Define 'new' method on model classes

[connorshea]

Describe the bug:
ActiveRecord overrides the new method for all Model classes, e.g. User.new.

It's defined like this in activerecord.rbi:

module ActiveRecord::Inheritance::ClassMethods
  def new(attributes = nil, &block); end
end

And then User, or any other model, inherits that method.

Expected behavior:

I could have an app/controllers/users_controller.rb file like this:

class UsersController < ApplicationController
  def create
    @user = User.new({ username: 'connor' }) # @user is T.untyped because `new` is overridden.
    respond_to do |format|
      if @user.save
        format.html { redirect_to @user, success: "#{@user.username} was successfully created." }
    end
  end
end

The method should be generated as part of Sorbet Rails so its return type can be dynamically set:

class User
  sig { params(args: T.untyped, block: T.untyped).returns(User) }
  def self.new(*args, &block); end
end

Unfortunately it can't just be self_type because that doesn't return an instance of the caller :/

[connorshea]

Actually, since we know what parameters it takes can we use the correct method signature?

class User
  sig { params(attributes: T.untyped, block: T.untyped).returns(User) }
  def self.new(attributes = nil, &block); end
end

[connorshea]

@manhhung741 IIRC, you mentioned at once point that the Sorbet team didn't want to add a special type that'd return an instance of a class (e.g. instead of T.self_type it'd be T.instance_of_self_type), did they say why?

[hdoan741]

That reminds me... Does `Model.create` work? Do we also need one for it?

…

On Sat, Sep 14, 2019 at 6:06 PM Connor Shea ***@***.***> wrote: Actually, since we know what parameters it takes can we use the correct method signature? class User sig { params(attributes: T.untyped, block: T.untyped).returns(User) } def self.new(attributes = nil, &block); endend — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#174?email_source=notifications&email_token=AAFH4AKWNEEI4GND2QTL53DQJWDDFA5CNFSM4IWYW4PKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD6XHAKA#issuecomment-531525672>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAFH4AOLTATAQDXQZOXRFQLQJWDDFANCNFSM4IWYW4PA> .

[connorshea]

create is handled in sorbet-typed right now, but it just returns T.untyped.

[hdoan741]

They want to add it, but they are still working on it. It’s also one of their most requested features currently.

…

On Sat, Sep 14, 2019 at 6:12 PM Connor Shea ***@***.***> wrote: create is handled in sorbet-typed right now, but it just returns T.untyped . — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#174?email_source=notifications&email_token=AAFH4ALXV5H5BNQKJDM5OT3QJWDWDA5CNFSM4IWYW4PKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD6XHBWI#issuecomment-531525849>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAFH4APRF7SUHLH5DLJSR6TQJWDWDANCNFSM4IWYW4PA> .

[connorshea]

Where should I put the create_method for this? 🤔