[2.0.69] Circuit Controlled Splitter with Input Priority Disregards Priority for First Tick

[vitharr]

A circuit controlled Splitter set to Set Filter with a static Input Priority (untested with circuit controlled Input Priority), on every belt tier except Basic (15/second), will allow both inputs to flow for the first tick, rather than only the prioritized input, even when provided only 1 tick of control signal. Issue is most noticeable when both inputs are saturated.

Expected behavior under 1 tick conditions: One set of items from the prioritized input

Observed behavior under 1 tick conditions: Two sets of items, one from either inputs

Expected flow behavior while filter is enabled: Prioritized input flows freely

Observed behavior while filter is enabled: Both inputs flow at the same time for the first tick, delaying the prioritized input until the belt ahead has space for another set, then the prioritized input flows freely

[boskid]

Given there is no clear save file provided showing the issue i am going to claim that this is Not a bug due to inherent delay it takes for a circuit network to process signals and take effects.

[vitharr]

Isolated the build in editor for logging and save file attachment here

Also a blueprint available here: https://factoriobin.com/post/qpv27i

Anticipated result would be drawing only from the priority belt for all belt tiers with a 1 tick command

Live result in 2.1.8 experimental is currently both belts pulled from at all tiers except yellow

[eugenekay]

I experimented with this step-by-step quite a bit, and I was not able to find anything "wrong". It looks like the Fast/Express/Turbo splitters internal "buffer positions" are being used to move items directly to the Output lane - they briefly have a content of 22 Items, vs the standing-still 18 Items. This happens during the tick where the Control Behaviour is toggled off by the circuit.

Whereas the yellow Belts/Splitter take an extra Tick to move the items far enough to reach the Internal Buffer; this makes it happen on the next tick where the Control Behaviour has taken effect.