Setup Rubocop

[304]

As suggested in #1531

I would like to introduce rubocop to the project that should help to maintain a consistent code style.
The set of changes is quite big and it will take several PRs to finalize it.

The following PR:

• adds rubocop gem
• creates .rubocop.yml (for configurations)
• makes changes as rubocop suggests (mostly by using --safe-auto-correct option)
• disables multiple cops (it would be a gigantic PR if all of them are enabled at once)
• adjusts Rakefile to perform rubocop checks by default

It enables Travis CI checks for the code style violations and that should already bring some value.
Next steps would be to re-enable cops from .rubocop.yml file until the check will pass without any warnings.

[namusyaka]

To merge this, we need to carefully review the changes. I'd like sinatra helpers to review these changes.
/cc @jkowens @olleolleolle @mwpastore

[olleolleolle]

@304 - Stellar work. Thank you so much for this! So many improvements to readability.

I have read the PR commit-by-commit, and its shows that you put in some thought into which change should come before the other. It was easy to follow along – each step was separate and followed from the earlier step. A story, if you will. Thanks for that, as well.

Solve the conflict, and then we can merge this, I think.

---

As for future work on RuboCop:

RuboCop has a concept of a TODO file - a list of remaining issues to be skipped. Having such a file would allow us to keep enabled the rules we want to follow for new code, while at the same time allowing the old code not to trouble that effort.

If some of the rules which didn't pass right now are desirable to pass in the future, we could use rubocop --auto-gen-config to create and include a file .rubocop_todo.yml, oh, I blogged about this workflow.

[olleolleolle]

Please solve the Git conflict, so that we can go forward with this great improvement. Thank you!

[304]

@olleolleolle Thank you for the review! 🎉
I've rebased the branch against master and it has no conflicts anymore.

I was not aware that Rubocop has a concept of a TODO file. It seems to be a really nice way how to proceed with future fixes. Thank you for sharing that!

[olleolleolle]

@304 👋 Hi!!!!

Would you mind rebasing again?

The note about required Ruby version 2.3+ is also relevant.

[epergo]

Hello folks, could we push this? 🙏

If needed, I could continue with it

[namusyaka]

I'm thinking this can be merged into v2.1.1.

[jkowens]

Rubocop was reporting a ShadowedException. It seems SystemCallError would also rescue Errno::ECONNREFUSED, Errno::ECONNRESET errors.

[olleolleolle]

Thanks, everyone, ❤️ ! This was a barn-raising, many hands needed.

[mvz]

This seems to have resulted in an accidental breaking change for direct users of rack-protection: omniauth/omniauth#1089