Helix leaves terminal in a bad state when killed

[ccmtaylor]

Summary

After killing helix because it was stuck (I inadvertently caused a global search in my entire home directory), the editor left the terminal (iTerm 2 on macOS) in a bad state: entering normal characters work, but control keys (e.g. C-a, C-e) echo escape codes instead of moving the shell cursor.

Possibly related to #2250, however mouse movement doesn't spam the terminal for me.

Reproduction Steps

reproduction recording:

I tried this:

1. hx
2. killall hx (either in a separate terminal, or within helix with :sh)
3. try to enter control characters in the terminal

I expected this to happen:

I expected the terminal to work normally after exiting Helix.

Instead, this happened:

the terminal echoes control characters. Trying to reset the terminal using reset, or starting and exiting Helix cleanly, does not return things to normal.

Helix log

~/.cache/helix/helix.log

2023-04-14T14:09:58.690 helix_view::clipboard [DEBUG] Using pbcopy+pbpaste to interact with the system clipboard
2023-04-14T14:09:58.693 helix_tui::backend::crossterm [DEBUG] The keyboard enhancement protocol is supported in this terminal (checked in 2.146462ms)
2023-04-14T14:09:58.694 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:09:59.092 helix_term::application [DEBUG] received editor event: IdleTimer
2023-04-14T14:09:59.766 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:00.168 helix_term::application [DEBUG] received editor event: IdleTimer
2023-04-14T14:10:01.103 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:01.303 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:01.519 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:01.629 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:01.823 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:01.926 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:02.064 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:02.231 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:02.732 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:02.823 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:05.958 helix_view::editor [ERROR] editor error: no such command: 'killall'
2023-04-14T14:10:05.959 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:07.799 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:08.201 helix_term::application [DEBUG] received editor event: IdleTimer
2023-04-14T14:10:08.375 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:08.479 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:08.624 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:08.625 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:09.872 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:09.873 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.063 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.065 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.298 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.299 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.416 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.417 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.616 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.618 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.696 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.698 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.829 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.829 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:10.979 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:10.980 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:11.187 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:11.188 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:11.296 globset [DEBUG] built glob set; 0 literals, 14 basenames, 1 extensions, 0 prefixes, 0 suffixes, 0 required extensions, 0 regexes
2023-04-14T14:10:11.297 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-04-14T14:10:11.984 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0

Platform

macOS

Terminal Emulator

iTerm 2 (Build 3.4.19)

Helix Version

helix 23.03 (3cf0372)

[the-mikedavis]

When Helix is killed we don't restore the terminal (exit raw mode, disable mouse capture, etc.). We can't do anything about this for hard kills (kill -9) but we could add a handler for sigterm that restores the terminal and exits gracefully. Kakoune and Vim both do this.

[sbromberger]

Does using the reset command at the command prompt fix things? This isn't a solution, but it might be a workaround until Helix can restore the terminal.

[ccmtaylor]

@sbromberger no, reset does not restore the terminal behaviour. I don't actually know any way to get things into a good state apart from closing the window.

@the-mikedavis I think that sounds like a good approach 👍

[tommyscholly]

Is the solution to this not just adding SIGTERM to the application handle_signals (and to the signals passed into the application)

If so, I can make that PR quickly.

[the-mikedavis]

Yep, we need to add SIGTERM to the list of signals we handle:

helix/helix-term/src/application.rs

Line 233 in c49faf5

let signals = Signals::new([signal::SIGTSTP, signal::SIGCONT, signal::SIGUSR1])

Then add a block in handle_signals that restores the terminal and breaks the event loop so that we exit gracefully.

We could handle SIGINT the same way (that's what Kakoune does: https://github.com/mawww/kakoune/blob/a4918f934ceb8c36ab398c0c973174ac17fc8600/src/main.cc#L764-L765).