Fixed #17262 -- Refactored tzinfo implementations.

This commit deprecates django.utils.tzinfo in favor of the more recent
django.utils.timezone which was introduced when Django gained support
for time zones.

django/utils/timezone.py

@@ -18,7 +18,8 @@ from django.conf import settings
 from django.utils import six
 
 __all__ = [
-    'utc', 'get_default_timezone', 'get_current_timezone',
+    'utc', 'get_fixed_timezone',
+    'get_default_timezone', 'get_current_timezone',
     'activate', 'deactivate', 'override',
     'is_naive', 'is_aware', 'make_aware', 'make_naive',
 ]
@@ -47,19 +48,45 @@ class UTC(tzinfo):
     def dst(self, dt):
         return ZERO
 
+class FixedOffset(tzinfo):
+    """
+    Fixed offset in minutes east from UTC. Taken from Python's docs.
+
+    Kept as close as possible to the reference version. __init__ was changed
+    to make its arguments optional, according to Python's requirement that
+    tzinfo subclasses can be instantiated without arguments.
+    """
+
+    def __init__(self, offset=None, name=None):
+        if offset is not None:
+            self.__offset = timedelta(minutes=offset)
+        if name is not None:
+            self.__name = name
+
+    def utcoffset(self, dt):
+        return self.__offset
+
+    def tzname(self, dt):
+        return self.__name
+
+    def dst(self, dt):
+        return ZERO
+
 class ReferenceLocalTimezone(tzinfo):
     """
-    Local time implementation taken from Python's docs.
+    Local time. Taken from Python's docs.
 
     Used only when pytz isn't available, and most likely inaccurate. If you're
     having trouble with this class, don't waste your time, just install pytz.
 
-    Kept identical to the reference version. Subclasses contain improvements.
+    Kept as close as possible to the reference version. __init__ was added to
+    delay the computation of STDOFFSET, DSTOFFSET and DSTDIFF which is
+    performed at import time in the example.
+
+    Subclasses contain further improvements.
     """
 
     def __init__(self):
-        # This code is moved in __init__ to execute it as late as possible
-        # See get_default_timezone().
         self.STDOFFSET = timedelta(seconds=-_time.timezone)
         if _time.daylight:
             self.DSTOFFSET = timedelta(seconds=-_time.altzone)
@@ -68,9 +95,6 @@ class ReferenceLocalTimezone(tzinfo):
         self.DSTDIFF = self.DSTOFFSET - self.STDOFFSET
         tzinfo.__init__(self)
 
-    def __repr__(self):
-        return "<LocalTimezone>"
-
     def utcoffset(self, dt):
         if self._isdst(dt):
             return self.DSTOFFSET
@@ -84,8 +108,7 @@ class ReferenceLocalTimezone(tzinfo):
             return ZERO
 
     def tzname(self, dt):
-        is_dst = False if dt is None else self._isdst(dt)
+        return _time.tzname[self._isdst(dt)]
-        return _time.tzname[is_dst]
 
     def _isdst(self, dt):
         tt = (dt.year, dt.month, dt.day,
@@ -103,6 +126,10 @@ class LocalTimezone(ReferenceLocalTimezone):
     error message is helpful.
     """
 
+    def tzname(self, dt):
+        is_dst = False if dt is None else self._isdst(dt)
+        return _time.tzname[is_dst]
+
     def _isdst(self, dt):
         try:
             return super(LocalTimezone, self)._isdst(dt)
@@ -116,6 +143,17 @@ class LocalTimezone(ReferenceLocalTimezone):
 utc = pytz.utc if pytz else UTC()
 """UTC time zone as a tzinfo instance."""
 
+def get_fixed_timezone(offset):
+    """
+    Returns a tzinfo instance with a fixed offset from UTC.
+    """
+    if isinstance(offset, timedelta):
+        offset = offset.seconds // 60
+    sign = '-' if offset < 0 else '+'
+    hhmm = '%02d%02d' % divmod(abs(offset), 60)
+    name = sign + hhmm
+    return FixedOffset(offset, name)
+
 # In order to avoid accessing the settings at compile time,
 # wrap the expression in a function and cache the result.
 _localtime = None
@@ -125,8 +163,6 @@ def get_default_timezone():
     Returns the default time zone as a tzinfo instance.
 
