CLOSES #1396, CLOSES #1398, CLOSES #1400, CLOSES #1401, CLOSES #1406, CLOSES #1407, CLOSES #1411, CLOSES #1413, CLOSES #1415, CLOSES #1416, CLOSES #1417, CLOSES #1419, CLOSES #1421, CLOSES #1422, CLOSES #1423, CLOSES #1424, CLOSES #1425, CLOSES #1427, CLOSES #1428, CLOSES #1429, CLOSES #1431, CLOSES #1432, CLOSES #1433, CLOSES #1435, CLOSES #1437, CLOSES #1440, CLOSES #1441, CLOSES #1442, CLOSES #1443, CLOSES #1444, CLOSES #1447, CLOSES #1449, CLOSES #1456, CLOSES #1461, CLOSES #1464, CLOSES #1465, CLOSES #1466, CLOSES #1468, CLOSES #1469, CLOSES #1470

src/battle/BattleState.lua

@@ -4111,8 +4111,8 @@ function BattleState:awardExp()
   end
   local function applyShare(mon, split, announce)
     local playerId = self.game.save.player and self.game.save.player.id
-    local traded = mon.otId ~= nil and playerId ~= nil
-      and mon.otId ~= playerId or mon.traded == true and mon.otId == nil
+    local traded = mon.traded == true
+      or (mon.otId ~= nil and playerId ~= nil and mon.otId ~= playerId)
     local levels, gained = Experience.apply(self.data, mon, self.enemy.def,
                                             self.enemy.mon.level, self.kind == "trainer",
                                             split, traded)

src/battle/gen2/Battle.lua

@@ -1868,7 +1868,11 @@ function Battle:useMove(attacker, defender, moveId)
   if status and (def.power or 0) == 0 then
     -- A refused primary status is a failed move (effect_commands.asm:3748,
     -- :6656); a refused secondary already animated and stays unmarked (:3752).
-    if Battle.AI_FAIL_STATUSES[status]
+    if self:statusRefusedByType(defender, def.type, status) then
+      self:markMissed()
+      self:emit({ kind = "message",
+        text = "It doesn't affect " .. self:monName(defender) .. "..." })
+    elseif Battle.AI_FAIL_STATUSES[status]
         and self:aiRandomFail(attacker, defender) then
       self:markMissed()
       self:emit({ kind = "message", text = "But it failed!" })
@@ -1880,7 +1884,8 @@ function Battle:useMove(attacker, defender, moveId)
       and record.status or nil
     -- engine/battle/effect_commands.asm:6325
     if secondary and (defender.hp or 0) > 0
-        and not self:safeguarded(defender) then
+        and not self:safeguarded(defender)
+        and not self:statusRefusedByType(defender, def.type, secondary) then
       local chance = def.effectChance or 0
       if chance > 0 and rand(self.random, 100) < chance then
         self:applyStatus(defender, secondary, attacker)
@@ -2941,6 +2946,27 @@ end
 
 -- `source` is the battler that inflicted it, carried only so
 -- battle.status_inflicted can name it the way Gen 1's does.
+-- BattleCommand_Paralyze and BattleCommand_Poison refuse on a zero matchup,
+-- and the poison pair also refuses a POISON-type target: effect_commands.asm
+-- :5788 (paralyze), :3671 (poison), :3646 / :4019 (the secondary arms).
+-- Sleep, confusion and stat changes are deliberately not gated.
+function Battle:statusRefusedByType(defender, moveType, status)
+  if not (status == "paralyze" or status == "poison" or status == "toxic") then
+    return false
+  end
+  local types = (self:speciesDef(defender) or {}).types or defender.types or {}
+  if moveType then
+    local matchups = self.data.type_chart and self.data.type_chart.matchups
+    if Damage.typeMultiplier(moveType, types, matchups) == 0 then return true end
+  end
+  if status == "poison" or status == "toxic" then
+    for _, t in ipairs(types) do
+      if t == "POISON" then return true end
+    end
+  end
+  return false
+end
+
 function Battle:applyStatus(mon, status, source)
   if (mon.hp or 0) <= 0 then return false end
   -- Confusion is SUBSTATUS_CONFUSED on the cart, not a status byte: it lives
@@ -3202,6 +3228,7 @@ end
 -- player's own.
 function Battle:isOutsider(mon)
   local playerId = self.save and self.save.player and self.save.player.id
+  if mon.traded == true then return true end
   if mon.otId == nil or playerId == nil then return false end
   return mon.otId ~= playerId
 end

src/battle/gen2/Mon.lua

@@ -388,7 +388,8 @@ function Mon.stampOT(save, mon)
   mon.ot = mon.ot or player.name
   -- NpcTrade.lua:150: `ot` is what Breeding reads, `otName` what the summary prints.
   mon.otName = mon.otName or mon.ot
-  mon.otId = mon.otId or player.id
+  -- engine/battle/experience.asm:69: a traded mon keeps its own OT id
+  if not mon.traded then mon.otId = mon.otId or player.id end
   return mon
 end
 

src/core/Game.lua

@@ -1233,6 +1233,7 @@ function Game:restoreSave(loaded, recovered, opts)
   self:applyOptions(loaded.options)
   -- saves from before OT/ID stamping: backfill with the player's (after
   -- the scrub, so every mon the stamp loop sees is known)
+  SaveData.repairTradedOtIds(loaded)
   local stamp = require("src.battle.BattleState").stampOT
   for _, mon in ipairs(loaded.party or {}) do stamp(loaded, mon) end
   for _, box in ipairs(loaded.boxes or {}) do

src/core/SaveData.lua

@@ -1923,6 +1923,26 @@ function SaveData.applyPostGameHome(save, boot)
   return heal
 end
 
+-- 0.1.82-0.1.9x loads stamped the player's own id onto traded mons and saved
+-- it, which reads back as home-caught.  A caught mon can never carry
+-- traded=true, so clearing that pair is safe on every load.  #1461
+function SaveData.repairTradedOtIds(save)
+  local playerId = save and save.player and save.player.id
+  if playerId == nil then return 0 end
+  local fixed = 0
+  local function scrub(mon)
+    if mon and mon.traded == true and mon.otId == playerId then
+      mon.otId = nil
+      fixed = fixed + 1
+    end
+  end
+  for _, mon in ipairs(save.party or {}) do scrub(mon) end
+  for _, box in ipairs(save.boxes or {}) do
+    for _, mon in ipairs(box) do scrub(mon) end
+  end
+  return fixed
+end
+
 -- Softlocked 0.1.11 saves: still standing in HALL_OF_FAME after credits,
 -- with lastOutdoor on Indigo.  One-shot rescue on CONTINUE.
 function SaveData.needsPostGameRescue(save)