NPC reading crash

[CHJKDM51]

Describe the bug

I told NPC to study from a book and left my base for a couple game days. Now when I'm trying to approach my base it crashes the game.

Steps To Reproduce

Steps to reproduce the behavior:

1. Load save.
2. Walk south-east.
3. Get crash.

Expected behavior

Versions and configuration

• OS: Windows
  • OS Version: 10.0 1903
• Game Version: 0.D-9511-g32e0c35 [64-bit]
• Graphics Version: Tiles
• Mods loaded: [
  Dark Days Ahead [dda],
  Disable NPC Needs [no_npc_food]
  ]

Additional context

1)Ingame message:

DEBUG : Lost target of ACT_READ

FUNCTION : void activity_handlers::read_finish(player_activity*, player*)
FILE : src/activity_handlers.cpp
LINE : 2910

2)Error message:

CRASH LOG FILE: config/crash.log
VERSION: 0.D-9511-g32e0c35
TYPE: Signal
MESSAGE: SIGSEGV: Segmentation fault
STACK TRACE:
@0x5D3A25[cataclysm-tiles.exe+0x1D3A25]
@0x5D44F2[cataclysm-tiles.exe+0x1D44F2]
SMPEG_error+0x4B034@0xFBAEB0[cataclysm-tiles.exe+0xBBAEB0]
_C_specific_handler+0x98@0x7FFAB6398048[msvcrt.dll+0x28048]
_chkstk+0x11F@0x7FFAB71611FF[ntdll.dll+0xA11FF]
RtlRaiseException+0x399@0x7FFAB712A289[ntdll.dll+0x6A289]
KiUserExceptionDispatcher+0x2E@0x7FFAB715FE6E[ntdll.dll+0x9FE6E]
@0xB6BAE3[cataclysm-tiles.exe+0x76BAE3]
@0x4505C0[cataclysm-tiles.exe+0x505C0]
@0xCCD82A[cataclysm-tiles.exe+0x8CD82A]
@0xB865DD[cataclysm-tiles.exe+0x7865DD]
@0xB99B54[cataclysm-tiles.exe+0x799B54]
@0xB9D601[cataclysm-tiles.exe+0x79D601]
@0x70D582[cataclysm-tiles.exe+0x30D582]
@0x70ED1C[cataclysm-tiles.exe+0x30ED1C]
IMG_LoadWEBP_RW+0x62F11C@0x16DBE3C[cataclysm-tiles.exe+0x12DBE3C]
@0x4013ED[cataclysm-tiles.exe+0x13ED]
@0x4014FB[cataclysm-tiles.exe+0x14FB]
BaseThreadInitThunk+0x14@0x7FFAB6AC7BD4[KERNEL32.DLL+0x17BD4]
RtlUserThreadStart+0x21@0x7FFAB712CED1[ntdll.dll+0x6CED1]

3)log files:
crash+debug.zip

4)save:
https://drive.google.com/open?id=12Kt93brFDjesQ-DXdfv_fr5_okba2aml

P.S. Any advice how to skip that error and continue playing? If it is possible in the first place.

[Funguss]

Have you updated the game? It sounds like this:
#35593
Related to this:
#35352
If so, then the best way to deal with it is probably to long-range teleport to their location, talk to the NPC(s) then tell them to stop their current activity. You can get them reading again afterwards and it should be fine.

[CHJKDM51]

Yes I'm updating game almost every day IRL.
Long range teleport to npc location gives same crash.

[Vollinger]

Try replacing save\Knoxville\o.0.0 with this one, I changed ACT_READ to ACT_NULL, should make your crashy readers back to followers. Have a backup, just in case.
Knoxville_stop_reading.zip

Log says it's version 0.D-9511, over a month old now, sure you're not launching some old misplaced exe or something?

[CHJKDM51]

Log says it's version 0.D-9511, over a month old now, sure you're not launching some old misplaced exe or something?

It was actually 9918 (latest version at the moment of posting). I assume "game version" and "build" is not the same?

Editing save fixed it, thanks!

[ghost]

This can be closed now?

[eltank]

I can reproduce this bug by asking an NPC to read a book, then waiting half an hour. Same debug message, then segfault. I'll try to figure out which build introduced the bug.

[Funguss]

Hmm... No such problems for me. What version are you using?

[eltank]

Build 9907 is fine. Build 9908 triggers the bug.
https://ci.narc.ro/job/Cataclysm-Multijob/9908/
Looks like #35538 has something to do with it.

[eltank]

A couple more observations:

1. I cannot reproduce this with a new game world at 9908 or 9928
2. If I load a save made after updating to 9928 in my old game world then downgrading to 9900 I also get a crash
   So I probably need to debug my save file and see what got messed up. But I expect that other players who have been playing experimental for a while to also experience this bug under certain (unknown) conditions after updating their game.

[eltank]

Figured it out. If your pre-9908 save has any NPCs that are reading and you update the game you may get a crash when they finish the activity (like the OP). The workaround is to cancel the reading activity (either by talking to the NPC or hacking the save file). Reading activities that are started after updating seem fine.

[Funguss]

Yeeeees. You probably should have looked at the issues I mentioned in the first comment. In the first issue linked I had commented about this and explained how to sort it out, bar save editing. That is precisely why I linked to it. I suggested teleporting in order to deal with NPCs who are too far away for you to stop.
I hope you didn't spend too much time on this. Do have a look at the linked issues in future, generally speaking they're included for your benefit.

[eltank]

Thank you Funguss, your post was very helpful; I just failed to scroll down and read the pertinent information. Thus I ended up re-discovering what was mentioned in #35593.
Oh well, at least this provides some confirmation. I do believe this bug can be closed since it's infeasible to fix but there is a workaround.

[Funguss]

No worries, it happens to us all. Yeah, the issue is only really going to hit those updating their game with an ongoing world in which an NPC is reading. I doubted anybody else would have it but here we are! There will probably be another bug report about this in a month or two or something ludicrous whether this gets closed or not. As it only occurs to updated worlds I do believe this should be closed, plus it's easy enough to workaround.

[ghost]

Yep, depending on how prevalent and serious a bug is that has been caused by saving during a period of bugged experimental, a fix can be made to try and repair the save on load, but I expect this particular one to be minimal and have no further occurences after a while.