Fixed cache behavior so we don't touch the cache within Database.save() if

there's no commit flag. Then, when Database.commit() is called, any pending
saves are put into the cache.

controller/Database.py

@@ -7,6 +7,15 @@ import random
 from model.Persistent import Persistent
 
 
+class Connection_wrapper( object ):
+  def __init__( self, connection ):
+    self.connection = connection
+    self.pending_saves = []
+
+  def __getattr__( self, name ):
+    return getattr( self.connection, name )
+
+
 class Database( object ):
   ID_BITS = 128 # number of bits within an id
   ID_DIGITS = "0123456789abcdefghijklmnopqrstuvwxyz"
@@ -26,6 +35,15 @@ class Database( object ):
     # makes SQLite angry.
     os.putenv( "PGTZ", "UTC" )
 
+    # forcibly replace psycopg's connect() function with another function that returns the psycopg
+    # connection wrapped in a class with a pending_saves member, used in save() and commit() below
+    original_connect = psycopg.connect
+
+    def connect( *args, **kwargs ):
+      return Connection_wrapper( original_connect( *args, **kwargs ) )
+
+    psycopg.connect = connect
+
     if connection:
       self.__connection = connection
       self.__pool = None
@@ -72,15 +90,21 @@ class Database( object ):
 
     if commit:
       connection.commit()
-
-    # FIXME: we shouldn't touch the cache unless there's actually a commit.
-    # the problem is that in self.commit() below, we don't know which objects
-    # to actually save into the cache
-    if self.__cache:
-      self.__cache.set( obj.cache_key, obj )
+      if self.__cache:
+        self.__cache.set( obj.cache_key, obj )
+    else:
+      # no commit yet, so don't touch the cache
+      connection.pending_saves.append( obj )
 
   def commit( self ):
-    self.__get_connection().commit()
+    connection = self.__get_connection()
+    connection.commit()
+
+    # save any pending saves to the cache
+    for obj in connection.pending_saves:
+      self.__cache.set( obj.cache_key, obj )
+
+    connection.pending_saves = []
 
   def load( self, Object_type, object_id, revision = None ):
     """