Merge remote branch 'sven/master' into foo

* sven/master:
  don't leave @options uninitialized on Table
  revert 19c5a95 and add tests

lib/arel/engines/sql/relations/table.rb

@@ -31,7 +31,8 @@ def initialize(name, options = {})
           @table_alias = as unless as == @name
         end
       else
-        @engine = options # Table.new('foo', engine)
+        @engine  = options # Table.new('foo', engine)
+        @options = {}
       end
 
       if @engine.connection
@@ -50,6 +51,10 @@ def initialize(name, options = {})
       end
     end
 
+    def table_exists?
+      @table_exists ||= @@tables.include?(name) || engine.connection.table_exists?(name)
+    end
+
     def as(table_alias)
       Table.new(name, options.merge(:as => table_alias))
     end

spec/engines/sql/unit/relations/table_spec.rb

@@ -118,5 +118,28 @@ module Arel
         Table.new(:users, engine = Sql::Engine.new).engine.should == engine
       end
     end
+
+    describe 'lazy evaluation' do
+      before do
+        @relation = Table.new(:authors)
+        ActiveRecord::Base.connection.execute('CREATE TABLE authors (id INTEGER)')
+      end
+
+      after do
+        ActiveRecord::Base.connection.execute('DROP TABLE authors')
+      end
+
+      describe '#table_exists?' do
+        it 'detects a table that was created after the model has loaded' do
+          @relation.table_exists?.should be_true
+        end
+      end
+
+      describe '#attributes' do
+        it 'detects attributes from a table that was created after the model has loaded' do
+          @relation.attributes.should == [Attribute.new(@relation, :id)]
+        end
+      end
+    end
   end
 end