feat: anchor first checkpoint for cold restart

tests/integration/title_checkpoint_cold_start.lua

@@ -0,0 +1,155 @@
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+local phase, root = arg[1], arg[2]
+assert(phase == "capture" or phase == "resume", "phase must be capture or resume")
+assert(type(root) == "string" and root ~= "", "test needs a persistence root")
+
+local function quote(value)
+  return "'" .. tostring(value):gsub("'", "'\\''") .. "'"
+end
+
+local function full(path) return root .. "/" .. path end
+
+local fs = {}
+function fs.createDirectory(path)
+  return os.execute("mkdir -p " .. quote(full(path))) == 0
+end
+function fs.write(path, body)
+  local parent = path:match("^(.*)/[^/]+$")
+  if parent then assert(fs.createDirectory(parent)) end
+  local handle = assert(io.open(full(path), "wb"))
+  handle:write(body)
+  handle:close()
+  return true
+end
+function fs.read(path)
+  local handle = io.open(full(path), "rb")
+  if not handle then return nil end
+  local body = handle:read("*a")
+  handle:close()
+  return body
+end
+function fs.remove(path)
+  os.remove(full(path))
+  return true
+end
+function fs.getInfo(path)
+  if os.execute("test -d " .. quote(full(path))) == 0 then
+    return { type = "directory" }
+  end
+  local handle = io.open(full(path), "rb")
+  if handle then handle:close(); return { type = "file" } end
+  return nil
+end
+function fs.load(path)
+  local body = fs.read(path)
+  if not body then return nil, "no file: " .. path end
+  return load(body, "@" .. path)
+end
+function fs.getDirectoryItems(path)
+  local items = {}
+  local pipe = io.popen("find " .. quote(full(path))
+    .. " -mindepth 1 -maxdepth 1 -printf '%f\\n' 2>/dev/null")
+  if pipe then
+    for item in pipe:lines() do items[#items + 1] = item end
+    pipe:close()
+  end
+  table.sort(items)
+  return items
+end
+function fs.getSaveDirectory() return root end
+
+love = require("tests.love_stub")
+love.filesystem = fs
+
+local Loader = require("src.mods.Loader")
+local SaveData = require("src.core.SaveData")
+local SaveSerializer = require("src.core.SaveSerializer")
+local GameMethods = require("src.core.Game")
+local StateStack = require("src.core.StateStack")
+
+local function writeProbe()
+  fs.write("mods/cold_start_probe/manifest.json",
+    '{"id":"cold_start_probe","name":"cold start probe","version":"1.0.0",'
+      .. '"entry":"main.lua","api":2,"profile":"content"}')
+  fs.write("mods/cold_start_probe/main.lua", [[
+return function(mod)
+  _G.COLD_STORAGE = mod.storage
+  _G.COLD_CHECKPOINTS = mod.checkpoints
+end
+]])
+end
+
+local function runtime(save, title)
+  local stack = setmetatable({ states = {} }, { __index = StateStack })
+  local game
+  local overworld = {
+    map = { id = "PALLET_TOWN" },
+    player = { cellX = 3, cellY = 6, facing = "down", surfing = false },
+    scriptMoves = {}, pendingScripts = {}, parallelRunners = {}, parallelQueue = {},
+    runner = { isRunning = function() return false end },
+  }
+  function overworld:captureSave(target)
+    target.player.map, target.player.x, target.player.y = self.map.id,
+      self.player.cellX, self.player.cellY
+    target.player.facing, target.player.surfing = self.player.facing,
+      self.player.surfing and true or false
+  end
+  function overworld:enter(mapId, x, y, facing)
+    self.map = { id = mapId }
+    self.player = { cellX = x, cellY = y, facing = facing,
+      surfing = game.save.player.surfing and true or false }
+    self.scriptMoves, self.pendingScripts = {}, {}
+    self.parallelRunners, self.parallelQueue = {}, {}
+    self.runner = { isRunning = function() return false end }
+  end
+  game = setmetatable({
+    save = save, stack = stack, overworld = overworld,
+    data = {
+      pokemon = {}, moves = { TACKLE = { pp = 35 } }, items = { POTION = {} },
+      constants = { fallbackMove = "TACKLE" },
+      field = { boot = { startMap = "PALLET_TOWN", startX = 3, startY = 6 } },
+      maps = { PALLET_TOWN = { id = "PALLET_TOWN", width = 10, height = 9 } },
+    },
+  }, { __index = GameMethods })
+  stack.states[1] = title and { screenId = "TitleState" } or overworld
+  if title then function game:makeTitleState() return { screenId = "TitleState" } end end
+  return game
+end
+
+writeProbe()
+SaveData.resetSlotState()
+local loader = Loader.new({ fs = fs })
+
+if phase == "capture" then
+  local game = runtime(SaveData.newGame({ version = "red" }), false)
+  loader.game = game
+  assert(loader:load({}) == true)
+  assert(_G.COLD_STORAGE:write(game, "history/index", { newest = "q0001" }))
+  local checkpoint = assert(_G.COLD_CHECKPOINTS:capture(game))
+  assert(_G.COLD_STORAGE:write(game, "history/q0001", checkpoint))
+  local id = assert(game.save.meta.playthroughId)
+  assert(_G.COLD_CHECKPOINTS:ensureNormalSave(game, checkpoint))
+  local normal = assert(SaveData.load("red"))
+  assert(normal.meta.playthroughId == id)
+  fs.write("cold-start-witness.lua", SaveSerializer.encode({ playthroughId = id }))
+  print("cold-start capture persisted")
+else
+  local title = runtime(SaveData.newGame({ version = "red" }), true)
+  title.save.options = { volume = 7, bindings = {} }
+  loader.game = title
+  assert(loader:load({}) == true)
+  local selected = assert(_G.COLD_STORAGE:selected(title))
+  local witness = assert(SaveSerializer.decode(assert(fs.read("cold-start-witness.lua"))))
+  assert(selected:context().playthroughId == witness.playthroughId)
+  assert(selected:read("history/index").newest == "q0001")
+  local checkpoint = assert(selected:read("history/q0001"))
+  assert(_G.COLD_CHECKPOINTS:resume(title, checkpoint))
+  assert(title.save.meta.playthroughId == witness.playthroughId)
+  assert(title.save.options.volume == 7)
+  assert(SaveSerializer.encode(_G.COLD_CHECKPOINTS:capture(title))
+    == SaveSerializer.encode(checkpoint))
+  local normal = assert(SaveData.load("red"))
+  assert(normal.meta.playthroughId == witness.playthroughId)
+  print("cold-start resume reconstructed")
+end