Factorio Forums

Cross-posted to https://www.reddit.com/r/factorio/comme ... _landfill/

Reproduction steps

1. Grab 25 personal construction robots and go somewhere over water, where only personal robots are active. Ensure your personal roboports are switched off, to allow time to perform the steps here.
2. Place a 25 landfill in water on Nauvis, by hand.
3. Deconstruct all the landfill using ctrl+x.
4. Turn your roboports on. All landfill is successfully deconstructed. Turn your roboports off again.
5. Place 25 landfill in water on Nauvis, by hand again.
6. Deconstruct all the landfill using ctrl+x.
7. Deconstruct all the landfill again using ctrl+x. Note the double red X deconstruction mark.
8. Turn your roboports on. Your bots will be prevented from deconstructing the landfill.

This can be resolved by either

1. Slowly deconstructing the landfill by hand, or
2. Bringing in more bots to bear on the situation.

You can do this with a different number of robots and landfill, as well as marking the landfill more than twice. The key is that times_marked*landfill_count has to be more than the number of robots you have available to deconstruct. Presumably this has something to do with landfill only being deconstruct-able once all buildings on top of it are gone, and landfill marked for deconstruction is somehow counting as if it were a building on top of landfill. If you have more than enough bots to cover the equation above, then bots will be stuck attempting to deconstruct until another bot comes out, does nothing, and sets it free to do its job.

Attached is a save file currently stuck in this position - but not the minimal reproducible case.

Hmm, I've observed something similar with space platform tiles with a double X:
The ones at the top where ctrl-x'd, the ones at the bottom alt-d'd, and the ones in the middle were both ctrl-x'd and alt-d'd (i.e. cut and marked for deconstruction).
Of course those tiles shouldn't be removed as it would create a disjoint platform, so it's not a bug here, just strange that there are two X's.

Unrelated, but thank you for teaching me alt-d. I've been doing ctrl+x + esc for years now, because I didn't know there was a simple "Just murder these things". It's going to take a while to reprogram the muscle memory though.

Relatedly: I suspect the space platform case is the same root cause (placeable ground can, through some mechanism, be marked for deconstruction multiple times), but is asymptomatic, because space construction is effectively "What if we had infinite, immediate construction robots".

jbirch wrote: Tue Dec 10, 2024 3:34 pm Unrelated, but thank you for teaching me alt-d. I've been doing ctrl+x + esc for years now, because I didn't know there was a simple "Just murder these things". It's going to take a while to reprogram the muscle memory though.

I also do ctrl-x esc, as it doesn't touch trees or cliffs (which make the game look nicer!)

Ah, and alt-d doesn't trigger this bug! Presumably because alt-d is simply "murder all that's here", whereas ctrl-x is "tell me something about what's here so I can stamp it somewhere else".

Edit: Nor does a deconstruction planner with landfill selected.

jbirch wrote: Tue Dec 10, 2024 3:44 pm Ah, and alt-d doesn't trigger this bug! Presumably because alt-d is simply "murder all that's here", whereas ctrl-x is "tell me something about what's here so I can stamp it somewhere else".

For the platform thing, using ctrl-x or alt-d twice only gave me one X, it's only if I use both do I get two X's.

But for your case, it's only giving two X's if you do ctrl-x twice?

But for your case, it's only giving two X's if you do ctrl-x twice?

That's correct. Ground can be marked multiple times (not just twice!) with ctrl-x - though only two red Xs will ever show. For example, If you have 75 construction robots, but use ctrl-x three times on 25 landfill, this will also trigger the issue.

I can also trigger a double-X on space platforms with ctrl-x, but I need to be a bit sly to do it because they deconstruct so fast. If you mark an otherwise entirely surrounded area with ctrl-x (IE, that cannot actually be actioned, because it would leave a hole), you can mark it again with a second ctrl-x. However, as I speculated above, this doesn't trigger the deconstruction issue once you "open that up" by deconstructing platforms around it.

"Undo" of the case above removes the whole larger outer deconstruct (IE, the only one that makes sense), but leaves the inner, doubled deconstruct as a deconstruct.

Another "Undo" results in the (extremely helpful!) dialog of "you're gonna undo something completely unrelated". This seems pretty consistent with hypotheses we've shared here.

See also: Re: 122426: [2.0.20] Construction Bots "Forget" to build one Item. Recording, logs, and save file attached