Fix timezone handling for datetime to unixtime conversions (#2213)

* Fix timezone handling for datetime to unixtime conversions

datetime objects are supported to set expire, these can have timezones.
mktime was used to convert these to unixtime. mktime in Python however is not timezone aware, it expects the input to be UTC and redis-py did not convert the datetime timestamps to UTC before calling mktime.

This can lead to:
1) Setting incorrect expire times because the input datetime object has a timezone but is passed to mktime without converting to UTC first.
2) When the datetime timestamp is within DST, mktime fails with "OverflowError: mktime argument out of range" because UTC doesn't have DST. This depends on libc versions.

* linters

Co-authored-by: dvora-h <67596500+dvora-h@users.noreply.github.com>

2 files changed, 6 insertions, 7 deletions

diff --git a/tests/test_asyncio/test_commands.py b/tests/test_asyncio/test_commands.py
index eaae185..4c25277 100644
--- a/tests/test_asyncio/test_commands.py
+++ b/tests/test_asyncio/test_commands.py
@@ -4,7 +4,6 @@ Tests async overrides of commands from their mixins
 import binascii
 import datetime
 import re
-import time
 from string import ascii_letters
 
 import pytest
@@ -750,7 +749,7 @@ class TestRedisCommands:
     async def test_expireat_unixtime(self, r: redis.Redis):
         expire_at = await redis_server_time(r) + datetime.timedelta(minutes=1)
         await r.set("a", "foo")
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
+        expire_at_seconds = int(expire_at.timestamp())
         assert await r.expireat("a", expire_at_seconds)
         assert 0 < await r.ttl("a") <= 61
 
@@ -875,8 +874,8 @@ class TestRedisCommands:
     async def test_pexpireat_unixtime(self, r: redis.Redis):
         expire_at = await redis_server_time(r) + datetime.timedelta(minutes=1)
         await r.set("a", "foo")
-        expire_at_seconds = int(time.mktime(expire_at.timetuple())) * 1000
-        assert await r.pexpireat("a", expire_at_seconds)
+        expire_at_milliseconds = int(expire_at.timestamp() * 1000)
+        assert await r.pexpireat("a", expire_at_milliseconds)
         assert 0 < await r.pttl("a") <= 61000
 
     @skip_if_server_version_lt("2.6.0")
diff --git a/tests/test_commands.py b/tests/test_commands.py
index 715d18c..f9134d8 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -1185,7 +1185,7 @@ class TestRedisCommands:
     def test_expireat_unixtime(self, r):
         expire_at = redis_server_time(r) + datetime.timedelta(minutes=1)
         r["a"] = "foo"
-        expire_at_seconds = int(time.mktime(expire_at.timetuple()))
+        expire_at_seconds = int(expire_at.timestamp())
         assert r.expireat("a", expire_at_seconds) is True
         assert 0 < r.ttl("a") <= 61
 
@@ -1428,8 +1428,8 @@ class TestRedisCommands:
     def test_pexpireat_unixtime(self, r):
         expire_at = redis_server_time(r) + datetime.timedelta(minutes=1)
         r["a"] = "foo"
-        expire_at_seconds = int(time.mktime(expire_at.timetuple())) * 1000
-        assert r.pexpireat("a", expire_at_seconds) is True
+        expire_at_milliseconds = int(expire_at.timestamp() * 1000)
+        assert r.pexpireat("a", expire_at_milliseconds) is True
         assert 0 < r.pttl("a") <= 61000
 
     @skip_if_server_version_lt("7.0.0")