It's never the terminal emulator (whether GNOME Terminal or any other terminal app) that decides what to print on a backspace. The only thing it does is that it tells over the tty line that the backspace key has been pressed.
It's the remote party, which could be the application running inside (such as "bash", "vim" etc.), or the kernel's cooked mode handler code (e.g. if you're running "cat") that decides what to tell to the terminal how to update its canvas (such as e.g. retreat the cursor by one, print a space, and retreat the cursor again -> to achieve the visual effect of deleting the last single-cell character). The terminal emulator has no other choice than to blindly execute these instructions and update its canvas accordingly. (It cannot even tell if this requested display update was in any way connected to the backspace keypress or not, nor should it care.) That's just the way this whole architecture looks like. You have to file a bugreport against whichever applications where backspace doesn't work as you'd expect it. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-terminal in Ubuntu. https://bugs.launchpad.net/bugs/2051371 Title: Backspace in gnome-terminal often deletes cluster Status in gnome-terminal package in Ubuntu: New Bug description: If I have ខែ្ (U+1781 U+17c2 U+17d2) in the terminal and press backspace, the first backspace deletes U+17c2 U+17d2 so that I'm left with ខ (U+1781). Instead it should only delete the last codepoint, U+17d2. If I have ខែ (U+1781 U+17c2) a backspace deletes only U+17c2, similarly if I have ខ្ (U+1781 U+17d2) where the backspace deletes U+17d2. Further investigations show that backspace often deletes the entire cluster, i.e. diacritic(s) plus the base character, for example with x̣́ (U+0078 U+0301 U+0323) where a backspace deletes all three codepoints. gnome-terminal should only delete the last codepoint [1]. A real live example where this behavior is problematic is when using ibus-keyman with the Khmer Angkor keyboard [2]. When typing xEjmr the expected output is ខ្មែរ (U+1781 U+17d2 U+1798 U+17c2 U+179a). Keyman does some reordering while typing to put the codepoints in a standardized order. Because gnome-terminal lacks support for surrounding text, the codepoints have to be deleted by emitting several backspace keypresses. Because of the deletion of the cluster the result in gnome-terminal is ្មែរ (U+17d2 U+1798 U+17c2 U+179a). [1] https://github.com/keymanapp/keyman/wiki/Backspace-and-cluster-deletion [2] https://github.com/keymanapp/keyman/issues/10481 ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: gnome-terminal 3.44.0-1ubuntu1 [modified: usr/libexec/gnome-terminal-server] ProcVersionSignature: Ubuntu 6.5.0-14.14~22.04.1-generic 6.5.3 Uname: Linux 6.5.0-14-generic x86_64 ApportVersion: 2.20.11-0ubuntu82.5 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Fri Jan 26 12:21:42 2024 InstallationDate: Installed on 2022-04-12 (653 days ago) InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Beta amd64 (20220329.1) SourcePackage: gnome-terminal UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-terminal/+bug/2051371/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
