From 6c86495bcee22eac19d7fb040b2988b830707cbd Mon Sep 17 00:00:00 2001
From: Nick Pope <nick@nickpope.me.uk>
Date: Wed, 12 Oct 2022 20:27:20 +0100
Subject: [PATCH] Simplified handling ambiguous/imaginary datetimes in
 django.utils.dateformat.

Instead of the separate property, we can just not set self.timezone if
the datetime is ambiguous or imaginary. This ensures that this check
will only ever happen once as it's dependant on the datetime object and
not the format string characters.
---
 django/utils/dateformat.py | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/django/utils/dateformat.py b/django/utils/dateformat.py
index 103bff7aae..f352c99f1a 100644
--- a/django/utils/dateformat.py
+++ b/django/utils/dateformat.py
@@ -56,20 +56,16 @@ class TimeFormat(Formatter):
         self.data = obj
         self.timezone = None
 
-        # We only support timezone when formatting datetime objects,
-        # not date objects (timezone information not appropriate),
-        # or time objects (against established django policy).
         if isinstance(obj, datetime):
+            # Timezone is only supported when formatting datetime objects, not
+            # date objects (timezone information not appropriate), or time
+            # objects (against established django policy).
             if is_naive(obj):
-                self.timezone = get_default_timezone()
+                timezone = get_default_timezone()
             else:
-                self.timezone = obj.tzinfo
-
-    @property
-    def _no_timezone_or_datetime_is_ambiguous_or_imaginary(self):
-        return not self.timezone or _datetime_ambiguous_or_imaginary(
-            self.data, self.timezone
-        )
+                timezone = obj.tzinfo
+            if not _datetime_ambiguous_or_imaginary(obj, timezone):
+                self.timezone = timezone
 
     def a(self):
         "'a.m.' or 'p.m.'"
@@ -136,7 +132,7 @@ class TimeFormat(Formatter):
 
         If timezone information is not available, return an empty string.
         """
-        if self._no_timezone_or_datetime_is_ambiguous_or_imaginary:
+        if self.timezone is None:
             return ""
 
         offset = self.timezone.utcoffset(self.data)
@@ -168,7 +164,7 @@ class TimeFormat(Formatter):
 
         If timezone information is not available, return an empty string.
         """
-        if self._no_timezone_or_datetime_is_ambiguous_or_imaginary:
+        if self.timezone is None:
             return ""
 
         return str(self.timezone.tzname(self.data))
@@ -185,7 +181,7 @@ class TimeFormat(Formatter):
 
         If timezone information is not available, return an empty string.
         """
-        if self._no_timezone_or_datetime_is_ambiguous_or_imaginary:
+        if self.timezone is None:
             return ""
 
         offset = self.timezone.utcoffset(self.data)
@@ -227,7 +223,7 @@ class DateFormat(TimeFormat):
 
     def I(self):  # NOQA: E743, E741
         "'1' if daylight saving time, '0' otherwise."
-        if self._no_timezone_or_datetime_is_ambiguous_or_imaginary:
+        if self.timezone is None:
             return ""
         return "1" if self.timezone.dst(self.data) else "0"