Fixed #32366 -- Updated datetime module usage to recommended approach.

- Replaced datetime.utcnow() with datetime.now().
- Replaced datetime.utcfromtimestamp() with datetime.fromtimestamp().
- Replaced datetime.utctimetuple() with datetime.timetuple().
- Replaced calendar.timegm() and datetime.utctimetuple() with datetime.timestamp().

5 files changed, 13 insertions, 18 deletions

diff --git a/django/utils/dateformat.py b/django/utils/dateformat.py
index 4833b5af2c..0d4eb4bdf0 100644
--- a/django/utils/dateformat.py
+++ b/django/utils/dateformat.py
@@ -12,7 +12,6 @@ Usage:
 """
 import calendar
 import datetime
-import time
 from email.utils import format_datetime as format_datetime_rfc5322
 
 from django.utils.dates import (
@@ -20,7 +19,7 @@ from django.utils.dates import (
 )
 from django.utils.regex_helper import _lazy_re_compile
 from django.utils.timezone import (
-    _datetime_ambiguous_or_imaginary, get_default_timezone, is_aware, is_naive,
+    _datetime_ambiguous_or_imaginary, get_default_timezone, is_naive,
     make_aware,
 )
 from django.utils.translation import gettext as _
@@ -295,10 +294,10 @@ class DateFormat(TimeFormat):
 
     def U(self):
         "Seconds since the Unix epoch (January 1 1970 00:00:00 GMT)"
-        if isinstance(self.data, datetime.datetime) and is_aware(self.data):
-            return int(calendar.timegm(self.data.utctimetuple()))
-        else:
-            return int(time.mktime(self.data.timetuple()))
+        value = self.data
+        if not isinstance(value, datetime.datetime):
+            value = datetime.datetime.combine(value, datetime.time.min)
+        return int(value.timestamp())
 
     def w(self):
         "Day of the week, numeric, i.e. '0' (Sunday) to '6' (Saturday)"
diff --git a/django/utils/feedgenerator.py b/django/utils/feedgenerator.py
index f08e89b25c..24b2d1d172 100644
--- a/django/utils/feedgenerator.py
+++ b/django/utils/feedgenerator.py
@@ -172,8 +172,7 @@ class SyndicationFeed:
                     if latest_date is None or item_date > latest_date:
                         latest_date = item_date
 
-        # datetime.now(tz=utc) is slower, as documented in django.utils.timezone.now
-        return latest_date or datetime.datetime.utcnow().replace(tzinfo=utc)
+        return latest_date or datetime.datetime.now(tz=utc)
 
 
 class Enclosure:
diff --git a/django/utils/http.py b/django/utils/http.py
index 5397bb8190..6aa45a2cd6 100644
--- a/django/utils/http.py
+++ b/django/utils/http.py
@@ -1,5 +1,4 @@
 import base64
-import calendar
 import datetime
 import re
 import unicodedata
@@ -112,9 +111,10 @@ def parse_http_date(date):
     else:
         raise ValueError("%r is not in a valid HTTP date format" % date)
     try:
+        tz = datetime.timezone.utc
         year = int(m['year'])
         if year < 100:
-            current_year = datetime.datetime.utcnow().year
+            current_year = datetime.datetime.now(tz=tz).year
             current_century = current_year - (current_year % 100)
             if year - (current_year % 100) > 50:
                 # year that appears to be more than 50 years in the future are
@@ -127,8 +127,8 @@ def parse_http_date(date):
         hour = int(m['hour'])
         min = int(m['min'])
         sec = int(m['sec'])
-        result = datetime.datetime(year, month, day, hour, min, sec)
-        return calendar.timegm(result.utctimetuple())
+        result = datetime.datetime(year, month, day, hour, min, sec, tzinfo=tz)
+        return int(result.timestamp())
     except Exception as exc:
         raise ValueError("%r is not a valid date" % date) from exc
 
diff --git a/django/utils/timezone.py b/django/utils/timezone.py
index cf22ec34d0..bb2b6b9594 100644
--- a/django/utils/timezone.py
+++ b/django/utils/timezone.py
@@ -194,11 +194,7 @@ def now():
     """
     Return an aware or naive datetime.datetime, depending on settings.USE_TZ.
     """
-    if settings.USE_TZ:
-        # timeit shows that datetime.now(tz=utc) is 24% slower
-        return datetime.utcnow().replace(tzinfo=utc)
-    else:
-        return datetime.now()
+    return datetime.now(tz=utc if settings.USE_TZ else None)
 
 
 # By design, these four functions don't perform any checks on their arguments.
diff --git a/django/utils/version.py b/django/utils/version.py
index 18cd1387a0..a72d3202fa 100644
--- a/django/utils/version.py
+++ b/django/utils/version.py
@@ -89,8 +89,9 @@ def get_git_changeset():
         shell=True, cwd=repo_dir, universal_newlines=True,
     )
     timestamp = git_log.stdout
+    tz = datetime.timezone.utc
     try:
-        timestamp = datetime.datetime.utcfromtimestamp(int(timestamp))
+        timestamp = datetime.datetime.fromtimestamp(int(timestamp), tz=tz)
     except ValueError:
         return None
     return timestamp.strftime('%Y%m%d%H%M%S')