[IMP] Cleanup and refactoring of exception handling

Unify and refactor exception handling in framework and addons.

The generic `except_osv` is now deprecated, and replaced by more specialized exception subtypes:
 - `UserError` (renamed from Warning, as it conflicts with the built-in `Warning`) raised when a non-technical error occurs during a business operation. It could be a missing information in the data provided by the user, or a misconfiguration.
 - `AccessError`: raised when any operation is denied because the user conducting it does not have the required access rights.
 - `AccessDenied`: raised when an operation that requires authenticated access is attempted via an unauthenticated request.
 - `MissingError`: raised when an operation is attempted on a record that does not exist.
 - `ValidationError`: raised when an operation violates a SQL or Python constraint.
 - All other exceptions are internal errors due to a system problem or bug, and raised untouched to the client-side, which should display a traceback.

All exceptions take a single message argument.

The `test_exceptions` module has been updated to showcase both new and old (deprecated) exceptions.

A great many old `except_osv` had a useless title with "Error!" or "Warning", those have been removed, as this is handled by the client-side widget that displays the messages.

This commit introduces a more consistent policy for logging errors and warnings:
 - All messages that do not require administrator attention should be logged at INFO level or lower. This includes all errors that are notified to the user in a friendly manner, even for access right problems or validation errors during business operations.
 - All messages that indicate a likely misconfiguration or malicious use by the users should be logged at WARNING level, as they typically require administrator attention.
 - All other unhandled internal errors cannot typically be handled by the user and should be logged at ERROR or higher level, as they require immediate administrator attention.

1 files changed, 5 insertions, 4 deletions

diff --git a/addons/mail/mail_message.py b/addons/mail/mail_message.py
index fe433657077..2780a659008 100644
--- a/addons/mail/mail_message.py
+++ b/addons/mail/mail_message.py
@@ -26,10 +26,11 @@ from openerp import tools
 from email.header import decode_header
 from email.utils import formataddr
 from openerp import SUPERUSER_ID, api
-from openerp.osv import osv, orm, fields
+from openerp.osv import osv, fields
 from openerp.tools import html_email_clean
 from openerp.tools.translate import _
 from HTMLParser import HTMLParser
+from openerp.exceptions import UserError, AccessError
 
 _logger = logging.getLogger(__name__)
 
@@ -174,7 +175,7 @@ class mail_message(osv.Model):
             return formataddr((this.name, '%s@%s' % (this.alias_name, this.alias_domain)))
         elif this.email:
             return formataddr((this.name, this.email))
-        raise osv.except_osv(_('Invalid Action!'), _("Unable to send email, please configure the sender's email address or alias."))
+        raise UserError(_("Unable to send email, please configure the sender's email address or alias."))
 
     def _get_default_author(self, cr, uid, context=None):
         return self.pool.get('res.users').browse(cr, SUPERUSER_ID, uid, context=context).partner_id.id
@@ -770,10 +771,10 @@ class mail_message(osv.Model):
         other_ids = other_ids.difference(set(document_related_ids))
         if not other_ids:
             return
-        raise orm.except_orm(_('Access Denied'),
-                             _('The requested operation cannot be completed due to security restrictions. Please contact your system administrator.\n\n(Document type: %s, Operation: %s)') %
+        raise AccessError(_('The requested operation cannot be completed due to security restrictions. Please contact your system administrator.\n\n(Document type: %s, Operation: %s)') %
                              (self._description, operation))
 
+
     def _get_record_name(self, cr, uid, values, context=None):
         """ Return the related document name, using name_get. It is done using
             SUPERUSER_ID, to be sure to have the record name correctly stored. """