Fix a crash releasing your own caught Pikachu in Yellow

BoxMenu.lua's release() pushes both its "Once released...OK?" prompt
and its Yellow-only "Pikachu looks unhappy" message through
TextBox.new(game, (t._X or Strings(...)):gsub(...)) -- gsub returns
two values (the text and a substitution count), and since the gsub
call is the last argument in the TextBox.new(...) call with nothing
after it, Lua expands both into the call: the count lands in
TextBox.new's third parameter, onDone. TextBox.lua later calls
onDone() once the box is dismissed; a number is not callable, so
every release of your own caught Pikachu in Yellow crashed --
regardless of its nickname (unlike the separate %-escape gsub bug,
this one needs no special save content, ordinary play reaches it
every time).

Fixed by wrapping the gsub call in an extra pair of parens, which
truncates it to its first return value only -- the same fix already
applied to the neighboring _OnceReleasedText/_MonWasReleasedText
lines on the (separate, unmerged) fix/route-more-messages-through-romtext
branch, where this exact bug shape was first noticed while adding a
third callsite with the same pattern.

tests/engine/pikachu_unhappy_release_crash.lua: registers a fake
Data.pokemon.PIKACHU cloned from the fixture species (ROM-free) so
the species == "PIKACHU" check can be exercised, drives the real
interactive release flow in Yellow on a mon owned by the player, and
confirms the crash. Verified failing pre-fix (exact same
"attempt to call field 'onDone' (a number value)" error) and passing
post-fix.

src/ui/BoxMenu.lua

@@ -180,8 +180,8 @@ local function release(game)
          and mon.ot == game.save.player.name then
         require("src.core.Sound").playCry(game.data, mon.species)
         game.stack:push(TextBox.new(game,
-          (t._PikachuUnhappyText or Strings("%s looks\nunhappy about it!", name))
-            :gsub("{RAM:wNameBuffer}", name)))
+          ((t._PikachuUnhappyText or Strings("%s looks\nunhappy about it!", name))
+            :gsub("{RAM:wNameBuffer}", name))))
         return
       end
       game.stack:push(TextBox.new(game,

tests/engine/pikachu_unhappy_release_crash.lua

@@ -0,0 +1,106 @@
+-- BoxMenu's Yellow-only "Pikachu looks unhappy" release path
+-- (release()'s isYellow()/species=="PIKACHU"/otId/ot branch) pushes its
+-- TextBox with `TextBox.new(game, (...):gsub(...))` -- the gsub call is
+-- the last argument, unparenthesized, so Lua expands its second return
+-- value (the substitution count) into TextBox.new's third parameter,
+-- onDone.  TextBox.lua later calls onDone() unconditionally once the box
+-- is dismissed, and a number is not callable: every release of your own
+-- caught Pikachu in Yellow crashed, regardless of its nickname (unlike
+-- the separate %-escape gsub bug, this needs no special save content --
+-- ordinary play reaches it every time).  ROM-free: registers a fake
+-- Data.pokemon.PIKACHU cloned from the fixture species so the species ==
+-- "PIKACHU" check can be exercised without a real ROM import.
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+local T = require("tests.modkit")
+local Data = T.fixtures.fresh()
+local ids = T.fixtures.ids
+require("src.render.Font").load(Data)
+
+-- clone a real fixture species under the literal id release() checks for
+Data.pokemon.PIKACHU = Data.pokemon[ids.species[1]]
+
+local Pokemon = require("src.pokemon.Pokemon")
+local Boxes = require("src.pokemon.Boxes")
+local TextBox = require("src.render.TextBox")
+local BoxMenu = require("src.ui.BoxMenu")
+local ListMenu = require("src.ui.ListMenu")
+local ChoiceBox = require("src.ui.ChoiceBox")
+local SaveData = require("src.core.SaveData")
+local GameVersion = require("src.core.GameVersion")
+local Sound = require("src.core.Sound")
+
+local realCry, realPlay = Sound.playCry, Sound.play
+Sound.playCry = function() end
+Sound.play = function() end
+
+local stack = { states = {} }
+function stack:push(s) self.states[#self.states + 1] = s end
+function stack:pop()
+  local t = self.states[#self.states]
+  self.states[#self.states] = nil
+  return t
+end
+function stack:top() return self.states[#self.states] end
+function stack:update(dt)
+  local t = self:top()
+  if t and t.update then t:update(dt) end
+end
+
+local pressed = {}
+local function press(btn)
+  pressed = { [btn] = true }
+  stack:update(1 / 60)
+  pressed = {}
+end
+
+local function topMt() return getmetatable(stack:top()) end
+local function mash(btn, cond, n)
+  for _ = 1, (n or 400) do
+    if cond() then return true end
+    press(btn)
+  end
+  return false
+end
+
+GameVersion.set("yellow")
+
+local save = SaveData.newGame()
+local game = {
+  data = Data,
+  save = save,
+  stack = stack,
+  input = {
+    wasPressed = function(_, key) return pressed[key] or false end,
+    isDown = function() return false end,
+  },
+}
+game.save.options = game.save.options or {}
+game.save.options.textSpeed = 1
+
+local box = Boxes.active(save)
+local mon = Pokemon.new(Data, "PIKACHU", 5)
+mon.otId = save.player.id
+mon.ot = save.player.name
+box[1] = mon
+
+stack:push(BoxMenu.new(game))
+press("down"); press("down"); press("a") -- open RELEASE list
+T.check(topMt() == ListMenu, "RELEASE opens the box list")
+
+-- release() calls Sound.playCry (stubbed) then pushes the "unhappy"
+-- TextBox before any confirmation prompt -- pre-fix this line itself
+-- raises "attempt to call field 'onDone' (a number value)" the moment
+-- TextBox.new stores the leaked count and something dismisses the box.
+local ok, err = pcall(function()
+  press("a") -- choose the Pikachu; release() runs synchronously here
+  T.check(topMt() == TextBox, "the unhappy-Pikachu TextBox opens directly, no confirm prompt")
+  -- dismiss it: this is what calls onDone, which is where the pre-fix
+  -- leaked count used to crash
+  mash("a", function() return topMt() ~= TextBox end)
+end)
+T.check(ok, "releasing your own caught Pikachu in Yellow does not crash: " .. tostring(err))
+
+GameVersion.set("red")
+Sound.playCry, Sound.play = realCry, realPlay
+T.finish("pikachu_unhappy_release_crash")