[patch] Game crashes while withdrawing convoy

Topic: [patch] Game crashes while withdrawing convoy (Read 2134 times) previous topic - next topic

[patch] Game crashes while withdrawing convoy

December 31, 2009, 03:27:48 pm

This patch fixes two errors, which accessed a convoi_t object after its self destruction.
Ivansanchez posted this error in the Simutrans Experimental topic http://forum.simutrans.com/index.php?topic=4126.0

Re: [patch] Game crashes while withdrawing convoy

Reply #1 – December 31, 2009, 03:54:48 pm

is there a specific procedure to trigger a crash?

Does the attached patch also fix the issue? (I did not like the implicit state-change in laden())

Re: [patch] Game crashes while withdrawing convoy

Reply #2 – December 31, 2009, 04:11:54 pm

Yes, but the savegame is an experimental 7.1 savegame using pak128.Britain.Exp: Withdraw all 800 convoys from line "Newcastle-Cambridge cattle convoy".

No, your patch still continues to use deleted object data in step() after returning from laden(). step() must return before the line switch(state) accesses state. Therefore laden() should not destroy the object, but return a flag, that the object has to be destroyed, which is done best by setting state to SELF_DESTRUCT.

Hm, I should learn to read...
Your patch will delete the convoy in the next step. You should check the impact of this changed behaviour.

Re: [patch] Game crashes while withdrawing convoy

Reply #3 – December 31, 2009, 04:26:55 pm

I see. Thank you very mch. Will be included next year:))

Re: [patch] Game crashes while withdrawing convoy

Reply #4 – December 31, 2009, 09:43:33 pm

The world needs to step convois backwards then. So I added there a fix too.