Readline control keyboard shortcuts enter weird characters after suspending helix

[vwkd]

Summary

After upgrading to helix 23.03, the control keyboard shortcuts for readline frequently stop working and enter weird characters like 2;5u when suspending helix.

Once broken, the keyboard shortcuts remain broken until the terminal is closed and reopened. When entering a control keyboard shortcut, iTerm2 plays a warning sound and shows a bell icon in the status bar of the terminal.

The issue doesn't occur immediately after the first suspend per session, but a few suspends in. Though it's frequent enough to be reproduced reliably and break in about every session.

The exact mapping of keyboard shortcuts to characters seems to change in each session. The general regex pattern is \d+;\d+u.

There were no issues with the same configuration and helix releases prior to 23.03.

This seems to be unrelated to the shell occuring in both zsh and bash. The only other possible cause could be the last iTerm2 3.4.19 update.

Reproduction Steps

These are approximate steps of reproduction:

1. Open helix hx and do stuff
2. Suspend ctrl + z
3. Write commands and use control keyboard shortcuts like ctrl + p, ctrl + n, etc.
4. If the keyboard shortcuts work, resume helix fg and repeat from 1., at most a few times

I expected this to happen:

Control keyboard shortcuts keep working.

Instead, this happened:

Control keyboard shortcuts eventually stop working and insert weird characters like 2;5u

Here's a screen recording of a clean shell session, opening the helix editor, writing to a file, suspending the editor (ctrl+z), and trying some control keyboard shortcut (ctrl+p). After the second try, the control keyboard shortcuts stop working and instead insert the funny characters 2;5u (ctrl+p), 0;5u (ctrl+n) and 4;5u (ctrl+r).

helix-suspense-ctrl-shortcuts-bug.mov

Helix log

~/.cache/helix/helix.log

2023-04-30T01:04:16.243 helix_vcs [ERROR] Error {
    context: "failed to open git repo",
    source: Discover(
        NoGitRepository {
            path: "/Users/username/foo",
        },
    ),
}
2023-04-30T01:04:16.243 helix_vcs [ERROR] failed to open diff base for /Users/username/foo/bar.txt
2023-04-30T01:04:16.243 helix_vcs [ERROR] Error {
    context: "failed to open git repo",
    source: Discover(
        NoGitRepository {
            path: "/Users/username/foo",
        },
    ),
}
2023-04-30T01:04:16.244 helix_vcs [ERROR] failed to obtain current head name for /Users/username/foo/bar.txt

Platform

macOS 12.6.4

Terminal Emulator

iTerm2 3.4.19

Helix Version

helix 23.03 (3cf0372)