     This is the time zone defined by settings.TIME_ZONE.
-
-    See also :func:`get_current_timezone`.
     """
     global _localtime
     if _localtime is None:

django/utils/tzinfo.py

@@ -2,11 +2,18 @@
 
 from __future__ import unicode_literals
 
-import time
 from datetime import timedelta, tzinfo
+import time
+import warnings
 
 from django.utils.encoding import force_str, force_text, DEFAULT_LOCALE_ENCODING
 
+warnings.warn(
+    "django.utils.tzinfo will be removed in Django 1.9. "
+    "Use django.utils.timezone instead.",
+    PendingDeprecationWarning)
+
+
 # Python's doc say: "A tzinfo subclass must have an __init__() method that can
 # be called with no arguments". FixedOffset and LocalTimezone don't honor this
 # requirement. Defining __getinitargs__ is sufficient to fix copy/deepcopy as
@@ -15,6 +22,10 @@ from django.utils.encoding import force_str, force_text, DEFAULT_LOCALE_ENCODING
 class FixedOffset(tzinfo):
     "Fixed offset in minutes east from UTC."
     def __init__(self, offset):
+        warnings.warn(
+            "django.utils.tzinfo.FixedOffset will be removed in Django 1.9. "
+            "Use django.utils.timezone.get_fixed_timezone instead.",
+            PendingDeprecationWarning)
         if isinstance(offset, timedelta):
             self.__offset = offset
             offset = self.__offset.seconds // 60
@@ -48,6 +59,10 @@ class FixedOffset(tzinfo):
 class LocalTimezone(tzinfo):
     "Proxy timezone information from time module."
     def __init__(self, dt):
+        warnings.warn(
+            "django.utils.tzinfo.LocalTimezone will be removed in Django 1.9. "
+            "Use django.utils.timezone.get_default_timezone instead.",
+            PendingDeprecationWarning)
         tzinfo.__init__(self)
         self.__dt = dt
         self._tzname = self.tzname(dt)

docs/internals/deprecation.txt

@@ -417,6 +417,8 @@ these changes.
 
 * ``django.utils.importlib`` will be removed.
 
+* ``django.utils.tzinfo`` will be removed.
+
 * ``django.utils.unittest`` will be removed.
 
 * The ``syncdb`` command will be removed.

docs/ref/utils.txt

@@ -927,6 +927,17 @@ For a complete discussion on the usage of the following see the
 
     :class:`~datetime.tzinfo` instance that represents UTC.
 
+.. function:: get_fixed_timezone(offset)
+
+    .. versionadded:: 1.7
+
+    Returns a :class:`~datetime.tzinfo` instance that represents a time zone
+    with a fixed offset from UTC.
+
+    ``offset`` is a :class:`datetime.timedelta` or an integer number of
+    minutes. Use positive values for time zones east of UTC and negative
+    values for west of UTC.
+
 .. function:: get_default_timezone()
 
     Returns a :class:`~datetime.tzinfo` instance that represents the
@@ -1021,6 +1032,9 @@ For a complete discussion on the usage of the following see the
 ``django.utils.tzinfo``
 =======================
 
+.. deprecated:: 1.7
+    Use :mod:`~django.utils.timezone` instead.
+
 .. module:: django.utils.tzinfo
    :synopsis: Implementation of ``tzinfo`` classes for use with ``datetime.datetime``.
 
@@ -1028,6 +1042,12 @@ For a complete discussion on the usage of the following see the
 
     Fixed offset in minutes east from UTC.
 
