Respect new records for `CollectionProxy#uniq`

Currently if `CollectionProxy` has more than one new record,
`CollectionProxy#uniq` result is incorrect.

And `CollectionProxy#uniq` was aliased to `distinct` in a1bb6c8b06db.
But the `uniq` method and the `SELECT DISTINCT` method are different
methods. The doc in `CollectionProxy` is for the `SELECT DISTINCT`
method, not for the `uniq` method.

Therefore, reverting the alias in `CollectionProxy` to fix the
inconsistency and to have the both methods.

2 files changed, 16 insertions, 10 deletions

diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index f8aac895d7..7cd25ea524 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -246,13 +246,6 @@ module ActiveRecord
         end
       end
 
-      def distinct
-        seen = {}
-        load_target.find_all do |record|
-          seen[record.id] = true unless seen.key?(record.id)
-        end
-      end
-
       # Replace this collection with +other_array+. This will perform a diff
       # and delete/add only records that have changed.
       def replace(other_array)
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 0800639c24..35a98d7090 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -718,6 +718,12 @@ module ActiveRecord
         @association.destroy(*records)
       end
 
+      ##
+      # :method: distinct
+      #
+      # :call-seq:
+      #   distinct(value = true)
+      #
       # Specifies whether the records should be unique or not.
       #
       #   class Person < ActiveRecord::Base
@@ -732,10 +738,17 @@ module ActiveRecord
       #
       #   person.pets.select(:name).distinct
       #   # => [#<Pet name: "Fancy-Fancy">]
-      def distinct
-        @association.distinct
+      #
+      #   person.pets.select(:name).distinct.distinct(false)
+      #   # => [
+      #   #      #<Pet name: "Fancy-Fancy">,
+      #   #      #<Pet name: "Fancy-Fancy">
+      #   #    ]
+
+      #--
+      def uniq
+        load_target.uniq
       end
-      alias uniq distinct
 
       def calculate(operation, column_name)
         null_scope? ? scope.calculate(operation, column_name) : super