Dwarf Fortress Bug Tracker - Dwarf Fortress
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0004600Dwarf FortressDwarf Mode -- Itemspublic2011-05-01 09:302017-11-02 15:44
Toady One 
Windowwswindows 7
0004600: Items frozen in ice are unrecoverable; building on previously iced square crashes game.
I reclaimed a fortress, and all my old fortress's stuff was strewn about, sometimes atop frozen murky pools. Spring rolled around, and I left it there, where it fell into the ice. Another year passed, and the stuff got frozen into the ice. But when the spring thaw came, the stuff was just gone, but still showed on the stocks screen. I later dug out the entire level, floored over the top of the lakes, and then built a building on one of the squares where stuff had been lost, and it crashed my game. I was unable to get my dwarves to dump the items that had been lost despite the tile being accessible.
designate a dump zone or otherwise engineer a square that will freeze to contain an item before freezing. Allow the original ice block to thaw(not sure if this is necessary), and then either allow to refreeze, or empty the water out of the tile. Build on that tile->crash.

It appears as if the game places the items frozen into a container (using DFHack, there was an on_ground flag that was set false). Thawing or mining the ice block there SHOULD unset the on_ground flag and make all the stuff get dumped back out again but it doesn't. The easiest solution would be to have thawing ice check it's square for items that are not set on_ground, and then set them to be on_ground, and do the same for mining out the block.
build, construction, container, crash, dig, Fixed in 0.40.09?, Frozen, ice, thaw
related to 0000895resolved Toady One Items disappear (become invisible) after getting pushed by flowing water, burning in magma, or encased in ice 
has duplicate 0006436resolved Footkerchief Items frozen into ice which then melts vanish until the tile is re-frozen and mined 
Issue History
2011-05-01 09:30JarhynNew Issue
2011-05-01 09:36JarhynTag Attached: construction
2011-05-01 09:36JarhynTag Attached: container
2011-05-01 09:36JarhynTag Attached: crash
2011-05-01 09:36JarhynTag Attached: dig
2011-05-01 09:36JarhynTag Attached: Frozen
2011-05-01 09:36JarhynTag Attached: ice
2011-05-01 09:36JarhynTag Attached: build
2011-05-01 09:36JarhynTag Attached: thaw
2011-05-01 09:37JarhynNote Added: 0017592
2011-06-28 14:10DwarfuNote Added: 0018088
2011-06-28 14:10DwarfuRelationship addedchild of 0000895
2014-02-17 11:18FootkerchiefRelationship addedhas duplicate 0006436
2014-08-14 12:27Toady OneRelationship replacedrelated to 0000895
2014-08-14 12:27Toady OneNote Added: 0029044
2014-08-14 12:40FootkerchiefAssigned To => Footkerchief
2014-08-14 12:40FootkerchiefStatusnew => needs feedback
2014-08-14 12:41FootkerchiefTag Attached: Fixed in 0.40.09?
2017-11-02 15:44LociNote Added: 0036839
2017-11-02 15:44LociStatusneeds feedback => resolved
2017-11-02 15:44LociFixed in Version => 0.40.09
2017-11-02 15:44LociResolutionopen => fixed
2017-11-02 15:44LociAssigned ToFootkerchief => Toady One

2011-05-01 09:37   
Currently I'm testing to see if setting all items to be on_ground is sufficient to make them fall out of the offending square onto the ground
2011-06-28 14:10   
This is mostly a duplicate of 0000895, but the crash on construction is new, so I'm going to make this a child.
Toady One   
2014-08-14 12:27   
0000895 is fixed, but it is hard to say if this is fixed. 0.40.09+ checks would be useful, if possible.
2017-11-02 15:44   
v0.43.05x32: Frozen items do not disappear (0000895), and dwarves correctly move those items before completing a construction in the tile (or suspend the job if unable to move the items).