Another what the heck moment in Fedora 43. In Gnome-terminal (only, not xterm), hitting 'Delete' in vim insert mode no longer deletes characters to the left of the cursor, only characters to the right. Delete is generating ^? in both gnome-terminal and xterm, and Delete works to delete characters in vim in g-t on the ':' command prompt.
Whatever vim / gnome-terminal combined stupidity this is, I want it gone. Now.
Well I have an answer to my vim and gnome-terminal thing and the answer is 'set noxtermcodes'. The other answer is that both gnome-terminal and vim have what I think are bugs that collude to allow this situation to happen. You can argue about exactly whose fault this was, but that's not really productive.
Well I guess there is a workaround in gnome-terminal by changing what it generates for 'Delete' (the key) to 'escape sequence'. What a mess.
Let me guess: historical termcap. (-:
Might be Joy+Horton #vi, but my first guess is #termcap.
The way that termcap, and even terminfo, handle switchable stuff like this is truly terrible, because it simply does not fit their model. They're poor on input sequences anyway.
#FreeBSD still uses termcap(5), pretty much the only operating system left that does, and its manual page discusses how one might want to be compatible with AT&T #Unix S5R2 in the future.
Chris Siebenmann
JdeBP