Add annotation for ActiveRecord::Relation#each

[marknuzz]

Closes Shopify/tapioca#2034

The generic type_member was necessary to prevent the following error:

type_member type Enumerable::Elem used outside of the class definition https://srb.help/5072

Using anything other than { { fixed: T.untyped } } would cause breakages that would need to be addressed separately.

For example: Using { { upper: ActiveRecord::Base } } doesn't work as the rails :has_and_belongs_to_many leads to Tapioca rbi output that don't inherit from anything, even though the classes should inherit from ActiveRecord::Base. Additionally, there may be user code that references ActiveRecord::Relation, which would break unless it was changed to something like ActiveRecord::Relation[ActiveRecord::Base] (and the class would need to be patched to extend T::Generic, which seems unacceptable).

Type of Change

• Add RBI for a new gem
• Modify RBI for an existing gem
• Other:

Changes

• Gem name: activerecord
• Gem version: 7.1.3.4
• Tapioca version: 0.16.2
• Sorbet version: 0.5.11602

[marknuzz]

I have signed the CLA!

[amomchilov]

Let me just check something internally, and I'll merge shortly.

[amomchilov]

Hmmm, it's odd that Sorbet is requiring this, as ActiveRecord::Relation already does an include Enumerable:

https://github.com/rails/rails/blob/f481602bc5f0e2b79f95b73d7cc343303dd69672/activerecord/lib/active_record/relation.rb#L67

[amomchilov]

NVM, Sorbet always makes you re-declare generic type variables.