Make CircleCI post diff review for style violation

The CircleCI robot now also posts a review comment
directly on the diff (on GitHub, the changes tab),
where the style violations take place.

scripts/report_errors.sh

@@ -44,6 +44,28 @@ function post_error_to_github
       --header 'content-type: application/json' \
       -u stackenbotten:$GITHUB_ACCESS_TOKEN \
       --data "{\"body\": \"There was an error when running \`$CIRCLE_JOB\` for commit \`$CIRCLE_SHA1\`:\n\`\`\`\n$FORMATTED_ERROR_MSG\n\`\`\`\nPlease check that your changes are working as intended.\"}"
+
+    post_review_comment_to_github
+}
+
+function post_review_comment_to_github
+{
+    GITHUB_API_URL="https://api.github.com/repos/$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME/pulls/$CIRCLE_PR_NUMBER/comments"
+
+    sed -i 1d $ERROR_LOG
+
+    while read line
+    do
+        ERROR_PATH=$(echo $line | grep -oE ".*\.cpp")
+        ERROR_LINE=$(echo $line | grep -oE "[0-9]*")
+
+        curl --request POST \
+          --url $GITHUB_API_URL \
+          --header 'accept: application/vnd.github.v3+json, application/vnd.github.comfort-fade-preview+json' \
+          --header 'content-type: application/json' \
+          -u stackenbotten:$GITHUB_ACCESS_TOKEN \
+          --data "{\"commit_id\": \"$CIRCLE_SHA1\", \"path\": \"$ERROR_PATH\", \"line\": $ERROR_LINE, \"side\": \"LEFT\", \"body\": \"Coding style error\"}"
+    done < $ERROR_LOG
 }
 
 trap report_error_to_github EXIT