Fix regression caused due to removal of select method from CollectionAssociation

- CollectionAssociation#select was removed in
  https://github.com/rails/rails/pull/25989 in favor of
  QueryMethods#select but it caused a regression when passing arguments
  to select and a block.
- This used to work earlier in Rails 4.2 and Rails 5. See gist
  https://gist.github.com/prathamesh-sonpatki/a7df922273473a77dfbc742a4be4b618.
- This commit restores the behavior of Rails 4.2 and Rails 5.0.0 to
  allow passing arguments and block at the same time but also deprecates
  it.
- Because, these arguments do not have any effect on the output of
  select when select is used with a block.
- Updated documentation to remove the example passing arguments and
  block at the same time to `CollectionProxy#select`.

4 files changed, 22 insertions, 7 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index f847c71420..cc7ba49c87 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Deprecate passing arguments and block at the same time to
+    `ActiveRecord::QueryMethods#select`.
+
+    *Prathamesh Sonpatki*
+
 *   Optimistic locking: Added ability update locking_column value.
     Ignore optimistic locking if update with new locking_column value.
 
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index dda240585e..0800639c24 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -106,12 +106,6 @@ module ActiveRecord
       #   #      #<Pet id: 2, name: "Spook", person_id: 1>,
       #   #      #<Pet id: 3, name: "Choo-Choo", person_id: 1>
       #   #    ]
-      #
-      #   person.pets.select(:name) { |pet| pet.name =~ /oo/ }
-      #   # => [
-      #   #      #<Pet id: 2, name: "Spook">,
-      #   #      #<Pet id: 3, name: "Choo-Choo">
-      #   #    ]
 
       # Finds an object in the collection responding to the +id+. Uses the same
       # rules as ActiveRecord::Base.find. Returns ActiveRecord::RecordNotFound
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 9fbbe32e7f..c6d0902e0d 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -242,7 +242,16 @@ module ActiveRecord
     #   Model.select(:field).first.other_field
     #   # => ActiveModel::MissingAttributeError: missing attribute: other_field
     def select(*fields)
-      return super if block_given?
+      if block_given?
+        if fields.any?
+          ActiveSupport::Deprecation.warn(<<-WARNING.squish)
+            When select is called with a block, it ignores other arguments. This behavior is now deprecated and will result in an ArgumentError in Rails 5.1. You can safely remove the arguments to resolve the deprecation warning because they do not have any effect on the output of the call to the select method with a block.
+          WARNING
+        end
+
+        return super()
+      end
+
       raise ArgumentError, "Call this with at least one field" if fields.empty?
       spawn._select!(*fields)
     end
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index 0ce67f971b..c1e04714fb 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -788,6 +788,13 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal [1], posts(:welcome).comments.select { |c| c.id == 1 }.map(&:id)
   end
 
+  def test_select_with_block_and_specific_attributes
+    assert_deprecated do
+      comments = posts(:welcome).comments.select(:id, :body) { |c| c.id == 1 }
+      assert_equal [1], comments.map(&:id)
+    end
+  end
+
   def test_select_without_foreign_key
     assert_equal companies(:first_firm).accounts.first.credit_limit, companies(:first_firm).accounts.select(:credit_limit).first.credit_limit
   end