[2.0.20] Construction Bots "Forget" to build one Item

[britfaic]

I've been running into an issue where every so often a Ghost will just *not* be built by the construction bots. I've had it happen with Construction Belts, Beacons, and in my most recent case a Underground Pipe.

I have checked:

1. The Ghost is Light Blue, Indicating a Robot is on the way.
2. The Ghost is In a Logistic Network, with the requested item.
3. There are no errors of an item being unavailable in the logistic network.
4. There are no construction bots stuck in a loop trying to get to the location, but running out of battery before being able to arrive.
5. It is the only item that has a pending construction job.
6. If I build an identical item right next to it, it is fulfilled immediately.
7. If I remove the ghost, and place it back down, it will be built.

[MechBFP]

You have one construction warning in the bottom right (the yellow gear icon) what does it say?

[Genhis]

One of the construction robots has this entity assigned, so the request should be fulfilled eventually.

[britfaic]

You have one construction warning in the bottom right (the yellow gear icon) what does it say?

My Spidertron was waiting on a battery pack. Weirdly, the bug stopped happening once that was fulfilled.

[britfaic]

One of the construction robots has this entity assigned, so the request should be fulfilled eventually.

It was there for about an hour until I gave up and redid the construction.

A few other notes, this kept occuring with several items, until my Spidertron received the battery pack it requested. It also didn't seem to start until the Spidertron request was made in retrospect. When I have time today, I'll try and see if I can reproduce the problem.

[britfaic]

Another thing I noticed, it looks like there are 5 of my construction bots just....zooming around the map holding construction kits. They don't seem to have a destination, they'll go from one corner, to another, never stopping to fix anything. Nothing has been damaged they're running to fix that I can tell, and they don't seem to be in a recharging loop, as they are literally going all over my logistic network.

[boskid]

I decided to do a closer look at what is happening. There are 5 construction robots that are active. One of them has 2 tasks assigned: repair a train then build the pipe-to-ground. All 5 construction robots that are flying have a repair task. They just keep flying towards the train but the train keeps moving around the map in a damaged state so those bots are unable to complete their repair task. Attached is a video where the travel of the damaged train can be seen as well as movement of the 5 construction robots.

[robot256]

This is a perfect example of why the task queue should have a timeout of some sort. The second task is assigned to the robot on the assumption that it will finish the first task and the second task faster than having a different robot come for the second task. But if the first task is delayed for any reason, that assumption no longer holds. Certain types of tasks are more likely to be delayed than others (repairing a vehicle, building an elevated rail, building on ghost landfill or to-be-deconstructed entity).

[Hares]

I decided to do a closer look at what is happening. There are 5 construction robots that are active. One of them has 2 tasks assigned: repair a train then build the pipe-to-ground. All 5 construction robots that are flying have a repair task. They just keep flying towards the train but the train keeps moving around the map in a damaged state so those bots are unable to complete their repair task. Attached is a video where the travel of the damaged train can be seen as well as movement of the 5 construction robots.

After playing with Spidertrons for a while I can confidently say that time needed to repair is not taken into account when a new task is assigned.
So many times I had all but one robots inactive, one repairing spidertron and then that one is picking up task to pick up pentapod eggs laying on the ground, wasting up to 40s of time (time to repair fully-damaged rare spidertron).

[robot256]

You can group the jobs by likelihood of being delayed and decide where to draw the line of when a second job is assigned:

Never delayed: Deconstruction, Upgrading, Rotating, Item delivery/removal to stationary entities

Sometimes delayed: Building entities anywhere

Often delayed: Building on tile ghosts, building elevated rails, building rolling stock, repairing stationary entities

Always delayed: Repairing vehicles, Item/equipment delivery/removal to vehicles

[Hares]

Never delayed: Deconstruction, [...]

Hold my utility science! Deconstruction is often a delayed task as bots can wait for other bots to remove items. Futhermore, if an item is added to entity's inventory, it will delay even further (yes, roboports, i'm speaking of you!).

Also, there's no more rotation tasks; all rotations now happen immediately.

[Hares]

Okay, this time I checked that all construction robots are idle.
Furthermore, these two deconstruction orders can be canceled, and deconstructed again as many times as you want without any effect.

12-22-2024, 00-58-25.png (245.07 KiB) Viewed 329 times

12-22-2024, 00-58-28.png (210.41 KiB) Viewed 329 times

Attaching the savefile with the problem.

Click to expand the recording

[Muche]

122024 Landfill seems to have lost tile data after using the cut tool and cannot be removed / 124155 multi-deconstructing landfill will render bots stuck attempting to deconstruct them might be related regarding the double-deconstruction mark.