Correct return value in BASH prompt

Question

This is part of a .bashrc file that sets a prompt, on a Ubuntu 19.10 machine:

# Terminal tab name in gnome-terminal or Guake
PROMPT_COMMAND='echo -ne "\033]0;$(basename ${PWD})\007"'

GIT_PS1_SHOWCOLORHINTS=yes
RET=\$?
source /usr/lib/git-core/git-sh-prompt

if [ "$color_prompt" = yes ]; then
    color_reset=$(tput sgr0)
    color_bold=$(tput bold)
    color_white=$(tput setaf 7)
    color_jobs=$(tput setaf 7)
    color_user=$(tput setaf 3)
    color_dir=$(tput setaf 4)
    color_load=$(tput setaf 5)
    color_succeed=$(tput setaf 2)
    color_fail=$(tput setaf 1)
    sep=$(tput setaf 7)\)
    PS1="${color_user}\u${sep}\[\D{%T}\]${sep}${color_reset}\$(__git_ps1)${color_dir}\W${color_reset}${sep}\`if [[ ${RET} == 0 ]]; then echo \"${color_succeed}0\"; else echo \"${color_fail}${RET}\"; fi\`${color_white}${sep}${color_reset}\$ "
else
    PS1="\u${sep}\[\D{%T}\]${sep}\$(__git_ps1)\W${sep}\`if [[ ${RET} == 0 ]]; then echo \"0\"; else echo \"${RET}\"; fi\`${sep}\$ "
fi

and this is an example of the command line in use:

snim2)10:39:53)dirname)0)$ cd scratch
snim2)10:39:54)scratch)0)$ git init
Initialised empty Git repository in .../scratch/.git/
snim2)10:39:56) (master)scratch)0)$ asdasda
asdasda: command not found
snim2)10:40:05) (master)scratch)1)$ $?
127: command not found
snim2)10:40:10) (master)scratch)1)$ 

As you can see, when the return code of a command is non-zero, it appears as 1) in the prompt, rather than showing the correct return code -- in this case 127). How can this be fixed?

Answer 1

You do:

..$(__git_ps1)...\`if [[ $? == 0 ]];

The $? is going to be return status of __git_ps1 not the last executed command on command line.

Try saving the exit return value in the first command substitution block right away:

if [ "$color_prompt" = yes ]; then
    color_reset=$(tput sgr0)
    color_bold=$(tput bold)
    color_white=$(tput setaf 7)
    color_jobs=$(tput setaf 7)
    color_user=$(tput setaf 3)
    color_dir=$(tput setaf 4)
    color_load=$(tput setaf 5)
    color_succeed=$(tput setaf 2)
    color_fail=$(tput setaf 1)
    sep=$(tput setaf 7)\)
else
    color_reset=
    color_bold=
    color_white=
    color_jobs=
    color_user=
    color_dir=
    color_load=
    color_succeed=
    color_fail=
    sep=\)  # remove the braces...
fi

# note the quotes - "" expand at setting time, '' expand at runtime
PS1=
PS1+="${color_user}\u${sep}\[\D{%T}\]${sep}${color_reset}"
PS1+='$('
   PS1+='ret=$?; '  # first thing we do - save the exit return value
   PS1+='__git_ps1; '
   PS1+='printf "%s" "'
      PS1+="${color_dir}\W${color_reset}${sep}"
      PS1+='"; '
   PS1+='if ((ret == 0)); then '
       PS1+='printf "%s" "'
          PS1+="${color_succeed}"  # expand variable on assignment side
          PS1+='0"; '  # this looks strange. Just print first the color, then $ret...
   PS1+='else '
      PS1+='printf "%s" "'
           PS1+="$color_fail"
           PS1+='$ret"; '
   PS1+='fi '
PS1+=')'
PS1+="${color_white}${sep}${color_reset}"
PS1+='\$ '  # note - this is *not* "\$ "