Fixed query cache when multiple database connections were involved

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6195 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/query_cache.rb

@@ -73,13 +73,13 @@ class << self
       alias_method :connection_without_query_cache, :connection
 
       def query_caches
-        (Thread.current[:query_cache] ||= {})
+        Thread.current["query_cache_#{connection_without_query_cache.object_id}"] ||= {}
       end
 
       def query_cache
         if query_caches[self]
           query_caches[self]
-        elsif superclass.respond_to?(:query_cache)
+        elsif superclass.respond_to?(:query_cache) and superclass.respond_to?(:connection) and superclass.connection_without_query_cache == connection_without_query_cache
           superclass.query_cache
         end
       end

activerecord/test/query_cache_test.rb

@@ -2,6 +2,7 @@
 require 'fixtures/topic'
 require 'fixtures/reply'
 require 'fixtures/task'
+require 'fixtures/course'
 
 class QueryCacheTest < Test::Unit::TestCase
   fixtures :tasks
@@ -43,6 +44,16 @@ def test_cache_is_scoped_on_all_descending_classes
     end
   end
 
+  def test_cache_does_not_blow_up_other_connections
+    assert_not_equal Course.connection.object_id, Task.connection.object_id, 
+        "Connections should be different, Course connects to a different database"
+
+    ActiveRecord::Base.cache do
+      assert_not_equal Course.connection.object_id, Task.connection.object_id, 
+          "Connections should be different, Course connects to a different database"
+    end
+  end
+
 
 end