Keep the bag open after using a Rare Candy (#796)

src/ui/BagMenu.lua

@@ -255,6 +255,15 @@ local function useOn(game, battle, id, target, list, moveIndex, picker)
 
   if result == "consumed" then
     consume(game, id)
+    -- refresh counts in the list
+    for i, it in ipairs(list.items) do
+      if it.value == id then
+        local left = game.save.inventory[id]
+        if left then it.right = "x" .. left else table.remove(list.items, i) end
+        break
+      end
+    end
+    list.index = math.min(list.index, math.max(1, #list.items))
     if extra and extra.evolveTo then
       list:close()
       local Evolution = require("src.pokemon.Evolution")
@@ -265,7 +274,11 @@ local function useOn(game, battle, id, target, list, moveIndex, picker)
     -- moves and a level evolution follow (item_effects.asm .useRareCandy
     -- runs PrintStatsBox, LearnMoveFromLevelUp and TryEvolvingMon)
     if extra and extra.leveledTo and target then
-      list:close()
+      -- ...but the bag stays open underneath it all: RARE_CANDY is in
+      -- pokered's UsableItems_PartyMenu (data/items/use_party.asm), and
+      -- .useItem_partyMenu jumps back to StartMenu_Item once UseItem
+      -- returns, cursor still on the candy (start_sub_menus.asm) -- so
+      -- mashing A burns through a stack of them (#796)
       showMessages(game, payload, function()
         local StatBox = require("src.battle.BattleState").StatBox
         game.stack:push(StatBox.new(game, target, function()
@@ -304,15 +317,6 @@ local function useOn(game, battle, id, target, list, moveIndex, picker)
       end)
       return
     end
-    -- refresh counts in the list
-    for i, it in ipairs(list.items) do
-      if it.value == id then
-        local left = game.save.inventory[id]
-        if left then it.right = "x" .. left else table.remove(list.items, i) end
-        break
-      end
-    end
-    list.index = math.min(list.index, math.max(1, #list.items))
     -- HP medicine: fill the bar in the still-open picker first, then print
     -- and close, the order item_effects.asm .doneHealing runs in
     -- (SFX_HEAL_HP -> UpdateHPBar2 -> RedrawPartyMenu prints the message).

