Immediate freeze upon launching most scenarios

[kostmo]

Starting scnenarios through the menu or through the command line with --scenario causes the program to freeze. pkill swarm must be executed in the terminal to recover. E.g. this one freezes:

stack run -- --scenario data/scenarios/creative.yaml

It seems that not all scenarios freeze, however; these ones work:

stack run -- --scenario data/scenarios/Tutorials/scan.yaml
stack run -- --scenario data/scenarios/Challenges/2048.yaml

[byorgey]

Issue 1000! @kostmo is the winner! 🎉

[byorgey]

Is this on the current main branch? I can't reproduce this.

[kostmo]

Observed at commit 68c992a on the main branch. Tried the following without success:

• stack clean
• git clean -fdx
• Reboot computer

It seems that the freeze is not absolute; if I wait long enough, the world UI will display, but will then still be unresponsive to keyboard input.

[byorgey]

I still cannot reproduce. Maybe some of your data/save/history files got corrupted or huge somehow, and swarm is taking a very long time trying to read/process it somehow?

[kostmo]

In case it is relevant, here's what I encountered before the freeze issue:

kostmo@dell-ubuntu:~/github/swarm$ stack run
Warning: while processing Tutorials/00-ORDER.txt: files not listed in 00-ORDER.txt will be ignored
  - install.yaml
Failed to load scenarios: Aeson exception:
Error in $.solution: Could not parse term: 1: Unbound variable install
kostmo@dell-ubuntu:~/github/swarm$ find -name install.yaml
./.stack-work/install/x86_64-linux-tinfo6/3598b35d16175b2123168d7c37dbbc360ad9ba49ad215feda9c6c5d30c8c8528/9.2.5/share/x86_64-linux-ghc-9.2.5/swarm-0.2.0.0/scenarios/Tutorials/install.yaml
kostmo@dell-ubuntu:~/github/swarm$ git clean -fdx
Removing .hie/
Removing .stack-work/
Removing stack.yaml.lock
kostmo@dell-ubuntu:~/github/swarm$ find -name install.yaml
kostmo@dell-ubuntu:~/github/swarm$
stack run -- --scenario data/scenarios/creative.yaml

I have since nuked the .local/share/swarm directory, but am still hitting the freeze issue.

For the creative scenario, it freezes for about 15 seconds, then shows the main UI. CPU is pegged at 100% throughout. Memory appears to be stable.

[kostmo]

More observations:

• I've jumped around through recent commits, have not identified any one commit as the culprit.
• Anecdotally, commit 4c2f1e6 exhibits the issue, whereas 097ff5a does not.
• The duration of the freeze varies. Sometimes it lasts 90 seconds, or 20-30 seconds, sometimes less than 10, sometimes only a couple seconds. I've realized that the freeze does seem to be finite, (almost?) all of the time. The record that I've had the patience to wait for is 3 minutes pegged at 100% before subsiding.

[kostmo]

Ok, I've pinpointed the problem to commit 3087021 (#975). The parent commit (dd28529) does not exhibit the problem.

[kostmo]

I've reproduced the problem on two different machines, with Ubuntu 21.10 and 22.04.1.

[byorgey]

I was finally able to reproduce this. Strangely, it seems turning off optimizations with --fast (stack build --fast && stack exec swarm ... ) makes the freeze go away. Note that I normally build with --fast because it makes compilation much faster and has never seemed to affect the speed of the resulting executable in any way, which is why I was initially unable to reproduce. @xsebek , have you encountered this? What options do you use when building with cabal?

[byorgey]

The warning about install.yaml and parse error is not relevant, that's due to the stack bug where it doesn't clean out the directory holding data files. That often happens to me when switching branches, the only solution is to stack clean --full (or just rm -rf .stack-work) and rebuild.

[byorgey]

So far I only get the freeze with GHC 9.2.5, with optimizations on. I tried with GHC 9.4.2 and GHC 9.2.4, and both seem to work fine with no freeze.

[xsebek]

I encountered it too, with the default Cabal options and GHC 9.2.5.

No idea what is going on there, it can’t be the game logic because that would have effected integration tests. 🤔

The only times I remember the game freezing were:

• in ranching/GoL scenarios with a lot of busy robots
• when opening modals with absurdly long list of widgets (messages and that bug with space under help)

But this happened to me opening Creative scenario that has no robots and no big lists in TUI. 🤔