Lua error reporting

lua_error_reporting.diff

diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index d0e04bf..002c8b2 100644
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -10,6 +10,21 @@ core.register_item_raw = nil
 local register_alias_raw = core.register_alias_raw
 core.register_alias_raw = nil
 
+local function make_func_safe(func)
+       return function(...)
+               local arg = {...}
+               local worked, result = xpcall(function () return func(unpack(arg)) end,
+                       function(err)
+                               return debug.traceback(err, 1)
+                       end)
+               if worked then
+                       return result
+               else
+                       print(result)
+                       assert(false) -- still error, so that we can be sure we fail
+               end
+       end
+end
+
 --
 -- Item / entity / ABM registration functions
 --
@@ -154,6 +169,11 @@ function core.register_item(name, itemdef)
        -- Disable all further modifications
        getmetatable(itemdef).__newindex = {}
 
+       for idx, obj in pairs(itemdef) do
+               if type(obj) == "function" then
+                       itemdef[idx] = make_func_safe(obj)
+               end
+       end
        --core.log("Registering item: " .. itemdef.name)