layout_python_hatch: direnv config plugin for python projects using hatch

layout_python_hatch.sh

# shellcheck shell=sh enable=all
# ~/.config/direnv/lib/layout_python_hatch.sh
# direnv config plugin for hatch
# https://direnv.net

fail() {
    [ "$#" != "0" ] || set -- FAIL
    echo >&2 "$@"
    return 1
}

layout_python_hatch() {
    unset VIRTUAL_ENV PYTHON
    env=${1-default}

    [ -e pyproject.toml ] ||
        fail "no pyproject.toml"

    grep -q '^\[tool\.hatch[].]' pyproject.toml ||
        fail "no [tool.hatch] or [tool.hatch.*]"

    has hatch ||
        fail "hatch not available; uv tool install hatch?"

    hatch env create "$env" > /dev/null 2>&1 ||
        fail "hatch env create $env: exit $?"

    VIRTUAL_ENV=$(hatch env find "$env") ||
        fail "hatch env find $env: exit $?"

    PYTHON=${VIRTUAL_ENV}/bin/python3
    export PYTHON VIRTUAL_ENV
    PATH_add "${VIRTUAL_ENV?}/bin"
}