Copying text from Alacritty doesn't work intermittently

[maddiemort]

I find myself not being able to copy text some of the time from inside Alacritty.

I have the following keybindings in ~/.config/alacritty/alacritty.yml:

key_bindings:
  - { key: Key3, mods: Alt, chars: "#" }
  - { key: C, mods: Control|Shift, action: Copy }
  - { key: V, mods: Control|Shift, action: Paste }

When I press ctrl-shift-C:

• Some of the time nothing at all is copied.
• Some of the time something garbled is copied (e.g. some text that's on screen somewhere but not what I selected, some text that's only part of my selection, some text that crosses the boundary of my selection)
• Some of the time my selection is copied correctly.

Most of the time I'm inside a tmux session when I use Alacritty, but I've reproduced this just fine outside of tmux, so I don't think it's strictly being caused by tmux.

My Alacritty config file sets $TERM to xterm-256color, and my tmux config sets:

set  -g default-terminal "tmux-256color"
set -ga terminal-overrides ",xterm-256color:RGB"

As a result, inside tmux, my $TERM is set to tmux-256color, and outside it's set to xterm-256color.

My tmux config also sets:

set -g mouse on

System

OS: Linux (NixOS)
Version: alacritty 0.8.0
Linux/BSD: X11, none+bspwm with picom compositor

Logs

Keyboard and bindings: alacritty --print-events: alacritty-event-log.txt

[chrisduerr]

You use mouse mode in tmux, so do you actually use the Alacritty selection?

[maddiemort]

Not when I'm using tmux - it's not always possible, because I need the selection to wrap inside the tmux pane. I've been working under the assumption that copying a tmux mouse mode selection with Alacritty is intended to work, because of both the fact that it works sometimes on this machine, and because it worked/works all the time on previous/other machines (mainly macOS that I can remember).

[chrisduerr]

I've been working under the assumption that copying a tmux mouse mode selection with Alacritty is intended to work

That is entirely up to tmux and has nothing to do with Alacritty.

You said that you can reproduce it completely outside of tmux, is that reliable? Also is there any other application running at that time?

[maddiemort]

You said that you can reproduce it completely outside of tmux, is that reliable?

No, but the problem isn't reliable either.

Also is there any other application running at that time?

No.

That is entirely up to tmux and has nothing to do with Alacritty.

Understood. I'll investigate whether making changes to my tmux config makes a difference to the problem.

[chrisduerr]

Are you certain this has been reproduced outside of tmux in the past? While the Alacritty window you copied from was still open?

[maddiemort]

Are you certain this has been reproduced outside of tmux in the past?

I'm not 100% sure, but I'm reasonably sure. I distinctly remember wondering if it was tmux's fault, and trying it in a new Alacritty window that wasn't running tmux, and it still not working. I'm pretty sure I've done that more than one time.

While the Alacritty window you copied from was still open?

Yes.

[chrisduerr]

You say that you tried it in a new Alacritty window, which would indicate that this is somewhat reliable to reproduce? Or why is it that you were able to immediately test without tmux, but reproducing reliably isn't possible?

[Warepire]

I've been getting similar effects on Linux, also intermittently. When it happens it sometimes copies a few chars, sometimes one or more lines, is consistent for the window after it happens, never seen it recover. Usually works fine in a new window. Copying with mouse always works 100%.

I don't use tmux at all.

Alacritty version: HEAD commit as of writing (ed76efe)

OS: Arch Linux, kernel 5.13.12-arch1

Shell: zsh
Possibly more common to happen while using vim or bat (https://github.com/sharkdp/bat), and after.

[maddiemort]

Sorry I haven't replied, I've been very busy.

You say that you tried it in a new Alacritty window, which would indicate that this is somewhat reliable to reproduce? Or why is it that you were able to immediately test without tmux, but reproducing reliably isn't possible?

It doesn't necessarily mean that it's reliable to reproduce. It just means that sometimes when this has happened to me, I've immediately opened a new Alacritty window and tried it there, and sometimes that also exhibits the same incorrect behaviour. Seems to me that that's just because it's an intermittent problem, so when it happens to me once there's a nonzero chance that it will happen if I try again.

When it happens it sometimes copies a few chars, sometimes one or more lines, is consistent for the window after it happens, never seen it recover.

This is consistent with my experience.

Shell: zsh

I also use zsh.

Possibly more common to happen while using vim or bat (https://github.com/sharkdp/bat), and after.

I also use bat, and I use nvim.

[chrisduerr]

Copying with mouse always works 100%.

What do you mean by that? Are you saying vi mode copying doesn't work, or do you mean using the keyboard to copy the mouse selection?

Have any of you two noticed that this issue was more/less common in previous versions?

[Warepire]

Copying with mouse always works 100%.

What do you mean by that? Are you saying vi mode copying doesn't work, or do you mean using the keyboard to copy the mouse selection?

Using the actual mouse to select text and copy is not affected, just vi mode copy. It does not matter which mode (normal or vi) when using the mouse, it will always work.

Have any of you two noticed that this issue was more/less common in previous versions?

I have not noticed any change in frequency since I started using Alacritty around 3 months ago.

[maddiemort]

Have any of you two noticed that this issue was more/less common in previous versions?

I have been using Alacritty for several years, and as far as I remember didn't encounter this issue more than a few months before now. HOWEVER, it's only on about that same timescale that I switched to using NixOS full time, before which I was using macOS. I'm pretty sure, though, that I didn't have this issue before when I used NixOS or Manjaro on-and-off for periods of time.

[maddiemort]

Using the actual mouse to select text and copy is not affected, just vi mode copy.

You may not be describing the same issue, in that case - I never use Alacritty's vi mode, so by definition I have only ever experienced this when using my mouse to select text and copy it.

[chrisduerr]

Yeah, sounds like two different issues. Especially if you can reliably reproduce it maybe open a separate issue @Warepire, but if it's just an "every once in a while" thing in vi mode that suggests the issue might not necessarily be with Alacritty.

[chrisduerr]

I have been using Alacritty for several years, and as far as I remember didn't encounter this issue more than a few months before now.

"A few months" seems like a timeframe that should be fairly easy to test with a downgrade, right?