From d52ee204bfeae5e95a6fb086643fe513bd5da07f Mon Sep 17 00:00:00 2001
From: Nik Wakelin <nik@codetocustomer.com>
Date: Mon, 23 Jun 2008 10:14:33 +1200
Subject: [PATCH]  Added syntactic sugar to belongs_to associations in ActiveRecord hash conditions

---
 activerecord/lib/active_record/base.rb |   14 ++++++++++++++
 activerecord/test/cases/finder_test.rb |   10 ++++++++++
 2 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 8fca34e..0fb9254 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -196,6 +196,10 @@ module ActiveRecord #:nodoc:
   #
   #   Student.find(:all, :conditions => { :grade => [9,11,12] })
   #
+  # You can also use assocation names for belongs_to assocations. For example, if Student <tt>belongs_to</tt> University
+  #
+  #   Student.find(:all, :conditions => { :university => victoria_wellington })
+  #
   # == Overwriting default accessors
   #
   # All column values are automatically available through basic accessors on the Active Record object, but sometimes you
@@ -2002,6 +2006,9 @@ module ActiveRecord #:nodoc:
         # And for value objects on a composed_of relationship:
         #   { :address => Address.new("123 abc st.", "chicago") }
         #     # => "address_street='123 abc st.' and address_city='chicago'"
+        # There's also some sugar built in for belongs_to associations
+        #   { :person  => 4 }
+        #     # => "person_id= 4"
         def sanitize_sql_hash_for_conditions(attrs)
           attrs = expand_hash_conditions_for_aggregates(attrs)
 
@@ -2015,6 +2022,13 @@ module ActiveRecord #:nodoc:
             else
               table_name = quoted_table_name
             end
+          
+            unless column_names.include?(attr) 
+              # Lookup the foreign key for belongs_to associations
+              if reflection = reflect_on_all_associations(:belongs_to).find { |a| a.name.to_s == attr }
+                attr = reflection.association_foreign_key
+              end
+            end
 
             "#{table_name}.#{connection.quote_column_name(attr)} #{attribute_condition(value)}"
           end.join(' AND ')
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index 80936d5..7131173 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -207,6 +207,16 @@ class FinderTest < ActiveRecord::TestCase
     }
   end
 
+  def test_find_on_hash_conditions_with_belongs_to_sugar
+    david = authors(:david)
+    assert Post.find(:first, :conditions => { :author => david })
+  
+    # test we still fall through
+    assert_raises(ActiveRecord::StatementInvalid) do
+      Post.find(:first, :conditions => { :this_is_not_a_column_name => "fubar"})
+    end
+  end
+
   def test_find_on_association_proxy_conditions
     assert_equal [1, 2, 3, 5, 6, 7, 8, 9, 10], Comment.find_all_by_post_id(authors(:david).posts).map(&:id).sort
   end
-- 
1.5.3.7