[IMP] ir.translation, raise exception when trying to translate fields when no extra language is installed.

bzr revid: fme@openerp.com-20121106162753-6eqbhnwqhjgeun78

openerp/addons/base/ir/ir_translation.py

@@ -24,6 +24,7 @@ import logging
 
 import openerp.modules
 from openerp.osv import fields, osv
+from tools.translate import _
 
 _logger = logging.getLogger(__name__)
 
@@ -336,6 +337,8 @@ class ir_translation(osv.osv):
         trans_model = self.pool.get(model)
         domain = ['&', ('res_id', '=', id), ('name', '=like', model + ',%')]
         langs_ids = self.pool.get('res.lang').search(cr, uid, [('code', '!=', 'en_US')], context=context)
+        if not langs_ids:
+            raise osv.except_osv(_('Error'), _("Translation features are unavailable until you install an extra OpenERP translation."))
         langs = [lg.code for lg in self.pool.get('res.lang').browse(cr, uid, langs_ids, context=context)]
         main_lang = 'en_US'
         translatable_fields = []