Dangerfile

# Adapted from https://github.com/ruby-grape/danger/blob/master/Dangerfile
# Q: What is a Dangerfile, anyway? A: See http://danger.systems/

# ------------------------------------------------------------------------------
# Additional pull request data
# ------------------------------------------------------------------------------
pr_number = github.pr_json["number"]
pr_url = github.pr_json["_links"]["html"]["href"]

# ------------------------------------------------------------------------------
# What changed?
# ------------------------------------------------------------------------------
has_lib_changes = !git.modified_files.grep(/^lib/).empty?
has_test_changes = !git.modified_files.grep(/^(features|spec|test)/).empty?
has_changelog_changes = git.modified_files.include?("CHANGELOG.md")

# ------------------------------------------------------------------------------
# You've made changes to lib, but didn't write any tests?
# ------------------------------------------------------------------------------
if has_lib_changes && !has_test_changes
  if %w(features spec test).any? { |dir| Dir.exist?(dir) }
    warn("There are code changes, but no corresponding tests. "\
         "Please include tests if this PR introduces any modifications in "\
         "behavior.",
         :sticky => false)
  else
    markdown <<-MARKDOWN
Thanks for the PR! This project lacks automated tests, which makes reviewing and approving PRs somewhat difficult. Please make sure that your contribution has not broken backwards compatibility or introduced any risky changes.

MARKDOWN
  end
end

# ------------------------------------------------------------------------------
# Have you updated CHANGELOG.md?
# ------------------------------------------------------------------------------
if !has_changelog_changes && has_lib_changes
  markdown <<-MARKDOWN
Here's an example of a CHANGELOG.md entry (place it immediately under the `* Your contribution here!` line):

```markdown
* [##{pr_number}](#{pr_url}): #{github.pr_title} - [@#{github.pr_author}](https://github.com/#{github.pr_author})
```
MARKDOWN
  warn("Please update CHANGELOG.md with a description of your changes. "\
       "If this PR is not a user-facing change (e.g. just refactoring), "\
       "you can disregard this.", :sticky => false)
end

# ------------------------------------------------------------------------------
# Did you remove the CHANGELOG's "Your contribution here!" line?
# ------------------------------------------------------------------------------
if has_changelog_changes
  unless IO.read("CHANGELOG.md") =~ /^\s*\* Your contribution here/i
    fail(
      "Please put the `* Your contribution here!` line back into CHANGELOG.md.",
      :sticky => false
    )
  end
end