Re: [PATCH] completion: prompt: use generic colors

[Justin Donnelly <justinrdonnelly@gmail.com>]

On Fri, Aug 26, 2022 at 8:08 PM Felipe Contreras
<felipe.contreras@gmail.com> wrote:
>
> When the prompt command mode was introduced in 1bfc51ac81 (Allow
> __git_ps1 to be used in PROMPT_COMMAND, 2012-10-10) the assumption was
> that it was necessary in order to properly add colors to PS1 in bash,
> but this wasn't true.
>
> It's true that the \[ \] markers add the information needed to properly
> calculate the width of the prompt, and they have to be added directly to
> PS1, a function returning them doesn't work.
>
> But that is because bash coverts the \[ \] markers in PS1 to \001 \002,
> which is what readline ultimately needs in order to calculate the width.
>
> We don't need bash to do this conversion, we can use \001 \002
> ourselves, and then the prompt command mode is not necessary to display
> colors.
>
> This is what functions returning colors are supposed to do [1].
>
> [1] http://mywiki.wooledge.org/BashFAQ/053
>
> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> ---
>
> FTR, it's possible zsh will implement these \001 \002 markers too, so
> there would be no need for different behavior depending on the shell.
>
>  contrib/completion/git-prompt.sh | 19 +++++++------------
>  t/t9903-bash-prompt.sh           |  8 ++++----
>  2 files changed, 11 insertions(+), 16 deletions(-)
>
> diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
> index 1435548e00..01bd807657 100644
> --- a/contrib/completion/git-prompt.sh
> +++ b/contrib/completion/git-prompt.sh
> @@ -96,9 +96,7 @@
>  #
>  # If you would like a colored hint about the current dirty state, set
>  # GIT_PS1_SHOWCOLORHINTS to a nonempty value. The colors are based on
> -# the colored output of "git status -sb" and are available only when
> -# using __git_ps1 for PROMPT_COMMAND or precmd in Bash,
> -# but always available in Zsh.
> +# the colored output of "git status -sb".
>  #
>  # If you would like __git_ps1 to do nothing in the case when the current
>  # directory is set up to be ignored by git, then set
> @@ -255,12 +253,12 @@ __git_ps1_colorize_gitstring ()
>                 local c_lblue='%F{blue}'
>                 local c_clear='%f'
>         else
> -               # Using \[ and \] around colors is necessary to prevent
> +               # Using \001 and \002 around colors is necessary to prevent
>                 # issues with command line editing/browsing/completion!
> -               local c_red='\[\e[31m\]'
> -               local c_green='\[\e[32m\]'
> -               local c_lblue='\[\e[1;34m\]'
> -               local c_clear='\[\e[0m\]'
> +               local c_red=$'\001\e[31m\002'
> +               local c_green=$'\001\e[32m\002'
> +               local c_lblue=$'\001\e[1;34m\002'
> +               local c_clear=$'\001\e[0m\002'
>         fi
>         local bad_color=$c_red
>         local ok_color=$c_green
> @@ -564,11 +562,8 @@ __git_ps1 ()
>                 b="\${__git_ps1_branch_name}"
>         fi
>
> -       # NO color option unless in PROMPT_COMMAND mode or it's Zsh
>         if [ -n "${GIT_PS1_SHOWCOLORHINTS-}" ]; then
> -               if [ $pcmode = yes ] || [ -n "${ZSH_VERSION-}" ]; then
> -                       __git_ps1_colorize_gitstring
> -               fi
> +               __git_ps1_colorize_gitstring
>         fi
>
>         local f="$h$w$i$s$u$p"
> diff --git a/t/t9903-bash-prompt.sh b/t/t9903-bash-prompt.sh
> index 6a30f5719c..594042f562 100755
> --- a/t/t9903-bash-prompt.sh
> +++ b/t/t9903-bash-prompt.sh
> @@ -13,10 +13,10 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
>  . "$GIT_BUILD_DIR/contrib/completion/git-prompt.sh"
>
>  actual="$TRASH_DIRECTORY/actual"
> -c_red='\\[\\e[31m\\]'
> -c_green='\\[\\e[32m\\]'
> -c_lblue='\\[\\e[1;34m\\]'
> -c_clear='\\[\\e[0m\\]'
> +c_red='\001\e[31m\002'
> +c_green='\001\e[32m\002'
> +c_lblue='\001\e[1;34m\002'
> +c_clear='\001\e[0m\002'
>
>  test_expect_success 'setup for prompt tests' '
>         git init otherrepo &&
> --
> 2.37.2.351.g9bf691b78c.dirty
>

This appeared to work for me with a quick test. I probably don't have
any sway, but FWIW I would use it.

Justin