Crash during battle in editor_game_base.cc:677

[kaputtnik]

This was reported in the forum https://wl.widelands.org/forum/topic/1931/ :

I get a crash in widelands revision #7782. I think I tracked it down to an attack on a certain military site of the blue player. In the savegame at http://pholia.tdi.informatik.uni-frankfurt.de/~philipp/widelands/PkK%202.wgf the attack is already underway, and the crash happens a few tens of seconds after loading the game during combat (loaded savegame three times, each time the crash happened when the first blue soldier's health first went below 50%).

widelands: ../src/logic/editor_game_base.cc:677: virtual void Widelands::EditorGameBase::do_conquer_area(Widelands::PlayerArea<Widelands::Area<Widelands::FCoords> >, bool, Widelands::PlayerNumber, bool, bool, bool): Zusicherung »preferred_player != player_area.player_number« nicht erfüllt.

I could confirm this with r7788 and the attached savegame.

Importance "High" because of crash.

[GunChleoc (gunchleoc)]

It might be the same as this bug:

https://bugs.launchpad.net/widelands/+bug/1251788

Good to have a current savegame though :)

[SirVer (sirver)]

The problem is that a port is finished at (188, 114) for the red player. The code immediately burns it down again and that crashes.

This is the underlying problem:

1) A player never looses land if she has military influence over it.
2) The game does not allow buildings that are on the border - all fields of a building must be fully inside a players land.
3) ports seem to relax assumption 2 (see screenshot). The port only conquers a small amount of land, which does not fully cover it's area.

When the port is finished, the initialization conquers area which checks that all buildings are indeed inside the owned land. Since purples borders cannot move, the port is on the border and gets killed immediately again - and that crashes the assert.

[SirVer (sirver)]

Second screenshot: I manually disabled the check that buildings cannot be on the border - so the port is not burned down after finshing.

I am not sure how to fix this issue.

1) Relax assumption 1) and give the port upon building more conquered land so that when it finishes it does not burn down. This might burn down buildings of the neighbor who looses land without military influence.
2) forbid a port space to be placed there in the first place.

[wl-zocker (wl-zocker)]

So the same as bug 1534962.

See by comment #5 there. I prefer for suggestion 2 (forbid a port space to be placed there in the first place).

[GunChleoc (gunchleoc)]

In the long run, we will want https://bugs.launchpad.net/widelands/+bug/536583

That will be a big change though, so maybe what #5 suggested might be the better option, so we can get the release out.

[TiborB (tiborb95)]

I am attaching a screenshot of two ports with overlapping portdocks - of course portdocks are not visible... for discussion in merge request

[GunChleoc (gunchleoc)]

Fixed in build19-rc1.