From ea7fbf7947ac87f134569efc1af2661ba3455ff1 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Wed, 3 Aug 2022 19:39:37 -0700
Subject: [PATCH] Update in-flight SDL_CONTROLLERDEVICEADDED messages when a
 device is removed

This fixes the application trying to open the wrong device index when a device is removed and another has just been added
---
 src/joystick/SDL_joystick.c | 39 +++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/src/joystick/SDL_joystick.c b/src/joystick/SDL_joystick.c
index 931aa9e46..78ac09609 100644
--- a/src/joystick/SDL_joystick.c
+++ b/src/joystick/SDL_joystick.c
@@ -1331,13 +1331,13 @@ void SDL_PrivateJoystickAdded(SDL_JoystickID device_instance)
  * to have the right value for which, because the number of controllers in
  * the system is now one less.
  */
-static void UpdateEventsForDeviceRemoval(int device_index)
+static void UpdateEventsForDeviceRemoval(int device_index, Uint32 type)
 {
     int i, num_events;
     SDL_Event *events;
     SDL_bool isstack;
 
-    num_events = SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, SDL_JOYDEVICEADDED, SDL_JOYDEVICEADDED);
+    num_events = SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, type, type);
     if (num_events <= 0) {
         return;
     }
@@ -1347,20 +1347,38 @@ static void UpdateEventsForDeviceRemoval(int device_index)
         return;
     }
 
-    num_events = SDL_PeepEvents(events, num_events, SDL_GETEVENT, SDL_JOYDEVICEADDED, SDL_JOYDEVICEADDED);
+    num_events = SDL_PeepEvents(events, num_events, SDL_GETEVENT, type, type);
     for (i = 0; i < num_events; ++i) {
-        if (events[i].cdevice.which < device_index) {
-            /* No change for index values lower than the removed device */
+        Sint32 which = -1;
+        switch (type) {
+        case SDL_JOYDEVICEADDED:
+            which = events[i].jdevice.which;
+            break;
+        case SDL_CONTROLLERDEVICEADDED:
+            which = events[i].cdevice.which;
+            break;
+        default:
+            break;
         }
-        else if (events[i].cdevice.which == device_index) {
+        if (which < device_index) {
+            /* No change for index values lower than the removed device */
+        } else if (which == device_index) {
             /* Drop this event entirely */
             SDL_memmove(&events[i], &events[i + 1], sizeof(*events) * (num_events - (i + 1)));
             --num_events;
             --i;
-        }
-        else {
+        } else {
             /* Fix up the device index if greater than the removed device */
-            --events[i].cdevice.which;
+            switch (type) {
+            case SDL_JOYDEVICEADDED:
+                --events[i].jdevice.which;
+                break;
+            case SDL_CONTROLLERDEVICEADDED:
+                --events[i].cdevice.which;
+                break;
+            default:
+                break;
+            }
         }
     }
     SDL_PeepEvents(events, num_events, SDL_ADDEVENT, 0, 0);
@@ -1427,7 +1445,8 @@ void SDL_PrivateJoystickRemoved(SDL_JoystickID device_instance)
         SDL_PushEvent(&event);
     }
 
-    UpdateEventsForDeviceRemoval(device_index);
+    UpdateEventsForDeviceRemoval(device_index, SDL_JOYDEVICEADDED);
+    UpdateEventsForDeviceRemoval(device_index, SDL_CONTROLLERDEVICEADDED);
 #endif /* !SDL_EVENTS_DISABLED */
 
     SDL_LockJoysticks();