Index: openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.7.0d3-5.7.0d4.sql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.7.0d3-5.7.0d4.sql,v
diff -u -N -r1.1 -r1.2
--- openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.7.0d3-5.7.0d4.sql	11 Apr 2011 00:28:54 -0000	1.1
+++ openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.7.0d3-5.7.0d4.sql	24 Apr 2011 21:28:30 -0000	1.2
@@ -1,3 +1,6 @@
+-- Need to guard against xotcl-core which sneakily modifies core behind
+-- our backs (rather than having fixed acs-core like nice people would do)
+
 begin;
 
  select content_type__create_attribute (
@@ -9,7 +12,11 @@
    null,
    null,
    'integer'
- );
+ )
+ where not exists (select 1
+                   from acs_attributes
+                   where object_type = 'content_revision'
+                     and attribute_name = 'item_id');
 
  select content_type__create_attribute (
    'content_revision',
@@ -20,6 +27,10 @@
    null,
    null,
    'text'
- );
+ )
+ where not exists (select 1
+                   from acs_attributes
+                   where object_type = 'content_revision'
+                     and attribute_name = 'content');
 
 end;