0005937: Hauler with bin wanders in circles - Dwarf Fortress Bug Tracker

Notes
(0022659) Footkerchief (manager) 2012-05-22 07:06	Reminder sent to: MinsEcho Please upload a save demonstrating this problem to http://dffd.wimbli.com/ [^] and post the link here.

(0022671) MinsEcho (reporter) 2012-05-22 13:53 edited on: 2012-05-22 13:53	I was just able to reproduce this. F2 zooms to the guilty hauler. Careful of the strange mood dwarf nearby, he's about to go insane and is carrying a battleaxe. Actually, the first just stopped, but someone else is doing the same thing just to the north. http://dffd.wimbli.com/file.php?id=6366 [^]

(0022684) SirPenguin (reporter) 2012-05-22 21:41	I have the same issue. My guy is in a narrow hallway pacing back and forth carrying a barrel with "Store Item in Barrel" job. The barrel has a bunch of plump helmets in it. I think he harvested them from the farm. Designating the area around him to be dug out caused him to move a bit further...then he repeated his little dance. After a few repeats of this he eventually freed himself. Save: http://dffd.wimbli.com/file.php?id=6371 [^]

(0022692) vidboi (reporter) 2012-05-23 15:48 edited on: 2012-05-23 16:05	Had the same issue, and I believe that I've found the cause and a temporary solution before it's fixed. It seems to occur with bins and barrels assigned to stockpiles (those with numbers). If the stockpile gets filled whilst the bin is being moved it can't be placed back there and the dwarf wanders in circles. Creating a new stockpile for the item doesn't work either, but dumping what's in the existing stockpile to make way for it seems to resolve the issue. I'm not certain on this; although the bin was eventually moved to the stockpile it was not by the same dwarf who was walking in circles with it (they got thirsty and dropped it to get a drink). If anyone else could test this to see if it works i'd be grateful. update: Appears that it doesn't work. I got another dwarf doing the same thing with the same stockpile but making space in the stockpile didn't stop it. After stopping due to thrist another dwarf promply picked it up and took it to it's destination successfully, just as before. The next test is to see if deleting the stockpile the bin is assigned to has any effect.

(0022707) Footkerchief (manager) 2012-05-24 12:03	ag posted details at 0005948.

(0022710) ag (reporter) 2012-05-24 12:31	This bug is not about the crash, it is about dwarves 'walking in a small circle'; therefore renaming it is incorrect.

(0022711) Footkerchief (manager) 2012-05-24 13:21	This report was about both the circle-walking and the subsequent crash. Do you have reason to believe that they're separate problems?

(0022712) ag (reporter) 2012-05-24 13:43	I can see no way a failure to check a pointer for NULL can cause circle-walking, since in the only situation when that check would make a difference, omitting it leads to an immediate crash. The crash is caused by forbidding the bin (or otherwise causing the item to be removed from the job), whether there is any circle-walking going on, or not. Of course, I don't have the source code, only the stack backtrace and disassembly to base my opinion on.

(0022744) ag (reporter) 2012-05-27 08:58	Felt like investigating the actual running around behavior. It seems what happens is this: Hauling code re-evaluates which item is closest to get every N frames, instead of once for every item; this means that if actually getting to it requires temporarily moving away due to obstacles in the way, a different item can be chosen as target at that point. If trying to get to it in turn causes the unit to move back to where it started, the loop repeats.

(0022745) Quietust (reporter) 2012-05-27 09:01	This behavior reminds me of 0000596, an old bug from 0.31.12 and earlier, where [BUILDINGDESTROYER:2] diplomats could get stuck "dancing" in circles for what was probably the exact same reason.

Issue History
Date Modified	Username	Field	Change
2012-05-21 22:06	MinsEcho	New Issue
2012-05-22 07:06	Footkerchief	Note Added: 0022659
2012-05-22 07:06	Footkerchief	Tag Attached: AWAITING UPDATE
2012-05-22 13:53	MinsEcho	Note Added: 0022671
2012-05-22 13:53	MinsEcho	Note Edited: 0022671	View Revisions
2012-05-22 15:04	Footkerchief	Tag Detached: AWAITING UPDATE
2012-05-22 21:41	SirPenguin	Note Added: 0022684
2012-05-23 15:48	vidboi	Note Added: 0022692
2012-05-23 16:05	vidboi	Note Edited: 0022692	View Revisions
2012-05-23 18:05	SirPenguin	Tag Attached: Save Included
2012-05-24 12:00	Footkerchief	Relationship added	has duplicate 0005948
2012-05-24 12:01	Footkerchief	Summary	Hauler with bin wanders in circles, gamecrash if interfered with => Crash when container is detached from "Store in Bin/Barrel" job
2012-05-24 12:02	Footkerchief	Issue Monitored: Toady One
2012-05-24 12:03	Footkerchief	Note Added: 0022707
2012-05-24 12:31	ag	Note Added: 0022710
2012-05-24 13:21	Footkerchief	Note Added: 0022711
2012-05-24 13:43	ag	Note Added: 0022712
2012-05-24 14:47	Footkerchief	Summary	Crash when container is detached from "Store in Bin/Barrel" job => Hauler with bin wanders in circles
2012-05-24 15:11	Footkerchief	Relationship replaced	related to 0005948
2012-05-27 08:58	ag	Note Added: 0022744
2012-05-27 09:01	Quietust	Note Added: 0022745
2012-05-27 11:48	Footkerchief	Relationship added	related to 0000596
2012-05-27 18:19	Toady One	Status	new => resolved
2012-05-27 18:19	Toady One	Fixed in Version	=> Next Version
2012-05-27 18:19	Toady One	Resolution	open => fixed
2012-05-27 18:19	Toady One	Assigned To	=> Toady One
2012-06-10 13:41	Footkerchief	Relationship added	related to 0005997
2014-12-30 20:24	Footkerchief	Relationship added	has duplicate 0006054