xl console with replace escapes does not inform terminal apps that it is restricted

[ben-grande]

Qubes OS release

Qubes OS 4.2

Brief summary

The patch 1009-tools-xenconsole-replace-ESC-char-on-xenconsole-outp.patch is nice, but it doesn't inform applications the terminal is dumb.

Steps to reproduce

1. sudo xl console QUBE
2. Try to use backspace, zsh command-line completion, zsh syntax highlighting

Expected behavior

Backspace works, colors are not applied.

Actual behavior

Backspace doesn't work, escape characters messes the screen, pain with Zsh completion and syntax highlighting.

Additional information

Now it is set to TERM=vt220, it would be better if it was set to dumb when replace escapes is used.

I have accessed to terminals that inform they are vt220 and most of the escape sequences work there, so I cannot and should not disable capabilities because of that.

tty is /dev/hvc0, although it seems super specific to a console, I believe it is best to use TERM to inform the correct capabilities of the terminal.

https://invisible-island.net/ncurses/terminfo.src.html#tic-dumb

When it is dumb, backspace works.