Black on selection

black_selection.sh

#!/usr/bin/env bash
# Original Source: https://blog.godatadriven.com/black-formatting-selection
# This is a modified version of
# https://gist.github.com/JDusub83/ba2848d71644f4c3496def4c1a1d9fc8
# 
# changes:
# - Added debugging prints, permissioning/cleanup, and also a bugfix for
# selecting whole file.
# - Now the original file can only be modified from black to run without errors.
# - Added support to black pyproject.toml - https://black.readthedocs.io/en/stable/pyproject_toml.html
# - Fixed sed syntax
# 
# This script will:
# 1 - extract the contents of the indicated lines from the indicated file
# 2 - put the extracted content in a temporary file
# 3 - try to use black to format the temporary file
# 3.1 - if it is not possible to reformat the temporary file,
#       then it will end execution without modifying the original file.
# 4 - delete the indicated lines from the original file.
# 5 - inject the formatted code in the original file
#
#
# Note:
# for this to work, you must select a valid code snippet that
# can be valid python code alone, that is, without depending on other codes


set -x

# Inputs
black=${1?param missing to an absolute path to black executable} # absolute path to black
config_path=${2?param missing to an absolute path that contains the pyproject.toml file with black configurations} # absolute path to pyproject.toml with black configurations
input_file=${3?param missing to an absolute path to a file to extract lines}
start_line=${4?param missing to the first line number}
end_line=${5?param missing to the first line number}

black_config_file="$config_path//pyproject.toml"

if [ ! -f "$black_config_file" ]
then
  echo "The directory $config_path does not exists or not contains pyproject.toml file";
  exit 1;
fi


# Read selected lines and write to tmpfile
selection=$(sed -n "$start_line, $end_line p; $((end_line+1)) q" < "$input_file")
tmpfile=$(mktemp)
chmod 700 "$tmpfile"  # Only user can read/write (not execute), for security

# Write to tmpfile and apply Black formatting
echo "$selection" > "$tmpfile"


# Print tmpfile for debugging
echo -e "Before formatting code:\n---------------\n$(cat "$tmpfile")\n---------------"


# run black and if it's successful, update the original file
if $black --config "$black_config_file" "$tmpfile";
then

  # Print tmpfile for debugging
  echo -e "Reformatted code:\n---------------\n$(cat "$tmpfile")\n---------------"


  # Delete original lines from input file
  sed -i "$start_line,$end_line d" "$input_file"


  # sed doesn't work on empty file, just assume if start line is 1, that the
  # whole file was selected.
  if [ "$start_line" == 1 ]
  then
    # sponge wasn't originally installed on my Mac... brew install moreutils
    cat "$tmpfile" "$input_file" | sponge "$input_file"  # prepend
  else
    sed -i "$((start_line-1)) r $tmpfile" "$input_file"
  fi

  # Cleanup tmpfile
  rm -f "$tmpfile"
fi

Pycharm External Tools configuration: