Robot Manager targetting an absorbed robot crashes the game on Windows with certain inputs about principia

[rollerozxa]

Can indeed reproduce.

Strangely only crashes on Windows, works fine on Linux.

[griffi-gh]

i think this is another use after free...?

[rollerozxa]

Yes, obviously.

[griffi-gh]

seems like the Robot Manager never receives ENTITY_EVENT_REMOVE, even though it's subscribed to it
literally have no idea why this doesn't work, since Lua Script relies on the same event and it does work there... (even if it's actually not handled properly)

[griffi-gh]

seems like subscriptions get reset??? between initialization and actual absorb.
calling subscribe every frame (hack) fixes the issue....??

[griffi-gh]

principia/src/src/entity.hh

Lines 839 to 845 in 87b00fb

	/* Setup is called after init if the entity has no
	* state to load from */
	virtual void setup()
	{
	this->listeners.clear();
	this->subscriptions.clear();
	};

... interesting...
seems like this is a side effect of the default setup implementation, which clears all listeners and subscriptions
(The robot manager subscribes to the ENTITY_EVENT_REMOVE event in the init "stage", which gets called before setup)

Commenting out the following lines in the setup implementation "fixes" the issue:

// this->listeners.clear();
// this->subscriptions.clear();

But I'm pretty sure this has some unintended side effects...

By the way, saving and reloading the state before the robot is absorbed causes the game to not crash, since setup is not called if the level is reloaded from a state buffer:

principia/src/src/entity.cc

Lines 560 to 578 in 87b00fb

	* ENTITY STATE HANDLING
	*
	* When a level is saved, write_state is called from world. The entity can fill however
	* much data in the buffer as it wishes.
	*
	* When the level is loaded again, the following occurs:
	* 1. Entity allocates
	* 2. on_load(bool created, bool has_state)
	* 3. read_state()
	* 4. add_to_world()
	* 5. init()
	* 6. restore()
	*
	* When a level is loaded without a state buffer, the follow occurs:
	* 1. Entity allocates
	* 2. on_load(bool created, bool has_state)
	* 3. add_to_world()
	* 4. init()
	* 5. setup()