Make some fields on objects/map objects immutable

src/api/Fs.lua

@@ -17,7 +17,7 @@ function Fs.open(filepath, mode)
    -- love.File:open() does not support "rb"
    mode = mode:gsub("b$", "")
 
-   if not fs.is_absolute(filepath) then
+   if fs.get_global_working_directory() and not fs.is_absolute(filepath) then
       filepath = fs.join(Fs.get_working_directory(), filepath)
    end
 

src/api/IMapObject.lua

@@ -9,17 +9,19 @@ local Log = require("api.Log")
 local IMapObject  = class.interface("IMapObject",
                              {
                                 uid = "number",
-                                x = "number",
-                                y = "number",
                                 produce_memory = "function"
                              },
                              {IOwned, IObject})
 
 function IMapObject:init()
    IObject.init(self)
 
-   self.x = 0
-   self.y = 0
+   -- We make `x` and `y` immutable using `object.__newindex`, to force their
+   -- update through IMapObject:set_pos(x, y). This is so positional indexing
+   -- structures can get updated properly.
+   local mt = getmetatable(self)
+   mt.x = 0
+   mt.y = 0
 end
 
 function IMapObject:refresh_cell_on_map()

src/api/IOwned.lua

@@ -2,7 +2,7 @@ local ILocation = require("api.ILocation")
 
 local IOwned = class.interface("IOwned",
                          {
-                            location = { type = ILocation, optional = true },
+                            -- location = { type = ILocation, optional = true },
                             _parent = { type = ILocation, optional = true }
                          })
 

src/api/MapObject.lua

@@ -2,6 +2,7 @@ local object = require("internal.object")
 local ILocation = require("api.ILocation")
 local pool = require("internal.pool")
 local IOwned = require("api.IOwned")
+local IMapObject = require("api.IMapObject")
 
 local Event = require("api.Event")
 local Object = require("api.Object")
@@ -17,7 +18,9 @@ function MapObject.generate_from(_type, id, uid_tracker)
    -- params.no_pre_build = true
    local obj = Object.generate_from(_type, id)
 
-   rawset(obj, "uid", uid)
+   local mt = getmetatable(obj)
+   assert(mt.__id == "object")
+   rawset(mt, "uid", uid)
 
    -- class.assert_is_an(IMapObject, data)
 
@@ -34,7 +37,9 @@ function MapObject.generate(proto, uid_tracker)
    -- params.no_pre_build = true
    local obj = Object.generate(proto)
 
-   rawset(obj, "uid", uid)
+   local mt = getmetatable(obj)
+   assert(mt.__id == "object")
+   rawset(mt, "uid", uid)
 
    -- class.assert_is_an(IMapObject, obj)
 
@@ -95,12 +100,7 @@ function MapObject.clone_base(obj, owned)
 end
 
 function MapObject.is_map_object(t)
-   if type(t) ~= "table" then
-      return false
-   end
-
-   local mt = getmetatable(t)
-   return mt and mt.__index == object.__index and type(t.x) == "number" and type(t.y) == "number" or false
+   return class.is_an(IMapObject, t) or false
 end
 
 -- NOTE: We could have an interface for classes that need special cloning logic.
@@ -159,7 +159,32 @@ local function cycle_aware_copy(t, cache, uids, first, opts)
    if t.__class and class.is_class_or_interface(mt) then
       res.__class = mt
    end
-   setmetatable(res,mt)
+   if mt then
+      local is_object = mt.__id == "object"
+      if is_object then
+         local new_mt = {}
+
+         -- see `object.deserialize()`
+         new_mt.__id = mt.__id
+         new_mt.__index = object.__index
+         new_mt.__newindex = object.__newindex
+         new_mt.__iface = mt.__iface
+         new_mt.__tostring = object.__tostring
+         new_mt.__inspect = object.__inspect
+
+         -- immutable state
+         new_mt.uid = nil
+         new_mt.x = mt.x
+         new_mt.y = mt.y
+         new_mt.location = nil
+         new_mt._id = mt._id
+         new_mt._type = mt._type
+
+         setmetatable(res,new_mt)
+      else
+         setmetatable(res,mt)
+      end
+   end
 
    return res
 end
@@ -179,13 +204,13 @@ function MapObject.clone(obj, owned, uid_tracker, cache, opts)
 
    local new_object = cycle_aware_copy(obj, cache or {}, uid_tracker, true, opts)
 
-   if not preserve_uid then
-      new_object.uid = uid_tracker:get_next_and_increment()
+   local mt = getmetatable(new_object)
+   if preserve_uid then
+      mt.uid = obj.uid
+   else
+      mt.uid = uid_tracker:get_next_and_increment()
    end
 
-   local mt = getmetatable(obj)
-   setmetatable(new_object, mt)
-
    local location = obj:get_location()
    if owned and class.is_an("api.IMapObject", obj) and class.is_an("api.ILocation", location) then
       assert(not preserve_uid, "Cannot preserve UID for owned object")

src/api/chara/IChara.lua

@@ -108,10 +108,14 @@ function IChara:build()
    self.target = nil
 
    -- HACK fallback now to prevent errors. Races should always declare an image,
-   -- but they might not in error. However, `image` should still be nil during
-   -- creation and not have any fallback, in order to potentially override it
-   -- with the male/female image defaults from the character's race.
-   self.image = self.image or "elona.chara_race_slime"
+   -- but they might not in error. However, `image` should still be some special
+   -- fallback (base.default) during creation, in order to potentially override
+   -- it with the male/female image defaults from the character's race.
+   --
+   -- And we can't set a fallback inside `data:add_type {}` because the race's
+   -- properties will not overwrite any properties that already exist on the
+   -- object (even if image = "base.default"), so it has to have a nil fallback.
+   self.image = self.image or "base.default"
 
    self:reset_ai()
 

src/api/test/Assert.lua

@@ -32,7 +32,7 @@ function Assert.lt(expected, actual)
    end
 end
 
-function Assert.error(f, err_match, ...)
+function Assert.throws_error(f, err_match, ...)
    local ok, err = pcall(f, ...)
    if ok then
       error("expected error, but was successful")

src/game/field_logic.lua

@@ -53,7 +53,7 @@ function field_logic.quickstart()
    -- We will want to act as if the character making GUI is active, because that
    -- will force the player's equipment to be generated uncursed.
    chara_make.set_is_active_override(true)
-   local ok, err = pcall(function()
+   local ok, err = xpcall(function()
          local me = Chara.create(config.base.quickstart_chara_id, nil, nil, {ownerless=true})
          me:emit("base.on_finalize_player")
          me:emit("base.on_initialize_player")
@@ -65,7 +65,7 @@ function field_logic.quickstart()
          Skill.apply_class_params(me, me.class)
 
          field_logic.setup_new_game(me)
-   end)
+   end, debug.traceback)
    chara_make.set_is_active_override(false)
 
    if not ok then

src/internal/data/fallbacks.lua

@@ -11,6 +11,13 @@ data:add {
    image = "mod/base/graphic/floor.png"
 }
 
+data:add {
+   _type = "base.chip",
+   _id = "default",
+
+   image = "mod/base/graphic/blank.png"
+}
+
 data:add {
    _type = "base.chara",
    _id = "player",