Allow for timestamps before UNIX epoch (msgpack#433)

pohlt · web-flow · commit 5614dd5a8987 · 2020-07-23T17:53:55.000+09:00
diff --git a/msgpack/ext.py b/msgpack/ext.py
@@ -178,7 +178,9 @@ def to_datetime(self):
 
         :rtype: datetime.
         """
-        return datetime.datetime.fromtimestamp(self.to_unix(), _utc)
+        return datetime.datetime.fromtimestamp(0, _utc) + datetime.timedelta(
+            seconds=self.to_unix()
+        )
 
     @staticmethod
     def from_datetime(dt):
