[IMP] website_mail: avoid marking old messages as published

There is semantically no reason to publish old
messages, and doing so can be expensive for large
databases. Defaulting new messages to published
makes sense depending on the model on which they
are attached, so it might be better to improve
this as an opt-in handled in create() or
message_post() or via default_* context keys.

bzr revid: odo@openerp.com-20140217142006-ik18uqy9ewhhhb42

addons/website_mail/models/mail_message.py

@@ -28,13 +28,21 @@ class MailMessage(osv.Model):
 
     _columns = {
         'website_published': fields.boolean(
-            'Publish', help="Publish on the website as a blog"
+            'Published', help="Visible on the website as a comment"
         ),
     }
 
-    _defaults = {
-        'website_published': True,
-    }
+    def default_get(self, cr, uid, fields_list, context=None):
+        defaults = super(MailMessage, self).default_get(cr, uid, fields_list, context=context)
+
+        # Note: explicitly implemented in default_get() instead of _defaults,
+        # to avoid setting to True for all existing messages during upgrades.
+        # TODO: this default should probably be dynamic according to the model
+        # on which the messages are attached, thus moved to create().
+        if 'website_published' in fields_list:
+            defaults.setdefault('website_published', True)
+
+        return defaults
 
     def _search(self, cr, uid, args, offset=0, limit=None, order=None,
                 context=None, count=False, access_rights_uid=None):