tile edit view wrong context for vocabularies - plone

Question

I have a persistent tile that has a choice field:
subjects = schema.List(
title=_(u"Subjects"),
value_type=schema.Choice(
vocabulary='my.subjects'
),
)
but this is failing on edit view rendering like this:
2013-05-22 18:37:56 ERROR Zope.SiteErrorLog 1369240676.330.546121806344 http://localhost:8082/plumi/##edit-tile/tagcloud.tile/home-cloud
Traceback (innermost last):
Module ZPublisher.Publish, line 126, in publish
Module ZPublisher.mapply, line 77, in mapply
Module ZPublisher.Publish, line 46, in call_object
Module plone.z3cform.layout, line 70, in __call__
Module plone.z3cform.layout, line 54, in update
Module plone.app.tiles.browser.edit, line 48, in update
Module plone.app.tiles.browser.base, line 55, in update
Module plone.z3cform.fieldsets.extensible, line 59, in update
Module plone.z3cform.patch, line 30, in GroupForm_update
Module z3c.form.group, line 125, in update
Module plone.app.tiles.browser.base, line 71, in updateWidgets
Module z3c.form.field, line 275, in update
Module z3c.form.browser.orderedselect, line 50, in update
Module z3c.form.browser.widget, line 70, in update
Module z3c.form.widget, line 199, in update
Module z3c.form.widget, line 193, in updateTerms
Module zope.component._api, line 107, in getMultiAdapter
Module zope.component._api, line 120, in queryMultiAdapter
Module zope.component.registry, line 238, in queryMultiAdapter
Module zope.interface.adapter, line 532, in queryMultiAdapter
Module z3c.form.term, line 174, in CollectionTerms
Module zope.schema._field, line 352, in bind
Module Zope2.App.schema, line 33, in get
Module my.vocabularies, line 22, in __call__
Module Products.CMFCore.utils, line 10, in check_getToolByName
Module Products.CMFCore.utils, line 120, in getToolByName
AttributeError: portal_catalog
This happen because the context passed to the vocabulary call is the data dictionary of the tile. It happens also when using SearchableTextSourceBinder in another field:
source=SearchableTextSourceBinder(
{'is_folderish': True},
default_query='path:'
)
that makes plone.app.vocabularies.catalog fail:
Module plone.app.vocabularies.catalog, line 237, in __call__
Module plone.app.vocabularies.catalog, line 144, in __init__
Module Products.CMFCore.utils, line 10, in check_getToolByName
Module Products.CMFCore.utils, line 120, in getToolByName
AttributeError: portal_catalog

Answer 1

I don't know, if it's by design, but when a persistent tile is edited, context sensitive vocabulary will get its context (persistent tile data dictionary) without any acquisition wrapping. Therefore all lookups which rely on acquisition will fail.
You could try fixing your vocabulary to use portal root as its context for getToolByName-looksup using either plone.api.portal.get() or zope.component.hooks.getSite().
If you really need the current context, an ugly way would be to get zope.globalrequest.getRequest().get("PUBLISHED") which should be the current publishable context found by ZPublisher. It's usually a view, but you can get your context object from its acquisition chain. Of course, you should be very defensive with that approach.