chore: deprecate TimezoneGMT class (#2302)

* chore: deprecate TimezoneGMT class

* chore: address review comments

docs/_newsfragments/2301.misc.rst

@@ -0,0 +1 @@
+Deprecated the ``TimezoneGMT`` class. Use :attr:`datetime.timezone.utc` instead.

falcon/response.py

@@ -16,6 +16,7 @@
 
 from __future__ import annotations
 
+from datetime import timezone
 import functools
 import mimetypes
 from typing import Dict, Optional
@@ -35,14 +36,11 @@
 from falcon.util import http_cookies
 from falcon.util import http_status_to_code
 from falcon.util import structures
-from falcon.util import TimezoneGMT
 from falcon.util.deprecation import AttributeRemovedError
 from falcon.util.deprecation import deprecated
 from falcon.util.uri import encode_check_escaped as uri_encode
 from falcon.util.uri import encode_value_check_escaped as uri_encode_value
 
-GMT_TIMEZONE = TimezoneGMT()
-
 _STREAM_LEN_REMOVED_MSG = (
     'The deprecated stream_len property was removed in Falcon 3.0. '
     'Please use Response.set_stream() or Response.content_length instead.'
@@ -503,7 +501,7 @@ def set_cookie(  # noqa: C901
                 self._cookies[name]['expires'] = expires.strftime(fmt)
             else:
                 # aware
-                gmt_expires = expires.astimezone(GMT_TIMEZONE)
+                gmt_expires = expires.astimezone(timezone.utc)
                 self._cookies[name]['expires'] = gmt_expires.strftime(fmt)
 
         if max_age:

falcon/util/time.py

@@ -12,6 +12,8 @@
 import datetime
 from typing import Optional
 
+from .deprecation import deprecated
+
 __all__ = ('TimezoneGMT',)
 
 
@@ -20,6 +22,10 @@ class TimezoneGMT(datetime.tzinfo):
 
     GMT_ZERO = datetime.timedelta(hours=0)
 
+    @deprecated('TimezoneGMT is deprecated, use datetime.timezone.utc instead')
+    def __init__(self) -> None:
+        super().__init__()
+
     def utcoffset(self, dt: Optional[datetime.datetime]) -> datetime.timedelta:
         """Get the offset from UTC.
 

tests/test_cookies.py

@@ -1,7 +1,6 @@
 from datetime import datetime
 from datetime import timedelta
 from datetime import timezone
-from datetime import tzinfo
 from http import cookies as http_cookies
 import re
 
@@ -10,25 +9,10 @@
 import falcon
 import falcon.testing as testing
 from falcon.util import http_date_to_dt
-from falcon.util import TimezoneGMT
 
 UNICODE_TEST_STRING = 'Unicode_\xc3\xa6\xc3\xb8'
 
 
-class TimezoneGMTPlus1(tzinfo):
-    def utcoffset(self, dt):
-        return timedelta(hours=1)
-
-    def tzname(self, dt):
-        return 'GMT+1'
-
-    def dst(self, dt):
-        return timedelta(hours=1)
-
-
-GMT_PLUS_ONE = TimezoneGMTPlus1()
-
-
 def utcnow_naive():
     return datetime.now(timezone.utc).replace(tzinfo=None)
 
@@ -49,7 +33,9 @@ def on_post(self, req, resp):
         resp.unset_cookie('bad')
 
     def on_put(self, req, resp):
-        e = datetime(year=2050, month=1, day=1, tzinfo=GMT_PLUS_ONE)  # aware
+        e = datetime(
+            year=2050, month=1, day=1, tzinfo=timezone(timedelta(hours=1))
+        )  # aware
         resp.set_cookie('foo', 'bar', http_only=False, secure=False, expires=e)
         resp.unset_cookie('bad')
 
@@ -289,7 +275,7 @@ def test_cookie_expires_aware(client):
     assert not cookie.secure
 
 
-def test_cookies_setable(client):
+def test_cookies_setable():
     resp = falcon.Response()
 
     assert resp._cookies is None
@@ -321,14 +307,14 @@ def test_cookie_max_age_float_and_string(client, cookie_name):
     assert not cookie.secure
 
 
-def test_response_unset_cookie(client):
+def test_response_unset_cookie():
     resp = falcon.Response()
     resp.unset_cookie('bad')
     resp.set_cookie('bad', 'cookie', max_age=300)
     resp.unset_cookie('bad')
 
     morsels = list(resp._cookies.values())
-    len(morsels) == 1
+    assert len(morsels) == 1
 
     bad_cookie = morsels[0]
     assert bad_cookie['expires'] == -1
@@ -343,11 +329,6 @@ def test_response_unset_cookie(client):
     assert expiration < utcnow_naive()
 
 
-def test_cookie_timezone(client):
-    tz = TimezoneGMT()
-    assert tz.tzname(timedelta(0)) == 'GMT'
-
-
 # =====================================================================
 # Request
 # =====================================================================

tests/test_utils.py

@@ -1,4 +1,5 @@
 from datetime import datetime
+from datetime import timedelta
 from datetime import timezone
 import functools
 import http
@@ -22,6 +23,7 @@
 from falcon.util import misc
 from falcon.util import structures
 from falcon.util import uri
+from falcon.util.time import TimezoneGMT
 
 try:
     import msgpack  # type: ignore
@@ -1419,3 +1421,13 @@ def test_json_deprecation():
 
     with pytest.raises(AttributeError):
         falcon.util.some_imaginary_module
+
+
+def test_TimezoneGMT():
+    with pytest.warns(deprecation.DeprecatedWarning):
+        tz = TimezoneGMT()
+
+    z = timedelta(0)
+    assert tz.tzname(None) == 'GMT'
+    assert tz.dst(None) == z
+    assert tz.utcoffset(None) == z