Allow use of and/or operators for control flow

[davepilling]

Taken from https://github.com/rubocop/ruby-style-guide

[boardfish]

Does our RuboCop config support this too?

[davepilling]

Does our RuboCop config support this too?

We'll need to update this rule:

Style/AndOr:
  EnforcedStyle: always

to:

Style/AndOr:
  EnforcedStyle: conditionals

[fran-fac]

Would we want to use...

user.suspended? and return :denied

instead of a guard if?

return :denied if user.suspended?

How do we choose? A bit wary of opening up a "two ways to do one thing" situation, when the existing codebase is consistently using a form that looks just as powerful.

The feeling I have is that and/or are more readable when the method call reads like an action:

do_something or return :failure

while guard if/unless work better with boolean methods:

return :invalid unless is_valid?(param)

However, the first case requires the method to return a truth-y value, which feels like... I suppose it reminds me of PHP, where most methods return false|value and and/or are often used for control flow – but there are not guard ifs in PHP!

[davepilling]

I would go with the return...if if that case. I do think think this is a poor example when you could use a guard if instead.

As you say, I think and/or work better when you're checking whether an action was successful. You can achieve the same thing with if/unless but I find that is actually less readable in the action case:

do_something or return :failure

return :failure unless do_something

Happy to modify the examples if you think that pattern makes sense.

[fran-fac]

In our examples above, do_something needs to return a truth-y value, but does not guarantee a boolean as do_something? would.

Are we putting a invisible dependency on the called method then, and risk someone changing do_something in a perfectly valid way, which breaks the implicit truth-y-ness return requirement? Is that an actual risk, and is it acceptable in respect to what we gain from relaxing the rules around and/or?

(Maybe the above is not very clear, I'll try again with a fresh brain tomorrow)