Ruby Enumerable#sum doesn't work properly with Length objects

[maxp-hover]

I have tested on Sketchup 2023 and 2024 on ARM Mac

The issue is simple to reproduce. Create a few edges, select them, then run the following code snippets in console:

Sketchup.active_model.selection.sum(&:length)

Sketchup.active_model.selection.map(&:length).sum

Only the second returns the correct result. The first just returns the length of the first edge in the selection.

I opened a forum post about this here a few years ago here, but didn't make a bug report for it. https://forums.sketchup.com/t/sketchup-selection-sum-doesnt-work-properly/187279

This is a really easy thing for a plugin / API developer to miss. Clearly there are workarounds, but it's one of those things which can very easily slip under the radar.