Better exception if multiple translations for same language are found

[adrianschulz]

I noticed some weird behavior for some of my translated pages:

• No translation is shown in "Manage Translations"
• But adding a translation is not possible (error in Backend).

Also, I had problems with rejecting working copies (from plone.app.iterate).

In the logs there was the following error message:

instance8e.log-Traceback (innermost last):
instance8e.log-  Module ZPublisher.WSGIPublisher, line 156, in transaction_pubevents
instance8e.log-  Module ZPublisher.WSGIPublisher, line 338, in publish_module
instance8e.log-  Module ZPublisher.WSGIPublisher, line 256, in publish
instance8e.log-  Module ZPublisher.mapply, line 85, in mapply
instance8e.log-  Module ZPublisher.WSGIPublisher, line 62, in call_object
instance8e.log-  Module plone.z3cform.layout, line 63, in __call__
instance8e.log-  Module plone.z3cform.layout, line 47, in update
instance8e.log-  Module plone.dexterity.browser.edit, line 58, in update
instance8e.log-  Module plone.z3cform.fieldsets.extensible, line 65, in update
instance8e.log-  Module plone.z3cform.patch, line 30, in GroupForm_update
instance8e.log-  Module z3c.form.group, line 145, in update
instance8e.log-  Module plone.app.z3cform.csrf, line 22, in execute
instance8e.log-  Module z3c.form.action, line 98, in execute
instance8e.log-  Module z3c.form.button, line 315, in __call__
instance8e.log-  Module z3c.form.button, line 170, in __call__
instance8e.log-  Module plone.dexterity.browser.edit, line 30, in handleApply
instance8e.log-  Module z3c.form.group, line 126, in applyChanges
instance8e.log-  Module zope.event, line 32, in notify
instance8e.log-  Module zope.component.event, line 27, in dispatch
instance8e.log-  Module zope.component._api, line 124, in subscribers
instance8e.log-  Module zope.interface.registry, line 442, in subscribers
instance8e.log-  Module zope.interface.adapter, line 607, in subscribers
instance8e.log-  Module zope.component.event, line 36, in objectEventNotify
instance8e.log-  Module zope.component._api, line 124, in subscribers
instance8e.log-  Module zope.interface.registry, line 442, in subscribers
instance8e.log-  Module zope.interface.adapter, line 607, in subscribers
instance8e.log-  Module plone.app.multilingual.dx.subscriber, line 49, in __call__
instance8e.log-  Module plone.app.multilingual.dx.subscriber, line 87, in handle_modified
instance8e.log-  Module plone.app.multilingual.dx.cloner, line 63, in copy_fields
instance8e.log:AttributeError: 'NoneType' object has no attribute 'get_language'

I investigated further (with debug-mode) and noticed that the page had two English translations. I don't know how this happened but as you see in the debug-output, this is the current state.

>>> from plone.app.multilingual.interfaces import ITranslationManager
>>> from Products.CMFCore.utils import getToolByName
>>> from plone.app.multilingual.dx.subscriber import LanguageIndependentModifier
>>> reg_org = app.Plone.de.studium.wirtschaft.reglemente
>>> site = app.Plone
>>> tm  = ITranslationManager(reg_org)
>>> cat = getToolByName(site, 'portal_catalog')
>>> lim = LanguageIndependentModifier()
>>> tm.get_translations()
{'en': <Folder at /Plone/en/degree-programmes/business/regulations/media>, 'de': <FolderishDocument at /Plone/de/studium/wirtschaft/reglemente>}
>>> tm.get_translation('en')
>>> lim.get_all_translations(reg_org)
['en']
>>> brains = cat.searchResults(TranslationGroup=tm.tg, Language='en')
>>> ['%s - %s' % (brain.Language, brain.getPath()) for brain in brains]
['en - /Plone/en/degree-programmes/business/regulations', 'en - /Plone/en/degree-programmes/business/regulations/media']

It's definitely not normal to have two translations for the same language. But what I wished for was a better error message.