is it possible to apply code format before git diff command

Question

I was working on a old repo, I have config my editor to auto apply black and isort while save, but the repo code not. So while I try to diff, there will always be so much diff message to views. So I wonder if it possible to apply black and isort while call git diff, So I can only check the logic different, but not the format.

Answer 1

You can use the options to avoid spaces/eol change. Try git diff -w but there are others. Check git help diff

Answer 2

This feature was rejected from black (see https://github.com/psf/black/issues/245) but on Unix systems you can use the below black-diff function to get the basic functionality (allowing to compare a single file against the latest version, or two revisions of a single file):

Check changes since last commit:

black-diff test.py

Compare two versions of a file between branches:

black-diff main:test.py feature_branch:test.py

The function itself (you can add it to your ~/.bashrc for convenience):

black-diff () {
  if [[ $# -eq 0 ]]; then
    echo "Please provide path to the modified file (or two revisions of a file) to compare"
    return 1
  fi
  if [[ $# -eq 1 ]]; then
    # compare latest revision against current version
    cat $1 | black -q - | diff --color -u <(git show "$(git branch --show-current):$1" | black -q -) -
  else
    # compare two revisions
    git show $1 | black -q - | diff --color -u <(git show $2 | black -q -) -
  fi
}

Answer 3

There is a diff tool based of syntax that support over 20 programming languages (Python is one of them). This tool is experimental and you can review in Github, DiffStatic.