Segmentation Fault on macOS when closing QGraphicsView after drag gesture

Issue

On macOS, when using QGraphicsView, performing a drag gesture inside the view and then closing the application causes a segmentation fault.

Steps to reproduce

1. Run the following minimal example:
   from PyQt6.QtWidgets import QApplication, QGraphicsView
   app = QApplication([])
   v = QGraphicsView()
   v.show()
   app.exec()
    
2. Drag inside the QGraphicsView window.
3. Close the window.

Expected behavior

The application should exit cleanly without crashing.

Actual behavior

A segmentation fault occurs, and the following crash log is generated:
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libqcocoa.dylib 0x104351a94 0x1042f8000 + 367252
1 AppKit 0x1973cab5c -[NSTouch dealloc] + 48
2 CoreFoundation 0x1935987b0 {}RELEASE_OBJECTS_IN_THE_SET{} + 148
3 CoreFoundation 0x1935986cc -[__NSSetM dealloc] + 148
4 AppKit 0x1972842a4 -[NSEvent dealloc] + 68
5 libqcocoa.dylib 0x10430d3c4 0x1042f8000 + 86980
...

Workaround

A temporary workaround that prevents the crash is to use app.aboutToQuit.connect(safe_exit), as shown below:
from PyQt6.QtWidgets import QApplication, QGraphicsView

app = QApplication([])
v = QGraphicsView()
v.show()

def safe_exit():
    for _ in range(5):
        app.processEvents()

app.aboutToQuit.connect(safe_exit)
app.exec()
 
This suggests that the issue might be related to improper cleanup of macOS touch events when QGraphicsView is destroyed.

Environment

• Qt Version: 6.8.0
• macOS Version: 15.3
• Python Version: 3.12.8
• PyQt Version: 6.8.0
• Installation Method: pip install PyQt6

Additional Notes

This issue does not occur on Windows or Linux, only on macOS.
It is likely related to libqcocoa.dylib and how macOS touch events are handled.