When I use vi in gnome-terminal with "set number", I get ______1 I believe it is a bug carried over from xterm, which has been fixed in xterm since xterm works fine now.
I'm not seeing it here with the current version. Can you reproduce this with the Raw Hide version of the vte package?
Try # /bin/vi
The application is sending the control sequence to begin underlining, five or six spaces, and then the number. Unless terminals are supposed to avoid underlining whitespace, this doesn't look like a bug. XTerm on my system is using foreground color to indicate underlined text, so the effect is just not visible. I wasn't able to get XTerm to perform underlining (even starting with the -ulc flag and running "tput smul"), but hanterm and kterm both attempted to, and displayed the same behavior when I repeated the test with vi. I'm inclined to close this as notabug.
It doesn't happen on the Linux console. As I said, it was fixed in xterm a while ago. All the problems on other terms you see may be the similar bug fixed in xterm. Even if you don't think it is a bug in vte, do you think it is a bug in /bin/vi?
Does the console implement underlining using color (which would be hidden when drawing whitespace) or actual underlining? If it's using color, then there's no way to tell that it's not doing the same thing except by examining the sources. I would consider this a bug in 'vi' if the underlining is not supposed to be there. groff handles this properly (for an example, see the underlined text in the groff(1) man page in the "groff Macro Directory" section).
I don't know where the bug is. I do know it is a bug. I can change it to vim if you want.
Regardless of which module the bug belonged to, it now seems to work, fortunately.