1 files changed, 19 insertions, 19 deletions
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index a2324039cf..52968070cb 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -124,7 +124,7 @@ module ActiveRecord
       # <tt>composed_of :balance, :class_name => 'Money'</tt> returns <tt>'Money'</tt>
       # <tt>has_many :clients</tt> returns <tt>'Client'</tt>
       def class_name
-        @class_name ||= options[:class_name] || derive_class_name
+        @class_name ||= (options[:class_name] || derive_class_name).to_s
       end
 
       # Returns +true+ if +self+ and +other_aggregation+ have the same +name+ attribute, +active_record+ attribute,
@@ -211,22 +211,20 @@ module ActiveRecord
         @association_foreign_key ||= options[:association_foreign_key] || class_name.foreign_key
       end
 
-      def association_primary_key
-        @association_primary_key ||=
-          options[:primary_key] ||
-          !options[:polymorphic] && klass.primary_key ||
-          'id'
+      # klass option is necessary to support loading polymorphic associations
+      def association_primary_key(klass = nil)
+        options[:primary_key] || primary_key(klass || self.klass)
       end
 
       def active_record_primary_key
-        @active_record_primary_key ||= options[:primary_key] || active_record.primary_key
+        @active_record_primary_key ||= options[:primary_key] || primary_key(active_record)
       end
 
       def counter_cache_column
         if options[:counter_cache] == true
           "#{active_record.name.demodulize.underscore.pluralize}_count"
         elsif options[:counter_cache]
-          options[:counter_cache]
+          options[:counter_cache].to_s
         end
       end
 
@@ -359,6 +357,10 @@ module ActiveRecord
             active_record.name.foreign_key
           end
         end
+
+        def primary_key(klass)
+          klass.primary_key || raise(UnknownPrimaryKey.new(klass))
+        end
     end
 
     # Holds all the meta-data about a :through association as it was specified
@@ -431,7 +433,7 @@ module ActiveRecord
       # of relevant reflections, plus any :source_type or polymorphic :as constraints.
       def conditions
         @conditions ||= begin
-          conditions = source_reflection.conditions
+          conditions = source_reflection.conditions.map { |c| c.dup }
 
           # Add to it the conditions from this reflection if necessary.
           conditions.first << options[:conditions] if options[:conditions]
@@ -463,17 +465,15 @@ module ActiveRecord
       # We want to use the klass from this reflection, rather than just delegate straight to
       # the source_reflection, because the source_reflection may be polymorphic. We still
       # need to respect the source_reflection's :primary_key option, though.
-      def association_primary_key
-        @association_primary_key ||= begin
-          # Get the "actual" source reflection if the immediate source reflection has a
-          # source reflection itself
-          source_reflection = self.source_reflection
-          while source_reflection.source_reflection
-            source_reflection = source_reflection.source_reflection
-          end
-
-          source_reflection.options[:primary_key] || klass.primary_key
+      def association_primary_key(klass = nil)
+        # Get the "actual" source reflection if the immediate source reflection has a
+        # source reflection itself
+        source_reflection = self.source_reflection
+        while source_reflection.source_reflection
+          source_reflection = source_reflection.source_reflection
         end
+
+        source_reflection.options[:primary_key] || primary_key(klass || self.klass)
       end
 
       # Gets an array of possible <tt>:through</tt> source reflection names: