add automatic fixing of DF beta-specific caravan crash bug

data/init/onLoad.default.init

@@ -3,3 +3,5 @@
 # Please do not edit this file directly. It will be overwritten with new
 # defaults when you update DFHack. Instead, add your configuration to
 # dfhack-config/init/onLoad.init
+
+lua require('quickfix').set_entity_race_references()

library/lua/quickfix.lua

@@ -0,0 +1,30 @@
+-- short-term urgent bugfixes
+
+local _ENV = mkmodule("quickfix")
+
+local function get_dwarf_race()
+    for k,v in ipairs(df.global.world.raws.creatures.all) do
+        -- dwarves are always the first entity race
+        if v.flags.OCCURS_AS_ENTITY_RACE then return k end
+    end
+end
+
+-- entities can send caravans, and if the race is -1, then DF crashes
+-- called from onLoad.default.init
+function set_entity_race_references()
+    local race = get_dwarf_race()
+    if not race then
+        return
+    end
+
+    local count = 0
+    for _,v in ipairs(df.global.world.entities.all) do
+        if v.race == -1 then
+            count = count + 1
+            v.race = race
+        end
+    end
+    print(('quickfix: fixed %d unset entity race reference(s)'):format(count))
+end
+
+return _ENV