Fix #11438: Crash when decreasing map size

[Gymnasiast]

The issue was caused by the code trying to remove a park entrance element that was not one that it knew about. It therefore refused to remove the tile element, caused code further upstream to get into an infinite loop.

Since clear_element_at is only called from functions that either clear the map completely or clear all the out of range elements, I figured that forcibly removing them was not too much of a problem.

[IntelOrca]

If calling tile_element_remove works, why do we need to execute game actions at all?

[Gymnasiast]

Because they also do stuff like cleaning up banner entries and removing park entrances from the global list. tile_element_remove() is used as a last resort.

[ZehMatt]

How does it not know that the entrance exists? Seems like an issue that is not handled correctly elsewhere.

[Gymnasiast]

There are countless reasons why the tile elements can be incorrect. One of them is simply copying stuff using the Tile Inspector.

[ZehMatt]

I'm not a big fan about having a forced removal for all the other elements, given the entrance is not registered is the fault of the tile inspector, the removal logic is correct.

[Gymnasiast]

As I said, there are more reasons why it might be incorrect. Corruption of tile elements is very common and I'm frankly a bit surprised that you seem unaware of this.

[ZehMatt]

I'm aware that things can get corrupted but that is exactly my point, fighting the code that corrupts the state rather than hiding it. I understand to why the park entrance can get into this situation but the cause is apparently known so we should fix it there. As for the other corruptions we need to identify the cause. In my experience attempts like this usually shift the issue elsewhere, that is why I think the fix is fine for the entrance only but not for the rest.

[IntelOrca]

@ZehMatt it needs to handle all edge cases regardless of how they may have been introduced

[ZehMatt]

I think it would be better to adjust the game actions in that regard, one thing that comes to my mind is have a flag that skips most of the things in query, the code needs to check of course for this specific flag. Its somewhat close to the clearance check. This is a cleaner solution and the plugins could also benefit to apply the specific flag to skip certain checks.