input sticky bug

main.lua

@@ -173,6 +173,28 @@ function love.gamepadaxis(joystick, axis, value)
   Game:gamepadaxis(joystick, axis, value)
 end
 
+function love.joystickremoved(joystick)
+  if editorMode then return end
+  if Importer then return end
+  Game:joystickremoved(joystick)
+end
+
+-- f is true on focus gained, false on focus lost (e.g. alt-tab). A held
+-- direction's key-up can be delivered to the OS instead of the game while
+-- unfocused, so reset input on either transition rather than trust it.
+function love.focus(f)
+  if editorMode then return end
+  if Importer then return end
+  Game:focus(f)
+end
+
+-- v is true when the window becomes visible again, false on minimize.
+function love.visible(v)
+  if editorMode then return end
+  if Importer then return end
+  Game:visible(v)
+end
+
 function love.touchpressed(id, x, y, dx, dy, pressure)
   if editorMode then return end
   if Importer then return Importer:mousepressed(x, y, 1) end

src/core/Game.lua

@@ -349,6 +349,28 @@ function Game:gamepadaxis(joystick, axis, value)
   Input:gamepadaxis(joystick, axis, value)
 end
 
+-- Window lost focus or got minimized: any release event due while it was
+-- unfocused/hidden can be swallowed by the OS instead of delivered here,
+-- which would otherwise leave a held direction stuck on.
+function Game:focus(f)
+  if f then return end
+  Input:reset()
+  TouchInput:reset()
+end
+
+function Game:visible(v)
+  if v then return end
+  Input:reset()
+  TouchInput:reset()
+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()
+end
+
 function Game:touchpressed(id, x, y)
   TouchInput:touchpressed(id, x, y)
 end

src/core/Input.lua

@@ -32,6 +32,15 @@ local STICK_ON = 0.5
 local STICK_OFF = 0.3
 
 function Input:init()
+  self:reset()
+end
+
+-- Purely event-driven state (press sets true, release sets false) has no
+-- fallback if a release event never arrives -- focus loss, a minimized
+-- window, or a disconnected gamepad can all swallow the key-up/button-up
+-- that would have cleared a held direction. Called from Game on those
+-- transitions so a stuck flag can't outlive them.
+function Input:reset()
   self.state = {}
   self.pressQueue = {}
   self.pressed = {}

src/core/TouchInput.lua

@@ -75,6 +75,21 @@ function TouchInput:init()
   self.selectFired = false     -- one SELECT per two-finger gesture cluster
 end
 
+-- LÖVE has no touchcancelled event, so a touch interrupted by the OS (app
+-- backgrounded mid-touch, a system gesture stealing the finger) never fires
+-- touchreleased and would otherwise strand its direction held forever.
+-- Called from Game alongside Input:reset() on focus/visibility loss.
+function TouchInput:reset()
+  for _, touch in pairs(self.touches) do
+    releaseDir(self, touch)
+  end
+  self.touches = {}
+  self.pendingA = nil
+  self.armed = {}
+  self.autoRelease = {}
+  self.selectFired = false
+end
+
 local function pulse(self, key)
   Input:keypressed(key)
   self.armed[#self.armed + 1] = key