64 attached or detached BulletAppStates with parallel threading causes JVM to crash

[James-Richardson]

If your game is routinely attaching and detaching BulletAppStates, once it attaches the 64th BulletAppState, the JVM crashes.

Note that the issue isn't that there are more than 64 BulletAppStates currently attached. The JVM crashes if more than 64 BulletAppStates have previously been attached, and even if the current number of attached BulletAppStates is far less than 64.

This issue can be reproduced with the following code, in which case only one BulletAppState is ever attached, but it is attached and detached more than 64 times:

    private int count;
    private int frame;
    private BulletAppState bulletAppState;
    
    @Override
    public void simpleInitApp() {}
    
    @Override
    public void simpleUpdate(float tpf) {
        if (frame % 4 == 0) {
            System.out.println(++count);
            
            bulletAppState = new BulletAppState();
            
            bulletAppState.setThreadingType(ThreadingType.PARALLEL);
            
            stateManager.attach(bulletAppState);
        } else if (frame % 4 == 2) {
            stateManager.detach(bulletAppState);
        }
        
        frame++;
    }

More information on this issue can be found in the original forum topic.

[stephengold]

Fixed in master branch.

[stephengold]

Note that the underlying issue was fixed in Bullet at bulletphysics/bullet3@ee0e3ba

That made disabling Bullet's Quickprof profiling completely unnecessary.

At some point, Bullet's mechanism for enabling/disabling profiling was changed. As a consequence, the fix for #928 actually doesn't disable Quickprof any more.