Idea for new Aliases cops

[noraj]

I would like to suggest an idea 💡 : having more aliases style cops!

There are many aliases in Ruby

• Hash#select ↔️ Hash#filter
• Hash#each_pair ↔️ Hash#each
• Hash#include? ↔️ Hash#has_key?
• Hash#value? ↔️ Hash#has_value?
• Array#push ↔️ Array#append
• Array#collect ↔️ Array#map
• Array#find_index ↔️ Array#index
• etc. just to name a few

I looked for existing alias cops, and it seems there are no alias cops for Ruby and 2 alias cops for RoR Rails/ActiveRecordAliases and Rails/ActiveSupportAliases.

Note: Style/Alias is for enforcing the use of either #alias or #alias_method not to enforce the style of aliases usage.

It would be nice to have one or several aliases style cops for the ones who want to implement a consistent naming convention.

But then, a new question arises: are we going to make a group cop with all aliases (maybe too large), one cop per group / class / module (how to split that?) or one cop per alias (probably not, that would be too much)?

• Option 1: Style/Aliases for all Ruby standard library aliases (same with RSpec/Aliases, Minitest/Aliases)
• Option 2: Style/ArrayAliases, Style/HashAliases, etc. aliases grouped by class / module
• Option 3: Style/ArrayPushAlias, Style/ArrayCollectAlias, etc. one cop per alias

Then I see one parameter so that it would be configurable:

EnforceAliases:

• never (default): using aliases is forbidden, must use only original method name
• always: using original method name is forbidden, must use only aliases
• mixed: allow using both aliases and original method names

The depending on the grouping chosen:

• if Option 1 then having an AllowedClasses parameter to disable the cop for a specific class AllowedClasses: [Hash].
• if Option 2 then having an AllowedMethods parameter to disable the cop for a specific method AllowedMethods: [push, collect].
• if Option 3 then I see no additional parameter needed

[Earlopain]

RuboCop will have trouble with types here I think, bunch of false positives. It's lacking the type information for this to properly work.

I guess it may make sense to have a generic cop that checks for methodA -> methodB but enforcing one over the other by default seems bad. I would rather have it 100% configured by the user with no defaults at all. Basically:

Style/AliasedMethods:
  Enabled: true
  Aliases:
    find_index: index
    each_pair: pair
    etc...

[noraj]

Yeah, why not no default.

[dvandersluis]

I don't think any new cop is needed here.

You can add your own methods to Style/CollectionMethods, and some of these are already covered.

Style/CollectionMethods:
  PreferredMethods:
    filter: 'select'

The Hash methods (#has_key? vs key? and #has_value? vs value?) are covered by Style/PreferredHashMethods

See https://docs.rubocop.org/rubocop/cops_style.html#stylecollectionmethods and https://docs.rubocop.org/rubocop/cops_style.html#stylepreferredhashmethods