black-codeclimate

Convert the output of black --diff to a report conforming to the Code Climate spec. It is made to be used in GitLab CI to generate a Code Quality report, which will show a nice widget in merge requests listing the file and the lines affected by the reformatting.

black-codeclimate uses unidiff to parse a diff file and detect changes, and outputs a JSON array of Code Climate issue objects reporting the filename and line range of the change. In theory it could be used on any unified diff data, but I only tested it with black --diff's output. Hit me up in the issues if you use it for anything else :)

Usage

Pipe the output of black --diff into black-codeclimate:

black --diff src/ | black-codeclimate > black_report.json

Or specify a file to use as input:

black-codeclimate black.diff > black_report.json

You can also change the severity, description and check_name of the issues in the resulting report by specifying command line flags:

black-codeclimate --severity blocker --description "would reformat [black]" --check-name "black" black.diff > black_report.json

Run black-codeclimate -h to see a list of the available flags.

Adding it to GitLab

Add this step to your .gitlab-ci.yml file:

lint:black:
  stage: lint
  before_script:
    - # Install black and black-codeclimate...
  script:
    # --check fails the job if any inconsistent formatting is detected.
    - black --diff --check src/ > black.diff
  after_script:
    - black-codeclimate black.diff > black_report.json
  artifacts:
    reports:
      codequality: black_report.json
    when: always

This will upload the black_report.json as a GitLab Code Quality artifact. The lines that would be reformatted by black will show up as a merge request widget.