Merge pull request #14711 from swoker/activerecord_fix_aggregate_methods_with_select

Activerecord fix aggregate methods with select

activerecord/CHANGELOG.md

@@ -289,4 +289,11 @@
 
     *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.

activerecord/lib/active_record/association_relation.rb

@@ -9,6 +9,14 @@ module ActiveRecord
       @association
     end
     
+    def size
+      @association.size
+    end
+
+    def empty?
+      @association.empty?
+    end
+        
     private
 
     def exec_queries

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(:all)
-        c = count
         c.respond_to?(:zero?) ? c.zero? : c.empty?
       end
     end

activerecord/test/cases/associations/eager_test.rb

@@ -1198,6 +1198,14 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal authors(:bob), author
   end
   
+  test "preloading with a polymorphic association and using the existential predicate but also using a select" do
+    assert_equal authors(:david), authors(:david).essays.includes(:writer).first.writer
+
+    assert_nothing_raised do
+      authors(:david).essays.includes(:writer).select(:name).any?
+    end
+  end
+  
   test "preloading with a polymorphic association and using the existential predicate" do
     assert_equal authors(:david), authors(:david).essays.includes(:writer).first.writer
 

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)