fix(input): recover cleanly on joystick reconnect

Co-authored-by: Cursor <cursoragent@cursor.com>

main.lua

@@ -393,6 +393,13 @@ function love.joystickhat(joystick, hat, direction)
   Game:joystickhat(joystick, hat, direction)
 end
 
+function love.joystickadded(joystick)
+  SwitchDiagnostics.onJoystickEvent("joystickadded", joystick)
+  if editorMode or TouchEditor then return end
+  if Importer then return end
+  Game:joystickadded(joystick)
+end
+
 function love.joystickremoved(joystick)
   SwitchDiagnostics.onJoystickEvent("joystickremoved", joystick)
   if editorMode or TouchEditor then return end
@@ -423,6 +430,11 @@ function love.visible(v)
   Game:visible(v)
 end
 
+function love.lowmemory()
+  if editorMode or TouchEditor or Importer then return end
+  if Game then Game:onResume() end
+end
+
 function love.touchpressed(id, x, y, dx, dy, pressure)
   if editorMode then return end
   if TouchEditor then

src/core/Game.lua

@@ -546,15 +546,48 @@ function Game:focus(f)
 end
 
 function Game:visible(v)
+  if v then
+    self:onResume()
+  else
     Input:reset()
     TouchControls:reset()
   end
+end
+
+function Game:onResume()
+  Input:reset()
+  TouchControls:reset()
+  -- Chip music may survive suspend as a duplicate stream; stop it and let
+  -- the active screen re-cue on the next frame (hardware audio check: T19).
+  require("src.core.ChipAudio").stopMusic()
+  local SwitchDiagnostics = require("src.debug.SwitchDiagnostics")
+  if SwitchDiagnostics.isEnabled() then
+    SwitchDiagnostics.onEvent("lifecycle", { event = "resume" })
+  end
+end
+
+function Game:recoverInput(event, joystick)
+  Input:reset()
+  TouchControls:reset()
+  local SwitchDiagnostics = require("src.debug.SwitchDiagnostics")
+  if SwitchDiagnostics.isEnabled() then
+    if joystick then
+      SwitchDiagnostics.onJoystickEvent(event, joystick)
+    else
+      SwitchDiagnostics.onEvent("lifecycle", { event = event })
+    end
+  end
+end
+
+function Game:joystickadded(joystick)
+  self:recoverInput("joystickadded", joystick)
+end
 
 -- A disconnected/dropped controller can't send the button-up for whatever
 -- it was holding, so drop all input state rather than try to guess which
 -- flags it owned.
 function Game:joystickremoved(joystick)
-  Input:reset()
+  self:recoverInput("joystickremoved", joystick)
   TouchControls:joystickremoved()
 end
 

tests/engine/input_joystick_recovery_test.lua

@@ -0,0 +1,30 @@
+-- Joystick remove / resume clears stuck input sources (SWNX-19).
+package.path = "./?.lua;./?/init.lua;" .. package.path
+if not _G.love then _G.love = require("tests.love_stub") end
+
+local T = require("tests.harness")
+local check = T.check
+
+local Input = require("src.core.Input")
+local Game = require("src.core.Game")
+
+Input:init()
+Input:gamepadaxis(nil, "leftx", -0.9)
+Input:step()
+check(Input:isDown("left"), "stick holds left before disconnect")
+
+Game:joystickremoved({})
+check(not Input:isDown("left"), "joystickremoved clears stick hold")
+
+Input:gamepadpressed(nil, "a")
+Input:step()
+check(Input:isDown("a"), "button held before reconnect reset")
+Game:joystickadded({ getName = function() return "Joy-Con" end })
+check(not Input:isDown("a"), "joystickadded clears stale button hold")
+
+Input:gamepadaxis(nil, "lefty", 0.9)
+Input:step()
+Game:onResume()
+check(not Input:isDown("down"), "resume clears stuck axis state")
+
+T.finish()