Created attachment 547536 [details] video describing the problem Hello, sorry for the poor description of the bug, but I have no idea where's it's coming from. I couldn't reproduce by using x11-terms/st or another editor (tried with busybox vi or simply cat). This is by using emacs -Q -nw (so no surprises with config files), and I tried with removing all the urxvt Xresources from the X server. Every 6 spaces, the seventh doesn't display and I get a sudden jump of two when typing the eigth (makes me think something is wrong with tabs or maybe the terminfo). Attached is a video of the bug (sorry for displaying problems, this is 4:4:4 chroma subsampling).
Looks like this is a known problem: https://bbs.archlinux.org/viewtopic.php?pid=1018150#p1018150 Does starting the terminal with "urxvt +ptab" fix it for you?
Yes, it does! Too bad I didn't land on this page during my search. Incidentally, even after reading the manpage, I still don't understand it fully.
Maybe worthwhile to report this to emacs or (and?) rxvt upstream. I fear there isn't much we can do about this at the distro level.
rxvt-unicode is kind of dead, but emacs has a chance. Anyway, just leaving the bug open is already plenty.
I was on the verge of reporting it, but the more I look at it, the more it doesn't look like a bug; more like a strange default.