so many bugs i cannot even breathe

tests/parity_warp_after_warp_step.lua

@@ -2,8 +2,10 @@
 -- under the player's feet (#265).  home/overworld.asm:391 CheckWarpsNoCollision
 -- runs on EVERY completed step with no first-step-after-a-warp counter, so the
 -- arrival disable is POSITIONAL (the cell you came in on is inert until you
--- leave it), which is what warpEntryCell models.  #230's stand-still bonk guard,
--- still backed by justWarped, is asserted here too.
+-- leave it), which is what warpEntryCell models.  The two STAND-STILL triggers
+-- answer to BIT_STANDING_ON_WARP instead, which the departing tile decides and
+-- the warp carries over: cleared by a staircase (#230), kept by a door tile so
+-- an exit mat works on the tile you land on (#378).  Both are asserted here.
 package.path = "./?.lua;./?/init.lua;" .. package.path
 if not _G.love then _G.love = require("tests.love_stub") end
 
@@ -48,15 +50,18 @@ Game.overworld = OW
 -- these two fields once setMap has placed the player (OverworldController.lua,
 -- inside the Transition callback).  takeWarp is stubbed per instance so the
 -- assertion is which warp the engine decided to take, with no Transition to pump.
-local function arriveOn(mapId, x, y, facing)
+local function arriveOn(mapId, x, y, facing, standingOnWarp)
   Input:reset()
   while Game.stack:top() do Game.stack:pop() end
   Game.stack:push(OW, mapId, x, y, facing or "down")
   local ow = Game.stack:top()
   ow.player.moving = false
   ow.player.turnTimer = 0
-  ow.justWarped = true
   ow.warpEntryCell = { x = x, y = y }
+  -- BIT_STANDING_ON_WARP is whatever the tile we LEFT made it: a door tile
+  -- leaves it set, a stair/ladder tile clears it, and the map change does not
+  -- touch wMovementFlags.
+  ow.standingOnWarp = standingOnWarp and true or false
   ow.taken = nil
   ow.takeWarp = function(self, def) self.taken = def end
   return ow
@@ -77,16 +82,16 @@ end
 -- onto the adjacent ladder at (25,4).
 do
   local ow = arriveOn("SEAFOAM_ISLANDS_B3F", 25, 3, "down")
-  check(ow:onWarpArrivalCell(), "the cell just arrived on is inert")
+  check(ow.warpEntryCell ~= nil, "the cell just arrived on is inert")
   stepTo(ow, 25, 4, "down")
   check(ow.taken ~= nil, "the step onto (25,4) fires a warp")
   eq(ow.taken and ow.taken.destMap, "SEAFOAM_ISLANDS_B4F",
      "and it is the ladder down to B4F")
-  check(ow.justWarped == false, "the arrival record is cleared by that step")
+  check(ow.warpEntryCell == nil, "the arrival record is cleared by that step")
 end
 
 -- The arrival cell stays inert while you stand on it, even if a scripted nudge
--- re-runs the step handler there.  That is warpEntryCell's job, not justWarped's.
+-- re-runs the step handler there.  That is warpEntryCell's job.
 do
   local ow = arriveOn("SEAFOAM_ISLANDS_B3F", 25, 3, "down")
   stepTo(ow, 25, 3, "down")
@@ -106,12 +111,14 @@ do
   eq(ow.taken and ow.taken.destMap, "SEAFOAM_ISLANDS_B2F", "back up to B2F")
 end
 
--- #230 must not come back: justWarped still guards the two STAND-STILL warp
--- triggers, where no step ever completes.  Red's house 2F staircase is on the
--- map's east edge, so pushing into that edge has to bonk, not bounce floors.
+-- #230 must not come back: the staircase tile ($1A/$1C, a warp tile that is
+-- not a door tile) clears BIT_STANDING_ON_WARP on the step that takes it, so
+-- the two STAND-STILL triggers stay shut on arrival.  Red's house 2F staircase
+-- is on the map's east edge, so pushing into that edge has to bonk, not bounce.
 do
-  local ow = arriveOn("REDS_HOUSE_2F", 7, 1, "down")
-  check(ow:onWarpArrivalCell(), "the staircase arrival cell reports inert")
+  local ow = arriveOn("REDS_HOUSE_2F", 7, 1, "down", false)
+  check(ow:canCollisionWarp() == false,
+        "the staircase arrival leaves BIT_STANDING_ON_WARP clear")
   check(ow:checkEdgeExit("right") == false,
         "pushing east off the map edge from it does not warp (#230)")
   Input.state.right = true
@@ -138,4 +145,21 @@ do
   Input:reset()
 end
 
+-- #378: the exit mat you warped IN on is NOT inert for the collision paths.
+-- REDS_HOUSE_1F's mat (2,7) is tile $14 -- neither a door tile nor a warp tile,
+-- so nothing clears the flag that Pallet Town's door tile ($1B, a door tile)
+-- set on the way in, and the first press of DOWN walks straight back outside.
+do
+  local reds1 = MapLoader.load(Data, "REDS_HOUSE_1F")
+  eq(reds1:cellTile(2, 7), 0x14, "REDS_HOUSE_1F (2,7) is the exit mat tile")
+  check(not reds1:isWarpTileCell(2, 7), "the mat is not a warp-activating tile")
+  eq(reds1.def.height * 2, 8,
+     "REDS_HOUSE_1F is 8 cells tall, so y=7 is the south edge")
+
+  local ow = arriveOn("REDS_HOUSE_1F", 2, 7, "down", true)
+  check(ow:checkEdgeExit("down") == true,
+        "pressing DOWN on the mat just arrived on exits the house (#378)")
+  eq(ow.taken and ow.taken.destMap, "LAST_MAP", "back out the way we came")
+end
+
 S.finish()