@ struct static_function {
     template<typename... Ret, typename... Args>
     static int typed_call(types<Ret...>, types<Args...> ta, function_type* fx, lua_State* L) {
         typedef typename return_type<Ret...>::type return_type;
-        decltype(auto) r = stack::call(L, 0, types<return_type>(), ta, fx);
+	   typedef decltype(stack::call(L, 0, types<return_type>(), ta, fx)) ret_t;
+        ret_t r = stack::call(L, 0, types<return_type>(), ta, fx);
         int nargs = static_cast<int>(sizeof...(Args));
         lua_pop(L, nargs);
         return stack::push(L, std::forward<decltype(r)>(r));
@@ -392,7 +393,8 @@ struct member_function : public base_function {
 
     template<typename... Ret, typename... Args>
     int operator()(types<Ret...> tr, types<Args...> ta, lua_State* L) {
-        decltype(auto) r = stack::call(L, 0, tr, ta, fx);
+        typedef decltype(stack::call(L, 0, tr, ta, fx)) ret_t;
+        ret_t r = stack::call(L, 0, tr, ta, fx);
         int nargs = static_cast<int>(sizeof...(Args));
         lua_pop(L, nargs);
         return stack::push(L, std::forward<decltype(r)>(r));
@@ -458,7 +460,8 @@ struct usertype_function_core : public base_function {
 
     template<typename... Ret, typename... Args>
     int call(types<Ret...> tr, types<Args...> ta, lua_State* L) {
-        decltype(auto) r = stack::call(L, 0, tr, ta, fx);
+        typedef decltype(stack::call(L, 0, tr, ta, fx)) ret_t;
+        ret_t r = stack::call(L, 0, tr, ta, fx);
         int nargs = static_cast<int>(sizeof...(Args));
         lua_pop(L, nargs);
         int pushcount = push(L, std::forward<decltype(r)>(r));
diff --git a/sol/proxy.hpp b/sol/proxy.hpp
index 1a69dc57..fd78b30d 100644
--- a/sol/proxy.hpp
+++ b/sol/proxy.hpp
@@ -67,8 +67,8 @@ public:
         return tbl.template get<T>( key );
     }
 
-    operator const char* () const {
-        return get<const char*>();
+    operator std::string() const {
+        return get<std::string>();
     }
 
     template<typename T, EnableIf<Not<std::is_same<Unqualified<T>, const char*>>, Not<std::is_same<Unqualified<T>, char>>, Not<std::is_same<Unqualified<T>, std::string>>, Not<std::is_same<Unqualified<T>, std::initializer_list<char>>>> = 0>
diff --git a/tests.cpp b/tests.cpp
index 312037f5..3f62aa9a 100644
--- a/tests.cpp
+++ b/tests.cpp
@@ -1009,7 +1009,7 @@ TEST_CASE( "functions/sol::function_result", "Function result should be the beef
     // Some function; just using a lambda to be cheap
     auto doom = []() {
         // Bypasses handler function: puts information directly into lua error
-        throw std::exception( errormessage1 );
+        throw std::runtime_error( errormessage1 );
     };
     auto luadoom = [&lua]() {
         // Does not bypass error function, will call it