Bat: Pass -S option to less if wrapping is explictly disabled

[Lazza]

What version of bat are you using?

bat 0.15.4

Describe the bug you encountered:

I have a file with long lines (longer than 100 characters). If I call bat like this, lines are wrapping:

bat --wrap=never Vagrantfile

Describe what you expected to happen?

I expect the lines not to wrap.

How did you install bat?

On Ubuntu, I used the DEB package provided in the GitHub releases. On macOS, I used Homebrew.

The following system information is for Ubuntu, but I see the same behavior on macOS Catalina as well.

---

system

$ uname -srm
Linux 5.4.0-47-generic x86_64

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04
Codename: focal

bat

$ bat --version
bat 0.15.4

$ env

bat_config

bat_wrapper

No wrapper script for 'bat'.

bat_wrapper_function

No wrapper function for 'bat'.

$ /usr/bin/fish --login -i -c functions cat

# Defined in - @ line 1
function cat --wraps=bat --description 'alias cat=bat'
bat  $argv;
end

tool

$ less --version
less 551 (GNU regular expressions)

[sharkdp]

If I call bat like this, lines are wrapping

Well, the lines will still be wrapped by your terminal emulator (or the pager). But you shouldn't see a continued line in the sidebar:

[Lazza]

Oh... now I understand. Could it be possible to set the -S option to less if the following conditions are met?

• the user did not set a custom value for --pager
• the user added --wrap=never

If I try this, it seems to do what I expect it to do:

bat --wrap=never --pager="less -SR" a.txt

[sharkdp]

That sounds like a nice feature request actually. @eth-p: what do you think?

[gahag]

Can I work on this?

[eth-p]

That sounds like a nice feature request actually. @eth-p: what do you think?

Sounds useful.

I'm concerned making the change might be disruptive for people who set --wrap=never in their config file without --pager, though.

But at the same time, I'm also not a fan of adding --wrap=absolutely-never... Maybe try it as a default, but be open to making it opt-in if we get enough bug report issues about it in the next release?

[sharkdp]

But at the same time, I'm also not a fan of adding --wrap=absolutely-never... Maybe try it as a default, but be open to making it opt-in if we get enough bug report issues about it in the next release?

Good idea, yes.

@gahag: Can I work on this?

Yes, please! :smile:

Be warned though: we have to deal with multiple versions of less on the user side. This has been problematic in the past. If we make changes to the command-line options that are passed to less, I would like to see the new feature tested with a number of different less versions (at least 487, 551 and the latest version. You can get a bigger picture by searching through some of the recent bug reports where people often post their less version).

[gahag]

@sharkdp thanks for the heads up. Is there an existing method or tool for testing with many less versions, or that would have to be improvised?

[sharkdp]

We don't have an automated way of doing that yet, unfortunately. We'll have to find someone with the respective version of less or install these versions ourselves. I do have access to 487 and 551 - on Linux. We also had problems with bugs in less on Windows :-/

[gahag]

I have access to Arch Linux and FreeBSD machines, where the less versions are 551 and 530. Also, I just noted that a Debian docker image has the 487 version. I would be willing to implement this feature and test against these versions, is that ok? Also, is 551 the latest version?

[sharkdp]

I would be willing to implement this feature and test against these versions, is that ok?

Yes - of course.

Also, is 551 the latest version?

I don't think it is, no.

[gahag]

Ok. I'll have a go at it tomorrow, hope it will be done by the middle of the day.