3 files changed, 17 insertions, 4 deletions

diff --git a/CHANGES b/CHANGES
index fba1392..c730ae5 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,8 @@
 CHANGES:
 
+CHANGE 140: BGe 22-Nov-18
+   * Raise an error instead of crashing when attempting to transfer a non-deep full userdata
+
 CHANGE 139: BGe 21-Nov-18
    * more DEBUGSPEW
 
diff --git a/src/tools.c b/src/tools.c
index d358e96..b00cef5 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -1617,6 +1617,12 @@ static void inter_copy_keyvaluepair( Universe* U, lua_State* L2, uint_t L2_cache
                                 valPath = (char*) alloca( strlen( upName_) + 16 + 5);
                                 sprintf( valPath, "%s[U:%p]", upName_, key);
                         }
+                        else if( lua_type( L, key_i) == LUA_TBOOLEAN)
+                        {
+                                int key = lua_toboolean( L, key_i);
+                                valPath = (char*) alloca( strlen( upName_) + 7);
+                                sprintf( valPath, "%s[%s]", upName_, key ? "true" : "false");
+                        }
                 }
                 /*
                 * Contents of metatables are copied with cache checking;
@@ -1629,7 +1635,7 @@ static void inter_copy_keyvaluepair( Universe* U, lua_State* L2, uint_t L2_cache
                 }
                 else
                 {
-                        luaL_error( L, "Unable to copy over type '%s' (in %s)", luaL_typename( L, val_i), (vt == VT_NORMAL) ? "table" : "metatable");
+                        luaL_error( L, "Unable to copy %s entry '%s' because of value is of type '%s'", (vt == VT_NORMAL) ? "table" : "metatable", valPath, luaL_typename( L, val_i));
                 }
         }
 }
@@ -1740,6 +1746,7 @@ static bool_t inter_copy_one_( Universe* U, lua_State* L2, uint_t L2_cache_i, lu
                         if( lua_isnil( L, -1))
                         {
                                 lua_pop( L, 2);                                                      // ...
+                                ret = FALSE;
                         }
                         else
                         {
diff --git a/tests/lanes_as_upvalue.lua b/tests/lanes_as_upvalue.lua
index 7cc5e14..c1944b0 100644
--- a/tests/lanes_as_upvalue.lua
+++ b/tests/lanes_as_upvalue.lua
@@ -1,8 +1,11 @@
-local lanes = require "lanes".configure() -- with timers enabled
+local lanes = require "lanes".configure{ verbose_errors = true} -- with timers enabled
 
 local function foo()
         local lanes = lanes -- lanes as upvalue
 end
 
-local h = lanes.gen( "*", foo)()
-h:join()
+local g = lanes.gen( "*", foo)
+
+-- this should raise an error as lanes.timer_lane is a Lane (a non-deep full userdata)
+local res, err = pcall( g)
+print( "Generating lane yielded: ", tostring( res), tostring( err))