Fix a few remaining tz naive dates

And remove redundant but != date parsing methods. In process make
the general parsing function less lenient (don't default date nor
month)

CHANGELOG.rst

@@ -34,6 +34,9 @@ Blades: Staff debug info is now accessible for Graphical Slider Tool problems.
 Blades: For Video Alpha the events ready, play, pause, seek, and speed change
 are logged on the server (in the logs). 
 
+Common: all dates and times are not time zone aware datetimes. No code should create or use struct_times nor naive
+datetimes.
+
 Common: Developers can now have private Django settings files.
 
 Common: Safety code added to prevent anything above the vertical level in the

common/lib/xmodule/xmodule/course_module.py

@@ -10,7 +10,6 @@ import dateutil.parser
 
 from xmodule.modulestore import Location
 from xmodule.seq_module import SequenceDescriptor, SequenceModule
-from xmodule.timeparse import parse_time
 from xmodule.util.decorators import lazyproperty
 from xmodule.graders import grader_from_conf
 import json
@@ -645,8 +644,11 @@ class CourseDescriptor(CourseFields, SequenceDescriptor):
     def start_date_text(self):
         def try_parse_iso_8601(text):
             try:
-                result = datetime.strptime(text, "%Y-%m-%dT%H:%M")
-                result = result.strftime("%b %d, %Y")
+                result = Date().from_json(text)
+                if result is None:
+                    result = text.title()
+                else:
+                    result = result.strftime("%b %d, %Y")
             except ValueError:
                 result = text.title()
 
@@ -670,8 +672,10 @@ class CourseDescriptor(CourseFields, SequenceDescriptor):
 
     @property
     def forum_posts_allowed(self):
+        datestandin = Date()
         try:
-            blackout_periods = [(parse_time(start), parse_time(end))
+            blackout_periods = [(datestandin.from_json(start),
+                                 datestandin.from_json(end))
                                 for start, end
                                 in self.discussion_blackouts]
             now = datetime.now(UTC())
@@ -701,7 +705,7 @@ class CourseDescriptor(CourseFields, SequenceDescriptor):
             if self.last_eligible_appointment_date is None:
                 raise ValueError("Last appointment date must be specified")
             self.registration_start_date = (self._try_parse_time('Registration_Start_Date') or
-                datetime.utcfromtimestamp(0))
+                datetime.fromtimestamp(0, UTC()))
             self.registration_end_date = self._try_parse_time('Registration_End_Date') or self.last_eligible_appointment_date
             # do validation within the exam info:
             if self.registration_start_date > self.registration_end_date:
@@ -720,7 +724,7 @@ class CourseDescriptor(CourseFields, SequenceDescriptor):
             """
             if key in self.exam_info:
                 try:
-                    return parse_time(self.exam_info[key])
+                    return Date().from_json(self.exam_info[key])
                 except ValueError as e:
                     msg = "Exam {0} in course {1} loaded with a bad exam_info key '{2}': '{3}'".format(self.exam_name, self.course_id, self.exam_info[key], e)
                     log.warning(msg)

common/lib/xmodule/xmodule/fields.py

@@ -6,7 +6,7 @@ from xblock.core import ModelType
 import datetime
 import dateutil.parser
 
-from django.utils.timezone import UTC
+from pytz import UTC
 
 log = logging.getLogger(__name__)
 
@@ -15,6 +15,10 @@ class Date(ModelType):
     '''
     Date fields know how to parse and produce json (iso) compatible formats. Converts to tz aware datetimes.
     '''
+    # See note below about not defaulting these
+    CURRENT_YEAR = datetime.datetime.now(UTC).year
+    DEFAULT_DATE0 = datetime.datetime(CURRENT_YEAR, 1, 1, tzinfo=UTC)
+    DEFAULT_DATE1 = datetime.datetime(CURRENT_YEAR, 2, 2, tzinfo=UTC)
     def from_json(self, field):
         """
         Parse an optional metadata key containing a time: if present, complain
@@ -26,14 +30,21 @@ class Date(ModelType):
         elif field is "":
             return None
         elif isinstance(field, basestring):
-            result = dateutil.parser.parse(field)
+            # It's not trivial to replace dateutil b/c parsing timezones as Z, +03:30, -400 is hard in python
+            # however, we don't want dateutil to default the month or day (but some tests at least expect
+            # us to default year); so, we'll see if dateutil uses the defaults for these the hard way
+            result = dateutil.parser.parse(field, default=self.DEFAULT_DATE0)
+            result_other = dateutil.parser.parse(field, default=self.DEFAULT_DATE1)
+            if result != result_other:
+                log.warning("Field {0} is missing month or day".format(self._name, field))
+                return None
             if result.tzinfo is None:
-                result = result.replace(tzinfo=UTC())
+                result = result.replace(tzinfo=UTC)
             return result
         elif isinstance(field, (int, long, float)):
-            return datetime.datetime.fromtimestamp(field / 1000, UTC())
+            return datetime.datetime.fromtimestamp(field / 1000, UTC)
         elif isinstance(field, time.struct_time):
-            return datetime.datetime.fromtimestamp(time.mktime(field), UTC())
+            return datetime.datetime.fromtimestamp(time.mktime(field), UTC)
         elif isinstance(field, datetime.datetime):
             return field
         else:

