rename `Relation#uniq` to `Relation#distinct`. `#uniq` still works.

The similarity of `Relation#uniq` to `Array#uniq` is confusing. Since our
Relation API is close to SQL terms I renamed `#uniq` to `#distinct`.

There is no deprecation. `#uniq` and `#uniq!` are aliases and will continue
to work. I also updated the documentation to promote the use of `#distinct`.

1 files changed, 5 insertions, 1 deletions

diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 26cbb03892..3de2c6ab58 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -492,6 +492,7 @@ class RelationTest < ActiveRecord::TestCase
     expected_taggings = taggings(:welcome_general, :thinking_general)
 
     assert_no_queries do
+      assert_equal expected_taggings, author.taggings.distinct.sort_by { |t| t.id }
       assert_equal expected_taggings, author.taggings.uniq.sort_by { |t| t.id }
     end
 
@@ -1269,7 +1270,7 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal posts(:welcome),  comments(:greetings).post
   end
 
-  def test_uniq
+  def test_distinct
     tag1 = Tag.create(:name => 'Foo')
     tag2 = Tag.create(:name => 'Foo')
 
@@ -1277,11 +1278,14 @@ class RelationTest < ActiveRecord::TestCase
 
     assert_equal ['Foo', 'Foo'], query.map(&:name)
     assert_sql(/DISTINCT/) do
+      assert_equal ['Foo'], query.distinct.map(&:name)
       assert_equal ['Foo'], query.uniq.map(&:name)
     end
     assert_sql(/DISTINCT/) do
+      assert_equal ['Foo'], query.distinct(true).map(&:name)
       assert_equal ['Foo'], query.uniq(true).map(&:name)
     end
+    assert_equal ['Foo', 'Foo'], query.distinct(true).distinct(false).map(&:name)
     assert_equal ['Foo', 'Foo'], query.uniq(true).uniq(false).map(&:name)
   end