inserting linebreaks to cli_abort error messages

[selkamand]

Thanks for all your work on this incredible package!

I just noticed that single newline (\n) characters are seemingly ignored in cli_abort but double newlines (\n\n) are respected.

1. Is this expected behaviour?
2. What is the recommended way to insert a single linebreak into a cli_abort error message?

Reprex (using version cli_3.5.0) :

library(cli)

# single newline character doesn't affect error message
cli_abort("Hello\nWorld")
#> Error:
#> ! Hello World

#> Backtrace:
#>     ▆
#>  1. └─cli::cli_abort("Hello\nWorld")
#>  2.   └─rlang::abort(...)

# two next to each other lead to rendered linebream
cli_abort("Hello\n\nWorld")
#> Error:
#> ! Hello
#> 
#> World

#> Backtrace:
#>     ▆
#>  1. └─cli::cli_abort("Hello\n\nWorld")
#>  2.   └─rlang::abort(...)

^{Created on 2023-01-06 with reprex v2.0.2}

[gaborcsardi]

In general, you can insert line breaks with \f: https://cli.r-lib.org/reference/inline-markup.html#wrapping

❯ stop(cli::format_error("foo\fbar"))
Error: foo
bar

rlang::abort() seems to strip the \n unfortunately, I am not sure why:

❯ rlang::abort("foo\nbar", use_cli_format=FALSE)
Error:
! foo
bar
Run `rlang::last_error()` to see where the error occurred.

❯ rlang::abort("foo\nbar", use_cli_format=TRUE)
Error:
! foo bar
Run `rlang::last_error()` to see where the error occurred.

Somewhat related cli issue: #460.

[gaborcsardi]

Soon there will be much better ways to nest cli components (e.g. formatted output) into other components (e.g. bullet list).