console doesn't support xterm-256color's "Esc E" for newline #14603

When I try to use the control sequence \EE ("Esc E") on a recent WSL,

ganesh@DESKTOP-VCELNMA:~$ echo -e 'foo\EEbar'
foobar

Whereas in native Linux terminals I've tried, and PuTTy, I get:

[ganesh@paxton:~]$ echo -e 'foo\EEbar'
foo
bar

This has recently become a problem for me because it's listed as the sequence for a newline (nel) for xterm-256color in recent versions of the ncurses terminfo database (follow the link to xterm-new and then xterm-p370). It's also documented as an Xterm control sequence here.

From browsing the changelog I think this was added in early 2021 and has recently made its way into Ubuntu - it's not there in Ubuntu 20.04 and is there in Ubuntu 22.04. One way to see if it's listed on a particular machine is to run infocmp -x -1 xterm-256color | grep nel.

It goes wrong for me in practice with tools that use the Haskell terminfo library, which has this code to look up how to produce a newline. If nel isn't listed, then the fallback option works fine, but if it is listed then it tries to use \EE as instructed. This means that tools like ghci (the Haskell REPL) do this:

ghci> 5+510

instead of the expected.

ghci> 5+5
10

It can be reproduced without running a Linux shell by this .cmd file (rename to remove the .txt after downloading). You can see other control sequences do work by changing the E on the final echo line, for example changing it to an M invokes ri (scroll backwards). Of course without the WSL angle there's no particular reason to expect a random xterm control sequence to work in console.

Apologies if I've got completely the wrong end of the stick here about the problem, I didn't know anything much about how terminals actually communicate until I started digging into this problem. Now that I understand the issue better there should be various workarounds available (like setting TERM to something different).