Add Style/RequireOrder cop

[r7kamura]

Many projects have require and require_relative in alphabetical order by convention, the rubocop gem itself being one example. I thought it would be good to have a cop to provide such consistency.

As a good example, rubocop-rspec inspects this with tests. Such checks are replaced by this cop.

• https://github.com/rubocop/rubocop-rspec/blob/v2.15.0/spec/project/project_requires_spec.rb

Like Bundler/OrderedGems, code separated by a blank line is considered a different group, so if there are obvious dependencies but you really don't want to write require_relative in each file, it is better to separate the groups. lib/rubocop/formatter.rb is a good example of that.

• https://github.com/rubocop/rubocop/blob/v1.39.0/lib/rubocop/formatter.rb#L9-L27

Unfortunately, the dependencies written in lib/rubocop.rb are too complex, so I gave up on organizing this at the time of introducing this cop and decided to ignore it from this cop. Personally, if one file A depends on another file B, I prefer to indicate that fact by writing require_relative in file A, but I don't think that is the practice in the rubocop gem, so I don't want to go into this issue here.

Since this cop enforces the rule "always sort them in alphabetical order within a group", I don't think false-positive will occur, but applying autocorrection obviously changes the behavior from the original code, so I have set SafeAutoCorrect: false.

Ideally, I believe it is a good manner that the code to always be written in such a way that it does not depend on the order of require, but I set Enabled: false because this cop has a large impact and may or may not be acceptable depending on the preference of the project. I think this cop is rather opinionated, so I would be glad to get your opinion on the policy.

---

Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.

[bbatsov]

I love this suggestion and the thoughtful analysis you've submitted alongside it! I'm only wondering if this cop should also suggest to keep require and require_relative sections ordered as well (e.g. require first, require_relative afterwards or vice-versa).

[bbatsov]

You might mention here that a blank line introduces a new section or something like this.

[r7kamura]

'm only wondering if this cop should also suggest to keep require and require_relative sections ordered as well (e.g. require first, require_relative afterwards or vice-versa).

I guess it would be difficult to enforce that, since there would be case where you want to write relative_require before require, or vice versa, depending on the situation. If we want to do that, it might be better to prepare something like Style/RequireSectionOrder separately.

[zhuravel]

@r7kamura @bbatsov This cop fails for code like:

def load_account
  @account = Account.find(params.require(:account_id))
end

Trace:

An error occurred while Style/RequireOrder cop was inspecting /Users/bohdan/Projects/talkable/app/controllers/account/accesses_controller.rb:69:28.
undefined method `send_type?' for :account_id:Symbol

            break unless sibling.send_type?
                                ^^^^^^^^^^^
/Users/bohdan/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/rubocop-1.40.0/lib/rubocop/cop/style/require_order.rb:66:in `block in find_previous_older_sibling'

[koic]

@zhuravel Thank you for the feedback. That issue will be resolved by #11254.