Fixed that count distinct should use the selected column even when using...

Fixed that count distinct should use the selected column even when using :include (closes #5251) [anna@wota.jp]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4417 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Fixed that count distinct should use the selected column even when using :include #5251 [anna@wota.jp]
+
 * Fixed that :includes merged from with_scope won't cause the same association to be loaded more than once if repetition occurs in the clauses #5253 [alex@purefiction.net]
 
 * Allow models to override to_xml.  #4989 [Blair Zajac <blair@orcaware.com>]

activerecord/lib/active_record/calculations.rb

@@ -155,7 +155,7 @@ def construct_calculation_sql(operation, column_name, options) #:nodoc:
 
           if merged_includes.any? && operation.to_s.downcase == 'count'
             options[:distinct] = true
-            column_name = [table_name, primary_key] * '.'
+            column_name = options[:select] || [table_name, primary_key] * '.'
           end
 
           sql  = "SELECT #{operation}(#{'DISTINCT ' if options[:distinct]}#{column_name}) AS #{aggregate_alias}"

activerecord/test/calculations_test.rb

@@ -187,4 +187,9 @@ def test_should_reject_invalid_options
     assert_raises(ArgumentError) { Company.send(:validate_calculation_options, :sum,   :foo => :bar) }
     assert_raises(ArgumentError) { Company.send(:validate_calculation_options, :count, :foo => :bar) }
   end
+
+  def test_should_count_selected_field_with_include
+    assert_equal 5, Account.count(:distinct => true, :include => :firm)
+    assert_equal 3, Account.count(:distinct => true, :include => :firm, :select => :credit_limit)
+  end
 end