Fix error setting PROMPT_COMMAND in bash

[rocha]

The PROMPT_COMMAND environmental variable is setup incorrectly by pazi:

$ unset PROMPT_COMMAND
$ eval "$(pazi init bash)"
$ echo $PROMPT_COMMAND
__pazi_add_dir;$PROMPT_COMMMAND   # should be __pazi_add_dir;
$ PROMPT_COMMAND="__pazi_add_dir;" eval "$(pazi init bash)"
$ echo $PROMPT_COMMAND
__pazi_add_dir;$PROMPT_COMMMAND  # should be __pazi_add_dir;

[euank]

I'm curious what specific issue you ran into. Did your shell actually give you an error with things as they are?

It would be nice to add a regression test for what you ran into.

It might also be worth fixing upstream (since those couple lines were taken from fasd): https://github.com/whjvenyl/fasd/blob/3e6fd486b182224369ac312435fc02fc8c6c2f09/fasd#L172-L176

[euank]

I think that escape is still needed.

With this change, it prints the error:

bash: eval: line 47: syntax error near unexpected token `;'
bash: eval: line 47: `    *__pazi_add_dir;*) ;;'

[euank]

After poking around a bit more, I think there's a deeper problem that this doesn't fix.

Any existing stuff in prompt command appears to just be being overwritten regardless.

I'm basing this specifically on the following:

$ cat ~/.bashrc
foo() {
  echo "Foo ran"
}

set -x
PROMPT_COMMAND="foo"

eval "$(pazi init bash)"
set +x

$ bash
+ PROMPT_COMMAND=foo
++ pazi init bash
+ eval '
__pazi_add_dir() {
    # TODO: should pazi keep track of this itself in its datadir?
    if [[ "${__PAZI_LAST_PWD}" != "${PWD}" ]]; then
        pazi visit "${PWD}"
    fi
    __PAZI_LAST_PWD="${PWD}"
}

case \$PROMPT_COMMAND in
    *__pazi_add_dir\;*);;
    *) PROMPT_COMMAND="__pazi_add_dir;${PROMPT_COMMMAND}";;
esac

pazi_cd() {
    if [ "$#" -eq 0 ]; then pazi view; return $?; fi
    local res; 
    res="$(__PAZI_EXTENDED_EXITCODES=1 pazi jump "$@")"
    local ret=$?
    case $ret in
    90) echo "${res}";;
    91) cd "${res}";;
    92) echo "${res}" && return 1;;
    93) return 1;;
    *) echo "${res}" && return $ret;;
    esac
}
alias z='\''pazi_cd'\'''
++ case \$PROMPT_COMMAND in
++ PROMPT_COMMAND='__pazi_add_dir;'
++ alias z=pazi_cd
+ set +x


$ echo $PROMPT_COMMAND 
__pazi_add_dir;

In the above, the foo function isn't called, either with or without the changes in this PR.

[rocha]

@euank The problem is that the script returned by pazi init bash is supposed to prepend __pazi_add_dir to the expanded value of $PROMPT_COMMAND. Since it is not expanding, any previous value of the variable is lost. For example:

$ echo $PROMPT_COMMAND
history -a; history -n;
$ eval "$(pazi init bash)"
$ echo $PROMPT_COMMAND
__pazi_add_dir;$PROMPT_COMMAND

[euank]

@rocha Does this change actually end up fixing the issue for you, as in does it sill execute your existing prompt command's contents as you expect?

Per my previous comment, on my system (bash 4.4.12) it seems to not respect any existing prompt command with or without this PR.

I'm a bit confused as to exactly why this PR doesn't work for me since it seems right. Before diving too far into that, I want to make sure we're at least observing the same thing.

[LinuxMercedes]

While attempting to reproduce all this with pure bash, I discovered why pazi clobbers PROMPT_COMMAND: I misspelled the variable name. Neat!

[rocha]

@euank yes, the fix works for me, provided I remove the extra M 😅

I am running bash 4.4.12.

I have found that following this guide and using the associated linter helps avoiding bash quoting headaches:
https://github.com/anordal/shellharden/blob/master/how_to_do_things_safely_in_bash.md

[euank]

Indeed, it turns out that extra M was tripping me up here too. Thanks for catching the other issue here and submitting a pr!

I hope you don't mind that @LinuxMercedes is picking this up... Trust me, you probably don't actually want to wade into the integ test harness