Ensure calculations respect scoped :select [#1334 state:resolved]

Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

activerecord/lib/active_record/calculations.rb

@@ -147,16 +147,24 @@ module ActiveRecord
           #   count(:column_name=:all)
           #   count(options={})
           #   count(column_name=:all, options={})
+          #   selects specified by scopes
           case args.size
+          when 0
+            column_name = scope(:find)[:select] if scope(:find)
           when 1
-            args[0].is_a?(Hash) ? options = args[0] : column_name = args[0]
+            if args[0].is_a?(Hash)
+              column_name = scope(:find)[:select] if scope(:find)
+              options = args[0]
+            else
+              column_name = args[0]
+            end
           when 2
             column_name, options = args
           else
             raise ArgumentError, "Unexpected parameters passed to count(): #{args.inspect}"
-          end if args.size > 0
+          end
 
-          [column_name, options]
+          [column_name || :all, options]
         end
 
         def construct_calculation_sql(operation, column_name, options) #:nodoc:

activerecord/test/cases/calculations_test.rb

@@ -264,6 +264,17 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal 4, Account.count(:distinct => true, :include => :firm, :select => :credit_limit)
   end
 
+  def test_should_count_scoped_select
+    Account.update_all("credit_limit = 50")
+    assert_equal 1, Account.scoped(:select => "DISTINCT credit_limit").count
+  end
+
+  def test_should_count_scoped_select_with_options
+    Account.update_all("credit_limit = 50")
+    Account.first.update_attribute('credit_limit', 49)
+    assert_equal 1, Account.scoped(:select => "DISTINCT credit_limit").count(:conditions => [ 'credit_limit >= 50'] )
+  end
+
   def test_should_count_manual_select_with_include
     assert_equal 6, Account.count(:select => "DISTINCT accounts.id", :include => :firm)
   end