+    .. deprecated:: 1.7
+        Use :func:`~django.utils.timezone.get_fixed_timezone` instead.
+
 .. class:: LocalTimezone
 
     Proxy timezone information from time module.
+
+    .. deprecated:: 1.7
+        Use :func:`~django.utils.timezone.get_default_timezone` instead.

docs/releases/1.7.txt

@@ -308,6 +308,16 @@ For apps with migrations, ``allow_migrate`` will now get passed
 without custom attributes, methods or managers. Make sure your ``allow_migrate``
 methods are only referring to fields or other items in ``model._meta``.
 
+pytz may be required
+~~~~~~~~~~~~~~~~~~~~
+
+If your project handles datetimes before 1970 or after 2037 and Django raises
+a :exc:`~exceptions.ValueError` when encountering them, you will have to
+install pytz_. You may be affected by this problem if you use Django's time
+zone-related date formats or :mod:`django.contrib.syndication`.
+
+.. _pytz: https://pypi.python.org/pypi/pytz/
+
 Miscellaneous
 ~~~~~~~~~~~~~
 
@@ -389,6 +399,15 @@ Features deprecated in 1.7
 respectively :mod:`logging.config` and :mod:`importlib` provided for Python
 versions prior to 2.7. They have been deprecated.
 
+``django.utils.tzinfo``
+~~~~~~~~~~~~~~~~~~~~~~~
+
+``django.utils.tzinfo`` provided two :class:`~datetime.tzinfo` subclasses,
+``LocalTimezone`` and ``FixedOffset``. They've been deprecated in favor of
+more correct alternatives provided by :mod:`django.utils.timezone`,
+:func:`django.utils.timezone.get_default_timezone` and
+:func:`django.utils.timezone.get_fixed_timezone`.
+
 ``django.utils.unittest``
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/timezones/tests.py

@@ -25,7 +25,6 @@ from django.test import TestCase, skipIfDBFeature, skipUnlessDBFeature
 from django.test.utils import override_settings
 from django.utils import six
 from django.utils import timezone
-from django.utils.tzinfo import FixedOffset
 
 from .forms import EventForm, EventSplitForm, EventModelForm
 from .models import Event, MaybeEvent, Session, SessionEvent, Timestamp, AllDayEvent
@@ -40,8 +39,8 @@ from .models import Event, MaybeEvent, Session, SessionEvent, Timestamp, AllDayE
 # 10:20:30 in UTC and 17:20:30 in ICT.
 
 UTC = timezone.utc
-EAT = FixedOffset(180)      # Africa/Nairobi
+EAT = timezone.get_fixed_timezone(180)      # Africa/Nairobi
-ICT = FixedOffset(420)      # Asia/Bangkok
+ICT = timezone.get_fixed_timezone(420)      # Asia/Bangkok
 
 TZ_SUPPORT = hasattr(time, 'tzset')
 

tests/utils_tests/test_timezone.py

@@ -6,11 +6,10 @@ import unittest
 from django.test.utils import override_settings
 from django.utils import six
 from django.utils import timezone
-from django.utils.tzinfo import FixedOffset
 
 
-EAT = FixedOffset(180)      # Africa/Nairobi
+EAT = timezone.get_fixed_timezone(180)      # Africa/Nairobi
-ICT = FixedOffset(420)      # Asia/Bangkok
+ICT = timezone.get_fixed_timezone(420)      # Asia/Bangkok
 
 
 class TimezoneTests(unittest.TestCase):

tests/utils_tests/test_tzinfo.py

@@ -4,10 +4,16 @@ import os
 import pickle
 import time
 import unittest
+import warnings
 
-from django.utils.tzinfo import FixedOffset, LocalTimezone
+from django.test.utils import IgnorePendingDeprecationWarningsMixin
 
-class TzinfoTests(unittest.TestCase):
+# Swallow the import-time warning to test the deprecated implementation.
+with warnings.catch_warnings():
+    warnings.filterwarnings("ignore", category=PendingDeprecationWarning)
+    from django.utils.tzinfo import FixedOffset, LocalTimezone
+
+class TzinfoTests(IgnorePendingDeprecationWarningsMixin, unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):