Only format git diff (similar to clang-format-diff)

[Rikorose]

Relevant yapf issue: google/yapf#190

It would be really helpfull to only format code that was changed which also helps to minimize the diff.

clang-format-diff example:

git diff -U0 --no-color HEAD^ | clang-format-diff.py -p1 -i
svn diff --diff-cmd=diff -x-U0 | clang-format-diff.py -i

[ambv]

Black is unable to format line ranges. This would be rather problematic given how it's currently implemented. More importantly, this goes against PEP 8's philosophy of staying consistent within a file (and more generally, within a project). See #134 for a longer explanation.

[Lukas0907]

You can format the whole file and only commit relevant changes via git add -p and revert what you don't want to change.

[ambv]

This is not a planned feature.

[wbolster]

fyi, i wrote https://github.com/wbolster/black-macchiato

[akaihola]

Also FYI, I wrote darker which can apply Black formatting only to lines which have changed in the Git working tree since the last commit.

[sieu-n]

For quick solution, run the following script.

#!/bin/bash

# Get a list of changed Python files in the diff
changed_files=$(git diff --name-only --diff-filter=d HEAD | grep '\.py$')

# Apply isort and black to the changed files
for file in $changed_files; do
  isort "$file"
  black "$file"
done