#7 — getPreviousViewUrl fails when previous month has less days

The problem with the getPreviousViewUrl (and the getNextViewUrl) is that it expects the previous month to have the same amount of days as the current month. When I go to a calendar on July, 31 it is expecting there to be a June, 31. Here is what gets called:

return self._get_view_url_for_date(date(year, month, day))
return self._get_view_url_for_date(date(2008, 6, 31))

Which results in a ValueError since June only has 30 days. Oh and don't forget about leap year :)

Software stack:

python 2.4.5
Zope 2.10.5
Plone 3.0.6
dateable.chronos 0.3 (testing on trunk)

Here is the traceback:

2008-07-31 15:28:33 ERROR Zope.SiteErrorLog http://localhost:51056/project/mastercalendar/month.html
Traceback (innermost last):
  Module ZPublisher.Publish, line 119, in publish
  Module ZPublisher.mapply, line 88, in mapply
  Module Products.PDBDebugMode.pdbzope.runcall, line 60, in pdb_runcall
  Module ZPublisher.Publish, line 42, in call_object
  Module Products.Five.browser.metaconfigure, line 417, in __call__
  Module Shared.DC.Scripts.Bindings, line 313, in __call__
  Module Shared.DC.Scripts.Bindings, line 350, in _bindAndExec
  Module Products.PageTemplates.PageTemplateFile, line 129, in _exec
  Module Products.PTProfiler.ProfilerPatch, line 83, in __patched_render__
  Module Products.PageTemplates.PageTemplate, line 89, in pt_render
  Module zope.pagetemplate.pagetemplate, line 117, in pt_render
  Module zope.tal.talinterpreter, line 271, in __call__
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 891, in do_useMacro
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 536, in do_optTag_tal
  Module zope.tal.talinterpreter, line 521, in do_optTag
  Module zope.tal.talinterpreter, line 516, in no_tag
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 891, in do_useMacro
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 536, in do_optTag_tal
  Module zope.tal.talinterpreter, line 521, in do_optTag
  Module zope.tal.talinterpreter, line 516, in no_tag
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 957, in do_defineSlot
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 536, in do_optTag_tal
  Module zope.tal.talinterpreter, line 521, in do_optTag
  Module zope.tal.talinterpreter, line 516, in no_tag
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 861, in do_defineMacro
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 949, in do_defineSlot
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 536, in do_optTag_tal
  Module zope.tal.talinterpreter, line 521, in do_optTag
  Module zope.tal.talinterpreter, line 516, in no_tag
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 949, in do_defineSlot
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 536, in do_optTag_tal
  Module zope.tal.talinterpreter, line 521, in do_optTag
  Module zope.tal.talinterpreter, line 516, in no_tag
  Module zope.tal.talinterpreter, line 346, in interpret
  Module zope.tal.talinterpreter, line 408, in do_startTag
  Module zope.tal.talinterpreter, line 485, in attrAction_tal
  Module Products.PageTemplates.Expressions, line 228, in evaluateText
  Module zope.tales.tales, line 696, in evaluate
   - URL: index
   - Line 36, Column 20
   - Expression: <PathExpr standard:'view/getPreviousViewUrl'>
   - Names:
      {'container': <ATTopic at /project/mastercalendar>,
       'context': <ATTopic at /project/mastercalendar>,
       'default': <object object at 0x2a528>,
       'here': <ATTopic at /project/mastercalendar>,
       'loop': {},
       'nothing': None,
       'options': {'args': (<Products.Five.metaclass.SimpleViewClass from /path/to/project/project-buildout/src/dateable.chronos/dateable/chronos/browser/month.pt object at 0x728f510>,)},
       'repeat': <Products.PageTemplates.Expressions.SafeMapping object at 0x72a8530>,
       'request': <HTTPRequest, URL=http://localhost:51056/[…]/month.html>,
       'root': <Application at >,
       'template': <ImplicitAcquirerWrapper object at 0x728ff10>,
       'traverse_subpath': [],
       'user': <PropertiedUser 'admin'>,
       'view': <Products.Five.metaclass.SimpleViewClass from /path/to/project/project-buildout/src/dateable.chronos/dateable/chronos/browser/month.pt object at 0x728f510>,
       'views': <zope.app.pagetemplate.viewpagetemplatefile.ViewMapper object at 0x7294090>}
  Module Products.PTProfiler.ProfilerPatch, line 32, in __patched_call__
  Module zope.tales.expressions, line 217, in __call__
  Module Products.PageTemplates.Expressions, line 161, in _eval
  Module Products.PageTemplates.Expressions, line 123, in render
  Module dateable.chronos.browser.month, line 145, in getPreviousViewUrl
ValueError: day is out of range for month