docs(http_date_to_dt): document the scope of timezone-aware date changes

docs/changes/4.0.0.rst

@@ -226,7 +226,13 @@ Breaking Changes
   :class:`~falcon.HTTPStatus` classes were removed. (`#2090 <https://github.com/falconry/falcon/issues/2090>`__)
 - The function :func:`falcon.http_date_to_dt` now validates HTTP dates to have
   the correct timezone set. It now also returns timezone-aware
-  :class:`~datetime.datetime` objects. (`#2182 <https://github.com/falconry/falcon/issues/2182>`__)
+  :class:`~datetime.datetime` objects. As a consequence of this change, the
+  return value of :meth:`falcon.Request.get_header_as_datetime` (including the
+  derived properties :attr:`~falcon.Request.date`,
+  :attr:`~falcon.Request.if_modified_since`,
+  :attr:`~falcon.Request.if_unmodified_since`, and
+  :attr:`falcon.testing.Cookie.expires`) has also changed to timezone-aware.
+  (`#2182 <https://github.com/falconry/falcon/issues/2182>`__)
 - ``setup.cfg`` was dropped in favor of consolidating all static project
   configuration in ``pyproject.toml`` (``setup.py`` is still needed for
   programmatic control of the build process). While this change should not impact

falcon/request.py

@@ -472,6 +472,10 @@ def date(self) -> Optional[datetime]:
         """Value of the Date header, converted to a ``datetime`` instance.
 
         The header value is assumed to conform to RFC 1123.
+
+        .. versionchanged:: 4.0
+            This property now returns timezone-aware
+            :class:`~datetime.datetime` objects (or ``None``).
         """
         return self.get_header_as_datetime('Date')
 
@@ -525,6 +529,10 @@ def if_modified_since(self) -> Optional[datetime]:
         """Value of the If-Modified-Since header.
 
         Returns ``None`` if the header is missing.
+
+        .. versionchanged:: 4.0
+            This property now returns timezone-aware
+            :class:`~datetime.datetime` objects (or ``None``).
         """
         return self.get_header_as_datetime('If-Modified-Since')
 
@@ -533,6 +541,10 @@ def if_unmodified_since(self) -> Optional[datetime]:
         """Value of the If-Unmodified-Since header.
 
         Returns ``None`` if the header is missing.
+
+        .. versionchanged:: 4.0
+            This property now returns timezone-aware
+            :class:`~datetime.datetime` objects (or ``None``).
         """
         return self.get_header_as_datetime('If-Unmodified-Since')
 
@@ -1331,6 +1343,10 @@ def get_header_as_datetime(
             HTTPBadRequest: The header was not found in the request, but
                 it was required.
             HttpInvalidHeader: The header contained a malformed/invalid value.
+
+        .. versionchanged:: 4.0
+            This method now returns timezone-aware :class:`~datetime.datetime`
+            objects.
         """
 
         http_date = self.get_header(header, required=required)

falcon/testing/client.py

@@ -151,7 +151,12 @@ def value(self) -> str:
 
     @property
     def expires(self) -> Optional[dt.datetime]:
-        """Expiration timestamp for the cookie, or ``None`` if not specified."""
+        """Expiration timestamp for the cookie, or ``None`` if not specified.
+
+        .. versionchanged:: 4.0
+            This property now returns timezone-aware
+            :class:`~datetime.datetime` objects (or ``None``).
+        """
         if self._expires:
             return http_date_to_dt(self._expires, obs_date=True)
 

falcon/util/misc.py

@@ -174,6 +174,10 @@ def http_date_to_dt(http_date: str, obs_date: bool = False) -> datetime.datetime
     Raises:
         ValueError: http_date doesn't match any of the available time formats
         ValueError: http_date doesn't match allowed timezones
+
+    .. versionchanged:: 4.0
+        This function now returns timezone-aware :class:`~datetime.datetime`
+        objects.
     """
     if not obs_date:
         # PERF(kgriffs): This violates DRY, but we do it anyway