fix(ndb): replace deprecated datetime.utcnow() and utcfromtimestamp()

packages/google-cloud-ndb/google/cloud/ndb/model.py

@@ -352,6 +352,17 @@ class Person(Model):
 _getfullargspec = inspect.getfullargspec
 
 
+def _utcnow():
+    """Return the current UTC time as a naive :class:`~datetime.datetime`.
+
+    ``datetime.datetime.utcnow()`` is deprecated since Python 3.12 and
+    scheduled for removal. Its replacement, ``datetime.datetime.now(timezone.utc)``,
+    returns an offset-aware value, but ``ndb`` stores and compares naive
+    datetimes presumed to be UTC, so the offset is stripped again here.
+    """
+    return datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None)
+
+
 class KindError(exceptions.BadValueError):
     """Raised when an implementation for a kind can't be found.
 
@@ -2092,7 +2103,7 @@ def _legacy_db_get_value(v, p):
         # A custom 'meaning' for compressed properties.
         _MEANING_URI_COMPRESSED = "ZLIB"
         # The Epoch (a zero POSIX timestamp).
-        _EPOCH = datetime.datetime.utcfromtimestamp(0)
+        _EPOCH = datetime.datetime(1970, 1, 1)
         # This is awkward but there seems to be no faster way to inspect
         # what union member is present.  datastore_types.FromPropertyPb(),
         # the undisputed authority, has the same series of if-elif blocks.
@@ -3933,7 +3944,7 @@ def _now():
 
         Subclasses will override this to return different forms of "now".
         """
-        return datetime.datetime.utcnow()
+        return _utcnow()
 
     def _prepare_for_put(self, entity):
         """Sets the current timestamp when "auto" is set.
@@ -4055,7 +4066,7 @@ def _from_base_type(self, value):
     @staticmethod
     def _now():
         """datetime.datetime: Return current date."""
-        return datetime.datetime.utcnow().date()
+        return _utcnow().date()
 
 
 class TimeProperty(DateTimeProperty):
@@ -4124,7 +4135,7 @@ def _from_base_type(self, value):
     @staticmethod
     def _now():
         """datetime.datetime: Return current time."""
-        return datetime.datetime.utcnow().time()
+        return _utcnow().time()
 
 
 class StructuredProperty(Property):

packages/google-cloud-ndb/tests/system/test_crud.py

@@ -1411,7 +1411,7 @@ class SomeKind(ndb.Model):
     now = datetime.datetime.now(pytz.utc)
     entity = SomeKind(
         alarm1=now,
-        alarm2=datetime.datetime.utcnow(),  # naive
+        alarm2=now.replace(tzinfo=None),  # same instant, naive
     )
     key = entity.put()
     dispose_of(key._key)

packages/google-cloud-ndb/tests/unit/test_model.py

@@ -297,6 +297,17 @@ def test__fix_up():
         assert attr._fix_up(model.Model, "birthdate") is None
 
 
+def test__utcnow():
+    before = datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None)
+    value = model._utcnow()
+    after = datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None)
+
+    # ndb stores naive datetimes presumed to be UTC, so the helper must not
+    # leak the tzinfo that datetime.now(timezone.utc) attaches.
+    assert value.tzinfo is None
+    assert before <= value <= after
+
+
 class Test_BaseValue:
     @staticmethod
     def test_constructor():
@@ -2974,7 +2985,7 @@ def test_constructor_defaults():
 
     @staticmethod
     def test_constructor_explicit():
-        now = datetime.datetime.utcnow()
+        now = model._utcnow()
         prop = model.DateTimeProperty(
             name="dt_val",
             auto_now=True,
@@ -3014,7 +3025,7 @@ def test_constructor_repeated():
     @staticmethod
     def test__validate():
         prop = model.DateTimeProperty(name="dt_val")
-        value = datetime.datetime.utcnow()
+        value = model._utcnow()
         assert prop._validate(value) is None
 
     @staticmethod
@@ -3150,7 +3161,7 @@ class TestDateProperty:
     @staticmethod
     def test__validate():
         prop = model.DateProperty(name="d_val")
-        value = datetime.datetime.utcnow().date()
+        value = model._utcnow().date()
         assert prop._validate(value) is None
 
     @staticmethod
@@ -3186,7 +3197,7 @@ class TestTimeProperty:
     @staticmethod
     def test__validate():
         prop = model.TimeProperty(name="t_val")
-        value = datetime.datetime.utcnow().time()
+        value = model._utcnow().time()
         assert prop._validate(value) is None
 
     @staticmethod

packages/google-cloud-ndb/tests/unit/test_stats.py

@@ -21,7 +21,7 @@
 DEFAULTS = {
     "bytes": 4,
     "count": 2,
-    "timestamp": datetime.datetime.utcfromtimestamp(40),
+    "timestamp": datetime.datetime(1970, 1, 1, 0, 0, 40),
 }