handle number-indexed lua maps in safe_index

docs/changelog.txt

@@ -74,6 +74,7 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 - Lua wrappers for functions reverse-engineered from ambushing unit code: ``isHidden(unit)``, ``isFortControlled(unit)``, ``getOuterContainerRef(unit)``, ``getOuterContainerRef(item)``
 - ``dwarfmode.enterSidebarMode()``: passing ``df.ui_sidebar_mode.DesignateMine`` now always results in you entering ``DesignateMine`` mode and not ``DesignateChopTrees``, even when you looking at the surface where the default designation mode is ``DesignateChopTrees``
 - New string class function: ``string:escape_pattern()`` escapes regex special characters within a string
+- ``safe_index`` now properly handles lua sparse tables that are indexed by numbers
 
 # 0.47.05-r4
 

library/lua/dfhack.lua

@@ -372,7 +372,9 @@ function safe_index(obj,idx,...)
     if obj == nil or idx == nil then
         return nil
     end
-    if type(idx) == 'number' and (idx < 0 or idx >= #obj) then
+    if type(idx) == 'number' and
+            type(obj) == 'userdata' and -- this check is only relevant for c++
+            (idx < 0 or idx >= #obj) then
         return nil
     end
     obj = obj[idx]