tests/parity_rare_candy_menu.lua

@@ -0,0 +1,179 @@
+-- Parity test: using a RARE CANDY from the bag returns to the bag (#796).
+--
+-- pokered files RARE_CANDY under UsableItems_PartyMenu (data/items/
+-- use_party.asm), so after UseItem runs, start_sub_menus.asm's
+-- .useItem_partyMenu jumps back to StartMenu_Item with wBagSavedMenuItem
+-- still pointing at the candy -- the level text, PrintStatsBox, the
+-- level-up moves and any level evolution all happen first, then the item
+-- list is back with the cursor on the candy, which is what lets the
+-- original button-mash through a stack of them.  The port closed the bag
+-- list before the level-up sequence and never reopened it, so every candy
+-- cost a full START -> ITEM trip.
+--
+-- Self-contained; run via `luajit tests/parity_rare_candy_menu.lua`.
+package.path = "./?.lua;./?/init.lua;" .. package.path
+if not _G.love then _G.love = require("tests.love_stub") end
+local S = require("tests.harness").suite("parity rare candy menu")
+local check, eq = S.check, S.eq
+
+local Data = require("src.core.Data")
+Data:load()
+
+local Pokemon = require("src.pokemon.Pokemon")
+local Bag = require("src.inventory.Bag")
+
+-- Real TextBoxes want a Font atlas; the flow under test only cares which
+-- states land on the stack and what each onDone does.  BagMenu binds
+-- TextBox at require time, so it is reloaded against the stub here and
+-- dropped again at the bottom.
+local realTextBox = package.loaded["src.render.TextBox"]
+local realBag = package.loaded["src.ui.BagMenu"]
+local realParty = package.loaded["src.ui.PartyMenu"]
+package.loaded["src.render.TextBox"] = {
+  new = function(_, text, done) return { textBox = true, text = text, done = done } end,
+}
+package.loaded["src.ui.BagMenu"] = nil
+package.loaded["src.ui.PartyMenu"] = nil
+local BagMenu = require("src.ui.BagMenu")
+local PartyMenu = require("src.ui.PartyMenu")
+require("src.ui.Screens").invalidate()
+
+-- A stack that behaves like StateStack for the two things this flow reads:
+-- top() identity (ListMenu:close) and push/pop ordering.
+local function newStack()
+  local stack = { states = {} }
+  function stack:push(s) self.states[#self.states + 1] = s end
+  function stack:pop() return table.remove(self.states) end
+  function stack:top() return self.states[#self.states] end
+  return stack
+end
+
+-- One button per call: PartyMenu:update reads game.input once per fixed step.
+local function newInput()
+  local input = { pressed = nil }
+  function input:wasPressed(b) return self.pressed == b end
+  return input
+end
+
+-- CHARIZARD learns nothing at level 51 and has no evolution left, so a
+-- candy on it ends after the stat window -- no MoveLearnMenu, no
+-- EvolutionState clouding which state the stack returns to.
+local function freshGame(candies)
+  local lead = Pokemon.new(Data, "CHARIZARD", 50)
+  local game = {
+    data = Data,
+    stack = newStack(),
+    input = newInput(),
+    save = {
+      party = { lead },
+      player = { name = "RED" },
+      inventory = {},
+      options = { battleStyle = "set", battleAnim = "on" },
+      pokedex = { seen = {}, owned = {} },
+      flags = {},
+      money = 0,
+    },
+  }
+  Bag.add(game.save, "RARE_CANDY", candies or 3)
+  return game, lead
+end
+
+local function isPicker(s) return getmetatable(s) == PartyMenu end
+local function isBox(s) return type(s) == "table" and s.textBox == true end
+
+-- TextBox pops itself BEFORE firing onDone.
+local function dismiss(stack, box)
+  if stack:top() == box then stack:pop() end
+  if box.done then box.done() end
+end
+
+local function rowFor(list, id)
+  for i, r in ipairs(list.items) do
+    if r.value == id then return i end
+  end
+  return nil
+end
+
+-- From an already-open bag list: choose the candy, take USE off the
+-- submenu, press A on the party picker.  Returns the level-up text box.
+local function useCandy(game, list)
+  local row = rowFor(list, "RARE_CANDY")
+  if not row then return nil, "no RARE CANDY row in the bag" end
+  list.index = row
+  list.onChoose(list.items[row], list)
+  -- out of battle the bag offers USE / TOSS first (start_sub_menus.asm)
+  local sub = game.stack:top()
+  if sub and sub.items and sub.items[1] and sub.items[1].onSelect then
+    game.stack:pop()
+    sub.items[1].onSelect()
+  end
+  local picker = game.stack:top()
+  if not isPicker(picker) then return nil, "party picker never opened" end
+  game.input.pressed = "a"
+  picker:update(1 / 60)
+  game.input.pressed = nil
+  return game.stack:top()
+end
+
+-- Walk the rest of the level-up sequence: dismiss the level text, then A
+-- through the stat window (PrintStatsBox).
+local function finishLevelUp(game, box)
+  dismiss(game.stack, box)
+  local top = game.stack:top()
+  if isBox(top) then return end -- a "learned MOVE" line, dismissed by caller
+  if top and top.update then
+    game.input.pressed = "a"
+    top:update(1 / 60)
+    game.input.pressed = nil
+  end
+end
+
+-- ---- the report: one candy closed the whole menu -------------------------
+do
+  local game, lead = freshGame(3)
+  local list = BagMenu.new(game, {})
+  game.stack:push(list)
+  local row = rowFor(list, "RARE_CANDY")
+  check(row ~= nil, "the candy is in the bag")
+
+  local box = useCandy(game, list)
+  check(isBox(box), "the level text opened")
+  eq(lead.level, 51, "the candy leveled the mon")
+  eq(game.save.inventory.RARE_CANDY, 2, "the candy was consumed")
+  check(game.stack.states[1] == list,
+        "the bag list is STILL on the stack under the level text (#796)")
+
+  finishLevelUp(game, box)
+  eq(game.stack:top(), list,
+     "after the stat window the bag is back on top (StartMenu_Item)")
+  eq(list.index, row, "the cursor is still on the RARE CANDY row")
+  eq(list.items[row] and list.items[row].right, "x2",
+     "the count refreshed in place")
+
+  -- the point of the original's behavior: a second candy needs no menu trip
+  local box2 = useCandy(game, list)
+  check(isBox(box2), "a second candy fires from the still-open bag")
+  eq(lead.level, 52, "and it levels the mon again")
+  finishLevelUp(game, box2)
+  eq(game.stack:top(), list, "still on the bag after the second candy")
+  eq(game.save.inventory.RARE_CANDY, 1, "two candies spent")
+end
+
+-- ---- the last candy: the row empties but the bag still stays up ----------
+do
+  local game = freshGame(1)
+  local list = BagMenu.new(game, {})
+  game.stack:push(list)
+  local box = useCandy(game, list)
+  check(isBox(box), "the last candy levels too")
+  finishLevelUp(game, box)
+  eq(game.stack:top(), list, "the bag stays open after the last candy")
+  eq(#list.items, 0, "the emptied row left the list")
+  eq(game.save.inventory.RARE_CANDY, nil, "no candies left in the inventory")
+end
+
+package.loaded["src.render.TextBox"] = realTextBox
+package.loaded["src.ui.BagMenu"] = realBag
+package.loaded["src.ui.PartyMenu"] = realParty
+require("src.ui.Screens").invalidate()
+S.finish()