CodeclimateDiff

This tool lets you see how changes in your branch will affect the code quality (what issues you've added, fixed, and what issues are outstanding in the files you've touched that could be fixed while you're in the area.)

It runs the https://hub.docker.com/r/codeclimate/codeclimate docker image under the hood, which pays attention to all the normal Code Climate configurations.

1. Make sure docker is installed and running

2. Add a .codeclimate.yml config file eg:

   ---
   version: "2"
   plugins:
     rubocop:
       enabled: true
       channel: rubocop-1-36-0
     reek:
       enabled: true
   
   exclude_patterns:
     - config/
     - db/
     - dist/
     - features/
     - public/
     - "**/node_modules/"
     - script/
     - "**/spec/"
     - "**/test/"
     - "**/tests/"
     - Tests/
     - "**/vendor/"
     - "**/*_test.go"
     - "**/*.d.ts"
     - "**/*.min.js"
     - "**/*.min.css"
     - "**/__tests__/"
     - "**/__mocks__/"
     - "/.gitlab/"
     - coverage/ . # simple cov

3. Add a .reek.yml config file eg:

   See https://github.com/troessner/reek#working-with-rails

   detectors:
     IrresponsibleModule:
       enabled: false
   
     NilCheck:
       enabled: false
   
     ManualDispatch:
       enabled: false
   
     LongParameterList:
       max_params: 4  # defaults to 3.  You want this number realistic but stretchy so we can move it down
   
     TooManyStatements:
       max_statements: 10  # defaults to 5.  You want this number realistic but stretchy so we can move it down
   
     UtilityFunction:
       public_methods_only: true
   
     UncommunicativeVariableName:
       accept:
         - e
   
   directories:
     "app/controllers":
       IrresponsibleModule:
         enabled: false
       NestedIterators:
         max_allowed_nesting: 2
       UnusedPrivateMethod:
         enabled: false
       InstanceVariableAssumption:
         enabled: false
     "app/helpers":
       IrresponsibleModule:
         enabled: false
       UtilityFunction:
         enabled: false
       FeatureEnvy:
         enabled: false
     "app/mailers":
       InstanceVariableAssumption:
         enabled: false
     "app/models":
       InstanceVariableAssumption:
         enabled: false

4. Add a .codeclimate_diff.yml configuration file

   main_branch_name: master # defaults to main
   threshold_to_run_on_all_files: 8  # when you reach a certain number of files changed, it becomes faster to analyze all files rather than analyze them one by one.
   

5. Install the gem

   Add this line to your application's Gemfile:

   gem 'codeclimate_diff', github: 'boost/codeclimate_diff'

   Install the gem:

   $ bundle install

   Then generate the executable:

    $ bundle binstubs codeclimate_diff
   

   Add codeclimate_diff_baseline.json to .gitignore

1. Create a feature branch for your work

2. Do some work

3. Check if you've added any issues (about 10 secs per code file changed on your branch):

   # runs on each file changed in your branch (about 10 secs per code file changed on your branch)
   ./bin/codeclimate_diff
   # baseline is now generated on first run, to generate new baseline, delete the existing.
   OR
   
   # filters the changed files in your branch futher by a grep pattern
   ./bin/codeclimate_diff --pattern places
   
   OR
   
   # only shows the new and fixed issues
   ./bin/codeclimate_diff --new-only
   
   OR
   
   # always analyzes all files rather than the changed files one by one, even if below the 'threshold_to_run_on_all_files' setting.
   # NOTE: similar code issues will only work 100% correctly if you use this setting (otherwise it might miss a similarity with a file you didn't change and think you fixed it)
   ./bin/codeclimate_diff --all

4. Now you have time to fix the issues, horray!

Gitlab has a codeclimate template you can add to your pipeline that runs on main builds and then runs on your branch and outputs a difference (see https://docs.gitlab.com/ee/ci/testing/code_quality.html).

With a few tweaks to your CI configuration, we can pull down the main build baseline from the job so we don't have to do it locally.

1. In your Gitlab CI Configuration where you include the Code-Quality.gitlab-ci.yml template:

   include:
     - template: Code-Quality.gitlab-ci.yml
   
   # add this bit:
   code_quality:
     artifacts:
       paths: [gl-code-quality-report.json] .  # without this, the artifact can't be downloaded

2. Add your project settings to the .codecimate_diff.yml configuration file:

   main_branch_name: main
   
   # settings to pull down the baseline from the pipeline in Gitlab before checking your branch
   gitlab:
     download_baseline_from_pipeline: true   # If false or excluded, you will need to generate the baseline manually
     project_id: '<project id>'
     host: https://gitlab.digitalnz.org/
     baseline_filename: 'gl-code-quality-report.json'

3. Create a personal access token with read_api access and save it in the CODECLIMATE_DIFF_GITLAB_PERSONAL_ACCESS_TOKEN env variable

Now when you run it on the changed files in your branch, it will download the latest baseline first!

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/codeclimate_diff.