fix require() wrapper to return all values returned by original require()

2 files changed, 13 insertions, 17 deletions

diff --git a/src/macros_and_utils.h b/src/macros_and_utils.h
index ae3a6c9..dba0010 100644
--- a/src/macros_and_utils.h
+++ b/src/macros_and_utils.h
@@ -60,7 +60,7 @@ extern char const* debugspew_indent;
                 int const L##_oldtop = 0
 
 #define STACK_MID( L, change) \
-                do \
+                do if( change != LUA_MULTRET) \
                 { \
                         int stack_check_a = lua_gettop( L) - L##_oldtop; \
                         int stack_check_b = (change); \
diff --git a/src/state.c b/src/state.c
index cbbc0d8..81371b7 100644
--- a/src/state.c
+++ b/src/state.c
@@ -51,7 +51,7 @@ THE SOFTWARE.
 */
 
 //---
-// [val]= new_require( ... )
+// [val,...]= new_require( ... )
 //
 // Call 'old_require' but only one lane at a time.
 //
@@ -59,36 +59,32 @@ THE SOFTWARE.
 //
 static int luaG_new_require( lua_State* L)
 {
-        int rc, i;
-        int args = lua_gettop( L);
+        int rc;
+        int const args = lua_gettop( L);                                    // args
         Universe* U = universe_get( L);
         //char const* modname = luaL_checkstring( L, 1);
 
-        STACK_GROW( L, args + 1);
-        STACK_CHECK( L, 0);
+        STACK_GROW( L, 1);
 
-        lua_pushvalue( L, lua_upvalueindex( 1));
-        for( i = 1; i <= args; ++ i)
-        {
-                lua_pushvalue( L, i);
-        }
+        lua_pushvalue( L, lua_upvalueindex( 1));                            // args require
+        lua_insert( L, 1);                                                  // require args
 
         // Using 'lua_pcall()' to catch errors; otherwise a failing 'require' would
         // leave us locked, blocking any future 'require' calls from other lanes.
-        //
+        
         MUTEX_LOCK( &U->require_cs);
-        rc = lua_pcall( L, args, 1 /*retvals*/, 0 /*errfunc*/ );
+        // starting with Lua 5.4, require may return a second optional value, so we need LUA_MULTRET
+        rc = lua_pcall( L, args, LUA_MULTRET, 0 /*errfunc*/ ); // err|result(s)
         MUTEX_UNLOCK( &U->require_cs);
 
         // the required module (or an error message) is left on the stack as returned value by original require function
-        STACK_END( L, 1);
 
         if( rc != LUA_OK) // LUA_ERRRUN / LUA_ERRMEM ?
         {
-                return lua_error( L);   // error message already at [-1]
+                return lua_error( L);
         }
-
-        return 1;
+        // should be 1 for Lua <= 5.3, 1 or 2 starting with Lua 5.4
+        return lua_gettop(L);                                           // result(s)
 }
 
 /*