--no-strip-ansi prints ANSI codes and garbles output

[srithon]

This flag was introduced in PR #784, after a commit in PR #739 unconditionally stripped ANSI codes from stdin. PR #739 was made in response to issue #689; in order to prevent the display from being garbled by incorrect ANSI code handling, we opted to simply strip ANSI codes from the input entirely. The implementation in PR #784 (and my own draft implementation in PR #782) simply undo that stripping behavior without addressing the underlying issues from #689, resulting in strange outputs in certain cases. Below is a minimal example which results in garbled output on my machine in Kitty, Alacritty and st.

#!/bin/sh

green=$(tput setaf 2)
reset=$(tput sgr0)

{
  echo "Option 1"
  echo "Option 2"
  echo "${green}Option 3${reset}"
} | gum filter --no-strip-ansi

Here are recordings for each tested terminal. Note that Kitty was a lot worse than the others; interestingly, when I tried using asciinema to record Kitty's output, the recording showed the same 2m result as the other terminals; to show what it actually looked like on-screen I had to use a screen recording.

1. Kitty
2. Alacritty
3. st

[caarlos0]

oh, I see, lemme fix that!

[caarlos0]

to resolve this properly I think we need 2 things:

1. matching et al against the ansi-stripped string (just implemented this in a local branch)
2. when printing the matched options, we'll need to deal with ansi sequences when highlighting as well - gonna try to implement this into x/ansi

[caarlos0]

is this what you expect would happen?

[srithon]

is this what you expect would happen?

This looks perfect, thank you! I'll test it out and let you know if I find anything else.

[joshmedeski]

Hey, when using my sesh, my session manager I've added the --no-strip-ansi flag and it's allowing my icons' colors to render properly, but when I type a filter it's skipping the first two letters of the matching result ("downl" only highlights "wnl").

I'm guessing it's related to this feature, any ideas what's causing it? When the icons are remove from the script the matching result works as expected.

[meowgorithm]

@joshmedeski Hey! And chance you can provide a one-liner we can use to reproduce the bug you're seeing?

[joshmedeski]

Once you install sesh you can run this command:

sesh connect "$(sesh list -i | gum filter --limit 1 --fuzzy --no-sort --placeholder 'Pick a sesh' --prompt='⚡' --no-strip-ansi)"

The -i flag for the sesh list -i command is the most important part to recreate the issue.

And this is how I render icons.

[srithon]

Here's a reproducible example of the problem which doesn't require installing sesh.

• 90 is the color code for gray
• the second printf argument is the settings icon

printf '\033[%dm%s\033[39m %s' 90  Downloads | gum filter --no-strip-ansi

[caarlos0]

oh, yeah, emoji grapheme, will fix! thanks for the reproducible btw!

[caarlos0]

this should do the trick: #799