[pull] main from django:main

django/contrib/sites/checks.py

@@ -1,14 +1,30 @@
-from types import NoneType
-
 from django.conf import settings
 from django.core.checks import Error
+from django.core.exceptions import ValidationError
 
 
 def check_site_id(app_configs, **kwargs):
-    if hasattr(settings, "SITE_ID") and not isinstance(
-        settings.SITE_ID, (NoneType, int)
-    ):
-        return [
-            Error("The SITE_ID setting must be an integer", id="sites.E101"),
-        ]
+    # Inner import avoids AppRegistryNotReady
+    from django.contrib.sites.models import Site
+
+    if hasattr(settings, "SITE_ID"):
+        try:
+            site_id = Site._meta.pk.to_python(settings.SITE_ID)
+        except ValidationError as exc:
+            return [
+                Error(
+                    f"The SITE_ID setting failed to validate: {exc}.", id="sites.E101"
+                ),
+            ]
+        else:
+            # to_python() might coerce a SITE_ID of the wrong type to the valid
+            # type, e.g. "1" to 1 for AutoField.
+            if site_id != settings.SITE_ID:
+                expected_type = type(site_id).__name__
+                return [
+                    Error(
+                        f"The SITE_ID setting must be of type {expected_type}.",
+                        id="sites.E101",
+                    ),
+                ]
     return []

django/core/serializers/pyyaml.py

@@ -23,37 +23,34 @@
 
 
 class DjangoSafeDumper(SafeDumper):
+    # The "safe" serializer is used for better interoperability.
+
     def represent_decimal(self, data):
         return self.represent_scalar("tag:yaml.org,2002:str", str(data))
 
     def represent_ordered_dict(self, data):
         return self.represent_mapping("tag:yaml.org,2002:map", data.items())
 
+    def represent_time(self, data):
+        # Base YAML doesn't support serialization of time types (as opposed to
+        # dates or datetimes, which it does support). Converting them to
+        # strings isn't perfect, but it's better than a "!!python/time" type
+        # which would prevent deserialization under any other language.
+        return self.represent_scalar("tag:yaml.org,2002:str", str(data))
+
 
 DjangoSafeDumper.add_representer(decimal.Decimal, DjangoSafeDumper.represent_decimal)
 DjangoSafeDumper.add_representer(
     collections.OrderedDict, DjangoSafeDumper.represent_ordered_dict
 )
+DjangoSafeDumper.add_representer(datetime.time, DjangoSafeDumper.represent_time)
 
 
 class Serializer(PythonSerializer):
     """Convert a queryset to YAML."""
 
     internal_use_only = False
 
-    def _value_from_field(self, obj, field):
-        # A nasty special case: base YAML doesn't support serialization of time
-        # types (as opposed to dates or datetimes, which it does support).
-        # Since we want to use the "safe" serializer for better
-        # interoperability, we need to do something with those pesky times.
-        # Converting 'em to strings isn't perfect, but it's better than a
-        # "!!python/time" type which would halt deserialization under any other
-        # language.
-        value = super()._value_from_field(obj, field)
-        if isinstance(value, datetime.time):
-            value = str(value)
-        return value
-
     def end_serialization(self):
         self.options.setdefault("allow_unicode", True)
         yaml.dump(

docs/ref/checks.txt

@@ -967,7 +967,8 @@ The following checks are performed on any model using a
 The following checks verify that :mod:`django.contrib.sites` is correctly
 configured:
 
-* **sites.E101**: The :setting:`SITE_ID` setting must be an integer.
+* **sites.E101**: The :setting:`SITE_ID` setting must be of type ``<type>``.
+  *or* The :setting:`SITE_ID` setting failed to validate: ``<error>``.
 
 ``staticfiles``
 ---------------

tests/sites_tests/tests.py

@@ -204,12 +204,25 @@ def test_site_natural_key(self):
         self.assertEqual(self.site.natural_key(), (self.site.domain,))
 
     @override_settings(SITE_ID="1")
-    def test_check_site_id(self):
+    def test_check_site_id_incorrect_type(self):
         self.assertEqual(
             check_site_id(None),
             [
                 checks.Error(
-                    msg="The SITE_ID setting must be an integer",
+                    msg="The SITE_ID setting must be of type int.",
+                    id="sites.E101",
+                ),
+            ],
+        )
+
+    @override_settings(SITE_ID="x")
+    def test_check_site_id_failed_to_validate(self):
+        self.assertEqual(
+            check_site_id(None),
+            [
+                checks.Error(
+                    msg="The SITE_ID setting failed to validate: ['“x” value "
+                    "must be an integer.'].",
                     id="sites.E101",
                 ),
             ],