Macro TracJSGanttChart fails when using Trac 1.1.1's date ticket fields

[jspohr@…]

Set custom ticket fields userstart and userfinish to "time":

userfinish = time
userfinish.format = date
userfinish.label = Due Date
userstart = time
userstart.format = date
userstart.label = Start Date

to get a nice date chooser widget with Trac 1.1.1. When displaying a JsGantt chart with a date entered into either field, this error is triggered:

2013-03-19 17:42:13,023 Trac[formatter] ERROR: Macro TracJSGanttChart(milestone=Milestone 1) failed: 
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.1.1-py2.7.egg/trac/wiki/formatter.py", line 765, in _macro_formatter
    return macro.ensure_inline(macro.process(args))
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.1.1-py2.7.egg/trac/wiki/formatter.py", line 356, in process
    text = self.processor(text)
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.1.1-py2.7.egg/trac/wiki/formatter.py", line 343, in _macro_processor
    text)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracjsgantt.py", line 727, in expand_macro
    tasks = self._add_tasks(options)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracjsgantt.py", line 662, in _add_tasks
    self.pm.computeSchedule(options, self.tickets)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1027, in computeSchedule
    self.scheduler.scheduleTasks(options, ticketsByID)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1893, in scheduleTasks
    serialSGS(_schedule_task_asap, 'npred', 0, self.pm.successors)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1850, in serialSGS
    scheduleFunction(ticket)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1602, in _schedule_task_asap
    if self.pm.isSet(t, 'start'):
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 247, in isSet
    and len(ticket[self.fields[field]]) != 0:
TypeError: object of type 'datetime.datetime' has no len()

Changing the type of the field to "text", the error changes to:

2013-03-19 17:57:01,380 Trac[formatter] ERROR: Macro TracJSGanttChart(milestone=Milestone 1) failed: 
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.1.1-py2.7.egg/trac/wiki/formatter.py", line 765, in _macro_formatter
    return macro.ensure_inline(macro.process(args))
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.1.1-py2.7.egg/trac/wiki/formatter.py", line 356, in process
    text = self.processor(text)
  File "/usr/local/lib/python2.7/dist-packages/Trac-1.1.1-py2.7.egg/trac/wiki/formatter.py", line 343, in _macro_processor
    text)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracjsgantt.py", line 727, in expand_macro
    tasks = self._add_tasks(options)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracjsgantt.py", line 662, in _add_tasks
    self.pm.computeSchedule(options, self.tickets)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1027, in computeSchedule
    self.scheduler.scheduleTasks(options, ticketsByID)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1893, in scheduleTasks
    serialSGS(_schedule_task_asap, 'npred', 0, self.pm.successors)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1850, in serialSGS
    scheduleFunction(ticket)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 1604, in _schedule_task_asap
    start = self.pm.parseStart(t)
  File "/usr/local/lib/python2.7/dist-packages/Trac_jsGantt-0.10_r12565-py2.7.egg/tracjsgantt/tracpm.py", line 276, in parseStart
    self.dbDateFormat))
TracError: Ticket 4999 has an invalid userstart value, "001363647600000000". It should match the format "%Y-%m-%d".