From f35ab74752adb37138112657c1bc8b91f50e799b Mon Sep 17 00:00:00 2001
From: Keryn Knight <keryn@kerynknight.com>
Date: Thu, 1 Jul 2021 12:05:41 +0100
Subject: [PATCH] Fixed #32892 -- Optimized django.utils.dateparse functions by
 using fromisoformat().

---
 django/utils/dateparse.py | 61 ++++++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/django/utils/dateparse.py b/django/utils/dateparse.py
index 47791b9331..60840933d5 100644
--- a/django/utils/dateparse.py
+++ b/django/utils/dateparse.py
@@ -72,10 +72,12 @@ def parse_date(value):
     Raise ValueError if the input is well formatted but not a valid date.
     Return None if the input isn't well formatted.
     """
-    match = date_re.match(value)
-    if match:
-        kw = {k: int(v) for k, v in match.groupdict().items()}
-        return datetime.date(**kw)
+    try:
+        return datetime.date.fromisoformat(value)
+    except ValueError:
+        if match := date_re.match(value):
+            kw = {k: int(v) for k, v in match.groupdict().items()}
+            return datetime.date(**kw)
 
 
 def parse_time(value):
@@ -87,12 +89,18 @@ def parse_time(value):
     Return None if the input isn't well formatted, in particular if it
     contains an offset.
     """
-    match = time_re.match(value)
-    if match:
-        kw = match.groupdict()
-        kw['microsecond'] = kw['microsecond'] and kw['microsecond'].ljust(6, '0')
-        kw = {k: int(v) for k, v in kw.items() if v is not None}
-        return datetime.time(**kw)
+    try:
+        # The fromisoformat() method takes time zone info into account and
+        # returns a time with a tzinfo component, if possible. However, there
+        # are no circumstances where aware datetime.time objects make sense, so
+        # remove the time zone offset.
+        return datetime.time.fromisoformat(value).replace(tzinfo=None)
+    except ValueError:
+        if match := time_re.match(value):
+            kw = match.groupdict()
+            kw['microsecond'] = kw['microsecond'] and kw['microsecond'].ljust(6, '0')
+            kw = {k: int(v) for k, v in kw.items() if v is not None}
+            return datetime.time(**kw)
 
 
 def parse_datetime(value):
@@ -104,22 +112,23 @@ def parse_datetime(value):
     Raise ValueError if the input is well formatted but not a valid datetime.
     Return None if the input isn't well formatted.
     """
-    match = datetime_re.match(value)
-    if match:
-        kw = match.groupdict()
-        kw['microsecond'] = kw['microsecond'] and kw['microsecond'].ljust(6, '0')
-        tzinfo = kw.pop('tzinfo')
-        if tzinfo == 'Z':
-            tzinfo = utc
-        elif tzinfo is not None:
-            offset_mins = int(tzinfo[-2:]) if len(tzinfo) > 3 else 0
-            offset = 60 * int(tzinfo[1:3]) + offset_mins
-            if tzinfo[0] == '-':
-                offset = -offset
-            tzinfo = get_fixed_timezone(offset)
-        kw = {k: int(v) for k, v in kw.items() if v is not None}
-        kw['tzinfo'] = tzinfo
-        return datetime.datetime(**kw)
+    try:
+        return datetime.datetime.fromisoformat(value)
+    except ValueError:
+        if match := datetime_re.match(value):
+            kw = match.groupdict()
+            kw['microsecond'] = kw['microsecond'] and kw['microsecond'].ljust(6, '0')
+            tzinfo = kw.pop('tzinfo')
+            if tzinfo == 'Z':
+                tzinfo = utc
+            elif tzinfo is not None:
+                offset_mins = int(tzinfo[-2:]) if len(tzinfo) > 3 else 0
+                offset = 60 * int(tzinfo[1:3]) + offset_mins
+                if tzinfo[0] == '-':
+                    offset = -offset
+                tzinfo = get_fixed_timezone(offset)
+            kw = {k: int(v) for k, v in kw.items() if v is not None}
+            return datetime.datetime(**kw, tzinfo=tzinfo)
 
 
 def parse_duration(value):