allow ActiveRecord::Core#slice to use array arg #26838

merged 1 commit into from Oct 31, 2016


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This allows ActiveRecord::Core#slice to take an array of attributes to retain in addition to a splat of arguments, making it behave like like ActiveRecord::QueryMethods#select.

Other Information

Imagine you have some code as follows:

class User < ApplicationRecord
  PUBLIC_FIELDS = %i(foo bar baz).freeze

  scope :public_fooed, -> { select(PUBLIC_FIELDS).where(foo: true) }

  def publicize

It annoys me that to filter attributes at the model class level (while doing a ::select), you don't need to splat PUBLIC_FIELDS, but you do when doing it at the model object level (with #slice).

Since ActiveRecord::Core#slice will never have attributes (or methods) that are arrays, we can safely flatten its arguments to make it behave like ::select with regard to array arguments.

@schneems schneems was assigned by rails-bot Oct 20, 2016

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Could you add a test case?


@rafaelfranca sure thing, let me know if 9f9b999 will suffice


Only a small comment. After you fix it could you add a CHANGELOG entry and squash your commits? Thanks.

+ content: "accept arrays so I don't have to splat"
+ }.with_indifferent_access
+ topic =
+ assert_equal topic.slice(attrs.keys), attrs
rafaelfranca Oct 22, 2016 Member

it is the other way around. assert_equal attrs, topic.slice(attrs.keys)


@rafaelfranca done and done


Checking in on this PR.

@@ -1,3 +1,7 @@
+* Allow `slice` to take an array of methods (without need for splatting)
prathamesh-sonpatki Oct 31, 2016 Member

Can you add a fullstop at the end.

Cohen Carlisle allow ActiveRecord::Core#slice to use array arg

@prathamesh-sonpatki Done and rebased/squashed.


Looks good, let's wait for the committer now 😄

@guilleiguaran guilleiguaran merged commit 3c9eb70 into rails:master Oct 31, 2016

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guilleiguaran commented Oct 31, 2016 edited

thank you very much for this, I've missed having this in some occasions

@Cohen-Carlisle Cohen-Carlisle deleted the Cohen-Carlisle:activerecord-slice-array-args branch Oct 31, 2016
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