Python: Make sure GB link object isn't GC'd before GB object

CHANGES

@@ -11,6 +11,7 @@ Bugfixes:
  - Qt: Fix color picking in sprite view (fixes mgba.io/i/1307)
  - GB: Fix crash when accessing SRAM if no save loaded and cartridge has no SRAM
  - Python: Fix crash when deleting files owned by library
+ - Python: Make sure GB link object isn't GC'd before GB object
 Misc:
  - GBA Video: Improve sprite cycle counting (fixes mgba.io/i/1274)
 

src/platform/python/mgba/gb.py

@@ -27,6 +27,7 @@ class GB(Core):
         self.sprites = GBObjs(self)
         self.cpu = LR35902Core(self._core.cpu)
         self.memory = None
+        self._link = None
 
     @needs_reset
     def _init_cache(self, cache):
@@ -43,10 +44,13 @@ class GB(Core):
         self.memory = GBMemory(self._core)
 
     def attach_sio(self, link):
+        self._link = link
         lib.GBSIOSetDriver(ffi.addressof(self._native.sio), link._native)
 
     def __del__(self):
-        lib.GBSIOSetDriver(ffi.addressof(self._native.sio), ffi.NULL)
+        if self._link:
+            lib.GBSIOSetDriver(ffi.addressof(self._native.sio), ffi.NULL)
+            self._link = None
 
 
 create_callback("GBSIOPythonDriver", "init")