event_listing with end date query from collection

[petschki]

Scenario:
Collection which should show events with their end date in the future as event_listing

What I expect:
Events are listed which are ending in ther future (already started events should be listed!)

What happens:

raceback (innermost last):
  Module ZPublisher.WSGIPublisher, line 167, in transaction_pubevents
  Module ZPublisher.WSGIPublisher, line 376, in publish_module
  Module ZPublisher.WSGIPublisher, line 271, in publish
  Module ZPublisher.mapply, line 85, in mapply
  Module ZPublisher.WSGIPublisher, line 68, in call_object
  Module zope.browserpage.simpleviewclass, line 41, in __call__
  Module Products.Five.browser.pagetemplatefile, line 126, in __call__
  Module Products.Five.browser.pagetemplatefile, line 58, in __call__
  Module zope.pagetemplate.pagetemplate, line 133, in pt_render
  Module Products.PageTemplates.engine, line 365, in __call__
  Module z3c.pt.pagetemplate, line 176, in render
  Module chameleon.zpt.template, line 302, in render
  Module chameleon.template, line 215, in render
  Module chameleon.utils, line 53, in raise_with_traceback
  Module chameleon.template, line 192, in render
  Module 6c4d0c78d5d05de63fbc2acfb0fb59c9, line 1067, in render
  Module b9fb2a6a0cab7fe0c1c938dc331cbdc8, line 880, in render_master
  Module b9fb2a6a0cab7fe0c1c938dc331cbdc8, line 1503, in render_content
  Module 6c4d0c78d5d05de63fbc2acfb0fb59c9, line 1052, in __fill_content_core
  Module 6c4d0c78d5d05de63fbc2acfb0fb59c9, line 140, in render_content_core
  Module zope.tales.expressions, line 250, in __call__
  Module Products.PageTemplates.Expressions, line 221, in _eval
  Module Products.PageTemplates.Expressions, line 152, in render
  Module plone.memoize.view, line 59, in memogetter
  Module plone.app.event.browser.event_listing, line 171, in events
  Module plone.app.event.base, line 285, in expand_events
  Module DateTime.DateTime, line 1372, in lessThanEqualTo
TypeError: '<=' not supported between instances of 'int' and 'datetime.datetime'

Investigation:
The start/end range perparer in @@event_listing view somehow gets DateTime as start if you only have end in your query ... more digging needed

[petschki]

There are also a few other issues with start/end boundaries which @ksuess and me noticed here plone/plone.app.standardtiles#125 ... we also like to implement the limit to expand_events somehow, but this needs more investigations.

/cc @thet you might have more insights for us to get on track ...