Not Enough Fuel To Refuel: Trigger-Happy Edition

That's what it should look like. But it's a static image.

What should not be happening, is the topmost alert disappearing and reappearing roughly twice a second.

I have reason to believe it's connected to the fact that there are other fuel stations with fuel, they're just unreachable to these haul trucks (across a suspension bridge, or through the narrow isle between those tanks and the tracks). Maybe there's enough of them, and far enough away, that the pathing system is taking long enough to verify unreachability that the alert times out? Because the alert is simply timing out, rather than being attached to the vehicles in question, and waiting to be cleared by said vehicle, like the ones two below- for Haul Truck Has No Fuel?

I will also note that the number on the "struggling to find a destination" error is also constantly changing, for the same reason- time-out rather than cleared. Maybe a cyclical time-out that only activates if the vehicle in question has entered an "idle, not waiting for path, no destinations to seek paths to" state? Or having the truck simply clear the error on its own once it realizes it no longer needs to path to the destinations it cannot reach, but waiting for that to clear them, rather than letting the error flicker because the swamped pathing system is taking too long to verify it still can't reach them?

Update 4.2 | v0.8.6c (b612).

Save is attached, though this is far from the first time this kind of thing has happened- ever since I started in Update 2. I seem to remember seeing something similar in previous changelogs, though they were for errors that recurred so fast they were never truly either present or absent.

If you load my save and need the issue to persist for more than a minute, pause the first tanker train. It's loaded with diesel. This issue only arose because my refinery isn't large enough to handle much diesel generator action, and said generators get priority. (Incidentally, this mine also controls a good 47MW of load in the form of the bauxite processing plant, so fuel problems at this mine tend to self-regulate... though I do need to keep an eye on the gold volume in the cargo ships when relying on this effect for long, if that runs out the whole factory is dead in the water)

Issue persists in v0.8.7d (b619)... though this occurrence is a little less dramatic, and far easier to reproduce:

(Incidentally, that truck trapped itself through dumping, should that be considered a bug...?)

Every single one of those red lines goes to a fuel station that's approximately across the map, completely full of fuel, and completely reachable (except from the tiny island the truck has trapped itself on), and yet the "Truck has no fuel" error (and the more global "Not enough fuel to refuel a vehicle" error) appears and disappears once or twice a second, generating a constant stream of alerts (and sounds) from the same, single issue, when it really ought to have one alert that simply persists. Like "Truck is struggling to find a destination it can reach", that error is steady.

Especially in this particular dumping project (and the many like it I've performed, dumping a single-deep layer over terrain prepared by a stacker tower), wherein all it has to do is wait for another truck to rescue it by dumping nearby... There are ten of them on the job.

Since the issue seems to be connected to the pathing system in at least some way, reproduction may require a wide region of pathability reachable from either the vehicle or the valid fuel station. It likely also requires multiple fuel stations for the truck to choose from, thereby requiring multiple (failed) pathing requests to verify that the error still applies.

I would also like to note that when a boxed-in, fuel-seeking truck (as in my less-dramatic occurrence) is unboxed (whether by other vehicles performing work or by Unity recovery), it travels obstinately to the first fuel station it found a valid path to, not the nearest, making it a rather arbitrary selection that's usually across the map, even if there's a valid, reachable, available station basically right next door.