From 949f3987ad337fb23d411310d39b5c43bee854e5 Mon Sep 17 00:00:00 2001
From: stopdropandrew <andrew@andrew.local>
Date: Wed, 5 Nov 2008 13:49:17 -0800
Subject: [PATCH] Count calculations respect explicit selects specified in scopes.

---
 activerecord/lib/active_record/calculations.rb |   20 ++++++++++++++------
 activerecord/test/cases/calculations_test.rb   |   13 ++++++++++++-
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb
index 5e33cf1..18b2bf1 100644
--- a/activerecord/lib/active_record/calculations.rb
+++ b/activerecord/lib/active_record/calculations.rb
@@ -132,23 +132,31 @@ module ActiveRecord
       protected
         def construct_count_options_from_args(*args)
           options     = {}
-          column_name = :all
-          
+          column_name = nil
+        
           # We need to handle
           #   count()
           #   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]
           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]
+              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
-          
-          [column_name, options]
+          end
+        
+          [column_name || :all, options]
         end
 
         def construct_calculation_sql(operation, column_name, options) #:nodoc:
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 0fa6150..d2740c1 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -251,7 +251,18 @@ class CalculationsTest < ActiveRecord::TestCase
     assert_equal 6, Account.count(:distinct => true, :include => :firm)
     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
-- 
1.5.5