{{tag>zxt:extension}}

====== 00000001:0004 - FIX: Crash when element is recursively pushing itself ======

===== Information =====

  * **ID:** 00000001:0004

===== Flags =====

^ Flag ^ Set? (MUST/MAY/...) ^ Description ^
| parsing_must | MUST NOT | |
| reading_must | MUST NOT | |
| writing_must | MUST NOT | |
| playing_should | MAY | |
| playing_must | MAY | |
| editing_should | MUST NOT | |

===== Field data =====

None.

===== Description =====

The most common case of this is when you duplicate a player-pushable
element onto a player, which ends up calling the ''TouchProc'' against
the source element with a direction equal to the player's movement
direction.

Another case is performing a `#go idle` in a scroll.

Either way, both of these will no longer crash ZZT.

This does not, however, prevent the player from moving onto a
duplicator's destination on the same tick that the duplicator fires
and then the duplicator source ends up moving based on the player's
move direction. That is a different bug which typically doesn't
crash the game.

(by GreaseMonkey)

In particular, this amends ''ElementPushablePush'' to not call itself if deltaX and deltaY are both equal to 0.

===== Implementations =====

  * [[https://github.com/OpenZoo/ClassicZoo/commit/a15cf31301ced8023fe9c00c37e25c45ff0ee8b8|Patch to ZZT 3.2]]