TL;DR
Make pipes circuit-readable.What?
Let the circuit network read from a pipe to get its (or its entire fluid segment's) contents. Maybe symmetric to belts and allow both modes, but I'm not picky.Why?
Fluid tanks are readable, but adding the extra volume of fluid tanks to a pipeline can be really undesirable (slows pull rates to a trickle in low-volume cases). This is especially applicable when meta-automating liquids (e.g. using chem plant Set Recipe feature).Meta-automating solids doesn't have this issue as every entity in their network can be read, and this asymmetry is pretty inelegant.
Here's an actual use case with deadlocks that seem effectively unresolvable without this feature: https://old.reddit.com/r/factorio/comme ... ll/lttruu6