[Backport 8.x] Fixed deserialization of datetime.date fields

elasticsearch_dsl/field.py

@@ -315,6 +315,9 @@ def _deserialize(self, data: Any) -> Union[datetime, date]:
                 raise ValidationException(
                     f"Could not parse date from the value ({data!r})", e
                 )
+            # we treat the yyyy-MM-dd format as a special case
+            if hasattr(self, "format") and self.format == "yyyy-MM-dd":
+                data = data.date()
 
         if isinstance(data, datetime):
             if self._default_timezone and data.tzinfo is None:

tests/test_field.py

@@ -17,7 +17,7 @@
 
 import base64
 import ipaddress
-from datetime import datetime
+from datetime import date, datetime, time
 from typing import cast
 
 import pytest
@@ -48,6 +48,24 @@ def test_boolean_deserialization() -> None:
     assert bf.deserialize(1)
 
 
+def test_datetime_deserialization() -> None:
+    f = field.Date()
+    dt = datetime.now()
+    assert dt == f._deserialize(dt.isoformat())
+
+    d = date.today()
+    assert datetime.combine(d, time()) == f._deserialize(d.isoformat())
+
+
+def test_date_deserialization() -> None:
+    f = field.Date(format="yyyy-MM-dd")
+    d = date.today()
+    assert d == f._deserialize(d.isoformat())
+
+    dt = datetime.now()
+    assert dt.date() == f._deserialize(dt.isoformat())
+
+
 def test_date_field_can_have_default_tz() -> None:
     f = field.Date(default_timezone="UTC")
     now = datetime.now()