Enable Style/ReturnNil cop

[larouxn]

Proposing we enable Style/ReturnNil to enforce return if/unless condition style over return nil unless condition as the nil component is redundant/unnecessary. Let's make this consistent.

https://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Style/ReturnNil

[sambostock]

I'm not necessarily opposed to this, but some people might prefer the explicitness. 🤷 I do think consistency would be nice though, and I can't see us enabling the opposite style (i.e. enforcing return nil).

Can you run Rubocop against Core with this setting and see how many offenses there are?

[larouxn]

I'm not necessarily opposed to this, but some people might prefer the explicitness. 🤷 I do think consistency would be nice though, and I can't see us enabling the opposite style (i.e. enforcing return nil).

Yeah I'm sure some peep would prefer explicit nil returns but I think in general simply returning based on a condition (implied nil) is equally valid and if we are to choose one or the other for consistency I think return condition is better than return nil condition.

Can you run Rubocop against Core with this setting and see how many offenses there are?

Cannot seem to swap the rubocop-shopify gem nor add the rule to rubocop.yml as I'm having network congestion issues given its core and I'm on train grade WiFi. That said, I was able to simply query for all return nil and there are 1917 offenses.

[rafaelfranca]

I'm being more conservative on enabling cops that can have impact on existing code and doesn't add much value other than consistency, but I'm ok with this cop being enabled.

[larouxn]

👋 @sambostock, I was finally able to run this cop against core. 1594 infractions. Results here.