PROMPT_COMMAND clobbers $? about jump

[gsamokovarov]

Can you give a bit more context? I'm still being able to access $? for the return value in bash as usual.

[greygore]

Yes, that confused me too. I assume PROMPT_COMMAND is executed in a subshell which preserves the value of $? outside of that. The problem comes inside that PROMPT_COMMAND subshell. If I want to alter my bash prompt in response to the success or failure of the last command, I need to do is store that return value to prevent clobbering it myself:

function my_prompt_func() {
    local code=$?
    local dir=$(pwd)

    if [ $? -eq 0 ]; then
        PS1="$dir ✔ $"
    else
        PS1="$dir ✕ $"
    fi
}

PROMPT_COMMAND=my_prompt_func

(Or a real life example)

Of course, when I add eval "$(jump shell bash) it changes that to PROMPT_COMMAND="__jump_prompt_command;$PROMPT_COMMAND", which means that $? inside of my_prompt_func is the exit code of __jump_prompt_command and not the command last executed by the user.

Since it looks like you're just hooking into that to adjust the score, it seems like you could reorder those PROMPT_COMMANDs to put __jump_prompt_command last, which is what I've done in my workaround. Alternately, you could return the original exit code from _jump_prompt_command, or preserve the last exit code in an environmental variable, but those both seem unnecessary

[gsamokovarov]

I get you now! Will reorder it for the next version. Haven't thought that someone may require the return value somewhere in PROMPT_COMMAND.

Thanks for the detailed report!

[gsamokovarov]

Hey @greygore, can you try the changes in f124fa4 and see whether they work for you? A lot of tools inject themselves into the beginning of PROMPT_COMMAND and if I inject myself last I have to be weary of ;;.