feat: the main branch doesn't need to be set to work now, and updated docs for getting it to pull down the baseline from the pipeline

Author: isabel-anastasiadis-boost

README.md

@@ -10,13 +10,13 @@ NOTE: similar code will only work correctly if you run a diff on all the files i
 ## Installation
 
 1. Install the codeclimate cli:
-      ``` 
+      ```bash
       brew tap codeclimate/formulae
       brew install codeclimate
       ```
 
 2. Add a `.codeclimate.yml` config file eg:
-      ```
+      ```yml
       ---
       version: "2"
       plugins:
@@ -52,7 +52,7 @@ NOTE: similar code will only work correctly if you run a diff on all the files i
 3. Add a `.reek.yml` config file eg:
 
       See https://github.com/troessner/reek#working-with-rails 
-      ```
+      ```yml
       detectors:
         IrresponsibleModule:
           enabled: false
@@ -90,18 +90,10 @@ NOTE: similar code will only work correctly if you run a diff on all the files i
 
 4. Add a `.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: '85'
-        host: https://gitlab.digitalnz.org/
-        baseline_filename: 'gl-code-quality-report.json'
+      main_branch_name: main # defaults to main
       ```
 
-
-4. Install the gem
+5. Install the gem
 
     Add this line to your application's Gemfile:
 
@@ -113,17 +105,14 @@ NOTE: similar code will only work correctly if you run a diff on all the files i
 
     ```bash
     $ bundle install
-
-    # OR just install it locally
-    $ gem install codeclimate_diff
     ```
 
     Then generate the executable:
 
         $ bundle binstubs codeclimate_diff
 
 
-4. Run the baseline and commit the result to the repo
+6. Run the baseline and commit the result to the repo
 
     ```
     ./bin/codeclimate_diff --baseline
@@ -137,7 +126,7 @@ NOTE: similar code will only work correctly if you run a diff on all the files i
 
 3. Check if you've added any issues (about 10 secs per code file changed on your branch):
 
-    ```
+    ```bash
     # runs on all code files changed in your branch
     ./bin/codeclimate_diff
 
@@ -151,7 +140,43 @@ NOTE: similar code will only work correctly if you run a diff on all the files i
     # only shows the new and fixed issues
     ./bin/codeclimate_diff --new-only
     ```
-4. Now you have time to fix the issues yay!
+
+4. Now you have time to fix the issues, horray!
+
+
+## Setting it up to download the latest baseline from your CI Pipeline (Gitlab only)
+
+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:
+
+      ```yml
+      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:
+      ```yml
+      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 refresh the baseline first!
 
 ## Development
 

lib/codeclimate_diff/downloader.rb

@@ -9,7 +9,7 @@ def self.refresh_baseline_if_configured
       return unless CodeclimateDiff.configuration["gitlab"]["download_baseline_from_pipeline"]
 
       puts "Downloading baseline file from gitlab"
-      branch_name = CodeclimateDiff.configuration["main_branch_name"]
+      branch_name = CodeclimateDiff.configuration["main_branch_name"] || "main"
       project_id = CodeclimateDiff.configuration["gitlab"]["project_id"]
       host = CodeclimateDiff.configuration["gitlab"]["host"]
       baseline_filename = CodeclimateDiff.configuration["gitlab"]["baseline_filename"]

lib/codeclimate_diff/runner.rb

@@ -11,7 +11,7 @@ module CodeclimateDiff
   class Runner
     def self.calculate_changed_filenames(pattern)
       extra_grep_filter = pattern ? " | grep '#{pattern}'" : ""
-      branch_name = CodeclimateDiff.configuration["main_branch_name"]
+      branch_name = CodeclimateDiff.configuration["main_branch_name"] || "main"
       files_changed_str = `git diff --name-only #{branch_name} | grep --invert-match spec/ | grep --extended-regexp '.js$|.rb$'#{extra_grep_filter}`
       puts "Files changed on branch: #{files_changed_str}"