Watsit said:
Plus, portals represent a cut in space and/or time, so the shortest path using a portal isn't a straight line, but a cut/segmented path that only appears connected from certain viewpoints.

it'd still be a straight, unbroken line, though, there's just some perspectives where it'd seem otherwise.

it's like if you could point a super laser pointer that ignores all matter and only cares about the topology of space. in euclidian space no matter where you position those points there's always one and exactly one way to position the laser so it crosses any two points in space. once you start introducing non-euclidian topology there are going to be situations where not all pairs of points are colinear and/or situations where a single pair of points share multiple lines.

dba_afish said:
it'd still be a straight, unbroken line, though, there's just some perspectives where it'd seem otherwise.

I'd say it's the other way around. If I take a piece of paper and rip it, then draw a line that goes up to the cut on one side and another line that continues from the other side of the cut, that wouldn't be a straight unbroken line even if the paper and line appeared straight and unbroken to some observer at certain viewpoints. Space (the paper) is broken, even if it can be aligned to appear continuous from an observer inside the space. It'd be a broken line that can appear unbroken, rather than an unbroken line that can appear broken.