Clarification on DEC mode 2031 support and behavior in Ghostty

[dmmalam]

Does Ghostty supports DEC mode 203 and queried like:

printf '\e[?2031$p'

I was under the impression tha the expected response is either "[?2031;1$y" (light mode) or "[?2031;2$y" (dark mode), depending on the current appearance, but I consistently receive the 2 regardless of:

• The macOS global appearance (light or dark),
• Whether Ghostty has both light and dark themes available or only one,
• Whether using the latest stable or tip build.

Here's how I'm currently querying it:

printf '\e[?2031$p'; dd bs=1 count=32 2>/dev/null < /dev/tty | cat -v

And this is the kind of the script I’m aiming to use:

printf '\033[?2031$p' > /dev/tty
resp=$(dd bs=1 count=32 2>/dev/null < /dev/tty)

case "$resp" in
  *"[?2031;1\$y"*) echo light ;;
  *"[?2031;2\$y"*) echo dark  ;;
  *)               echo not-support ;;
esac

Any ideas?
Thanks!

[jcollie]

Mode 2031 is used to turn on async mode change reports in the future. If you want to query the status now you need to send CSI ? 996 n.

See:

https://github.com/contour-terminal/contour/blob/f3c3334aa5c861348c5bbe8ffe572c872eef2e08/docs/vt-extensions/color-palette-update-notifications.md

[jcollie]

Also, mode 2031 is turned on with CSI ? 2031 h and turned off with CSI ? 2031 l. Not with $p.

[dmmalam]

Thanks, that works.