Fix error for aggregate methods with select, see issue #13648

3 files changed, 19 insertions, 3 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index d39e808f5b..a23981a22b 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -264,4 +264,11 @@
 
     *Yves Senn*
 
+*	Fixed error for aggregate methods (empty?, any?, count) with select() 
+	which created invalid SQL
+	
+	Fixes #13648
+	
+	*Simon Woker*
+	
 Please check [4-1-stable](https://github.com/rails/rails/blob/4-1-stable/activerecord/CHANGELOG.md) for previous changes.
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 4d37ac6e2b..7cdae176a1 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -238,7 +238,7 @@ module ActiveRecord
 
     # Returns size of the records.
     def size
-      loaded? ? @records.length : count
+      loaded? ? @records.length : count(:all)
     end
 
     # Returns true if there are no records.
@@ -248,8 +248,7 @@ module ActiveRecord
       if limit_value == 0
         true
       else
-        # FIXME: This count is not compatible with #select('authors.*') or other select narrows
-        c = count
+        c = count(:all)
         c.respond_to?(:zero?) ? c.zero? : c.empty?
       end
     end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 2aa6d643a5..da932b7663 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -824,6 +824,16 @@ class RelationTest < ActiveRecord::TestCase
     assert_raises(ActiveRecord::ActiveRecordError) { Author.limit(10).delete_all }
   end
 
+  def test_select_with_aggregates
+    posts = Post.select(:title, :body)
+    
+    assert_equal 11, posts.count(:all)
+    assert_equal 11, posts.size
+    assert posts.any?
+    assert posts.many?
+    assert ! posts.empty?    
+  end
+  
   def test_select_takes_a_variable_list_of_args
     david = developers(:david)