Is it possible to format the colour of parts of my git branch name inside the prompt?

Question

In my .zshrc file I have the following lines that parse my current git branch and display it in the terminal, the .zshrc file looks like this:

# Load version control information
autoload -Uz vcs_info
precmd() { vcs_info }

# Set up the prompt (with git branch name)
setopt PROMPT_SUBST
PROMPT='%n in ${PWD/#$HOME/~} ${vcs_info_msg_0_} > '


# Format the vcs_info_msg_0_ variable
zstyle ':vcs_info:git:*' formats '(%b)'

So my terminal ends up looking like this:

me in ~/repos/myrepo (feat/MYISSUE-123/fix-the-broken-stuff) >

I would like to modify the script above so MYISSUE-123 has a different colour to the rest of the branch name.
How can I do that?

Answer 1

Try this ... change precmd to:

precmd() {
  vcs_info
  psvar=(${(s:/:)vcs_info_msg_0_})
  # in case there are more than three components:
  psvar[3]=${(j:/:)psvar[3,-1]}  
}

Make sure precmd() is being called prior to each prompt display by adding it to the hook:

autoload -Uz add-zsh-hook
add-zsh-hook precmd precmd

And change PROMPT to:

PROMPT='%n in ${PWD/#$HOME/~} %1v/%F{red}%2v%f/%3v > '

There are some notes about psvar in this answer: https://stackoverflow.com/a/64094551/9307265.
The (s) and (j) parameter expansion flags are documented in the zshexpn man page.

Please let me know if there are any issues.