Merge branch 'master' into sprockets

Conflicts:
	railties/lib/rails/application/configuration.rb

1 files changed, 22 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 426000fde1..8fa315bdf3 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -123,6 +123,12 @@ module ActiveRecord
       end
     end
 
+    # Same as +first+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found. Note that <tt>first!</tt> accepts no arguments.
+    def first!
+      first or raise RecordNotFound
+    end
+
     # A convenience wrapper for <tt>find(:last, *args)</tt>. You can pass in all the
     # same arguments to this method as you can to <tt>find(:last)</tt>.
     def last(*args)
@@ -137,6 +143,12 @@ module ActiveRecord
       end
     end
 
+    # Same as +last+ but raises <tt>ActiveRecord::RecordNotFound</tt> if no record
+    # is found. Note that <tt>last!</tt> accepts no arguments.
+    def last!
+      last or raise RecordNotFound
+    end
+
     # A convenience wrapper for <tt>find(:all, *args)</tt>. You can pass in all the
     # same arguments to this method as you can to <tt>find(:all)</tt>.
     def all(*args)
@@ -171,7 +183,9 @@ module ActiveRecord
     def exists?(id = nil)
       id = id.id if ActiveRecord::Base === id
 
-      relation = select("1").limit(1)
+      join_dependency = construct_join_dependency_for_association_find
+      relation = construct_relation_for_association_find(join_dependency)
+      relation = relation.except(:select).select("1").limit(1)
 
       case id
       when Array, Hash
@@ -180,14 +194,13 @@ module ActiveRecord
         relation = relation.where(table[primary_key].eq(id)) if id
       end
 
-      relation.first ? true : false
+      connection.select_value(relation.to_sql) ? true : false
     end
 
     protected
 
     def find_with_associations
-      including = (@eager_load_values + @includes_values).uniq
-      join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, [])
+      join_dependency = construct_join_dependency_for_association_find
       relation = construct_relation_for_association_find(join_dependency)
       rows = connection.select_all(relation.to_sql, 'SQL', relation.bind_values)
       join_dependency.instantiate(rows)
@@ -195,6 +208,11 @@ module ActiveRecord
       []
     end
 
+    def construct_join_dependency_for_association_find
+      including = (@eager_load_values + @includes_values).uniq
+      ActiveRecord::Associations::JoinDependency.new(@klass, including, [])
+    end
+
     def construct_relation_for_association_calculations
       including = (@eager_load_values + @includes_values).uniq
       join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, arel.froms.first)