common/lib/xmodule/xmodule/tests/test_fields.py

@@ -3,6 +3,7 @@ import datetime
 import unittest
 from django.utils.timezone import UTC
 from xmodule.fields import Date, Timedelta
+from xmodule.timeinfo import TimeInfo
 
 
 class DateTest(unittest.TestCase):
@@ -52,6 +53,7 @@ class DateTest(unittest.TestCase):
         self.assertEqual(
             datetime.datetime(current.year, 12, 4, 16, 30, tzinfo=UTC()),
             DateTest.date.from_json("December 4 16:30"))
+        self.assertIsNone(DateTest.date.from_json("12 12:00"))
 
     def test_to_json(self):
         '''
@@ -90,3 +92,12 @@ class TimedeltaTest(unittest.TestCase):
             '1 days 46799 seconds',
             TimedeltaTest.delta.to_json(datetime.timedelta(days=1, hours=12, minutes=59, seconds=59))
         )
+
+
+class TimeInfoTest(unittest.TestCase):
+    def test_time_info(self):
+        due_date = datetime.datetime(2000, 4, 14, 10, tzinfo=UTC())
+        grace_pd_string = '1 day 12 hours 59 minutes 59 seconds'
+        timeinfo = TimeInfo(due_date, grace_pd_string)
+        self.assertEqual(timeinfo.close_date,
+            due_date + Timedelta().from_json(grace_pd_string))

common/lib/xmodule/xmodule/timeinfo.py

-from .timeparse import parse_timedelta
-
 import logging
+from xmodule.fields import Timedelta
 log = logging.getLogger(__name__)
 
 class TimeInfo(object):
@@ -14,6 +13,7 @@ class TimeInfo(object):
         self.close_date - the real due date
 
     """
+    _delta_standin = Timedelta()
     def __init__(self, due_date, grace_period_string):
         if due_date is not None:
             self.display_due_date = due_date
@@ -23,7 +23,7 @@ class TimeInfo(object):
 
         if grace_period_string is not None and self.display_due_date:
             try:
-                self.grace_period = parse_timedelta(grace_period_string)
+                self.grace_period = TimeInfo._delta_standin.from_json(grace_period_string)
                 self.close_date = self.display_due_date + self.grace_period
             except:
                 log.error("Error parsing the grace period {0}".format(grace_period_string))

common/lib/xmodule/xmodule/timeparse.py

-"""
-Helper functions for handling time in the format we like.
-"""
-import re
-from datetime import timedelta, datetime
-
-TIME_FORMAT = "%Y-%m-%dT%H:%M"
-
-TIMEDELTA_REGEX = re.compile(r'^((?P<days>\d+?) day(?:s?))?(\s)?((?P<hours>\d+?) hour(?:s?))?(\s)?((?P<minutes>\d+?) minute(?:s)?)?(\s)?((?P<seconds>\d+?) second(?:s)?)?$')
-
-def parse_time(time_str):
-    """
-    Takes a time string in TIME_FORMAT
-
-    Returns it as a time_struct.
-
-    Raises ValueError if the string is not in the right format.
-    """
-    return datetime.strptime(time_str, TIME_FORMAT)
-
-
-def stringify_time(dt):
-    """
-    Convert a datetime struct to a string
-    """
-    return dt.isoformat()
-
-def parse_timedelta(time_str):
-    """
-    time_str: A string with the following components:
-        <D> day[s] (optional)
-        <H> hour[s] (optional)
-        <M> minute[s] (optional)
-        <S> second[s] (optional)
-
-    Returns a datetime.timedelta parsed from the string
-    """
-    parts = TIMEDELTA_REGEX.match(time_str)
-    if not parts:
-        return
-    parts = parts.groupdict()
-    time_params = {}
-    for (name, param) in parts.iteritems():
-        if param:
-            time_params[name] = int(param)
-    return timedelta(**time_params)