Fixed #36580 -- Fixed constraint validation crash when condition uses a ForeignObject.

Follow-up to e44e8327d3d88d86895735c0e427102063ff5b55. Refs #36222.

django/db/models/base.py

@@ -1357,7 +1357,7 @@ class Model(AltersData, metaclass=ModelBase):
         meta = meta or self._meta
         field_map = {}
         generated_fields = []
-        for field in meta.local_concrete_fields:
+        for field in meta.local_fields:
             if field.name in exclude:
                 continue
             if field.generated:
@@ -1368,7 +1368,19 @@ class Model(AltersData, metaclass=ModelBase):
                     continue
                 generated_fields.append(field)
                 continue
-            value = getattr(self, field.attname)
+            if (
+                isinstance(field.remote_field, ForeignObjectRel)
+                and field not in meta.local_concrete_fields
+            ):
+                value = tuple(
+                    getattr(self, from_field) for from_field in field.from_fields
+                )
+                if len(value) == 1:
+                    value = value[0]
+            elif field.concrete:
+                value = getattr(self, field.attname)
+            else:
+                continue
             if not value or not hasattr(value, "resolve_expression"):
                 value = Value(value, field)
             field_map[field.name] = value

tests/foreign_object/tests.py

@@ -3,10 +3,10 @@ import datetime
 import pickle
 from operator import attrgetter
 
-from django.core.exceptions import FieldError
+from django.core.exceptions import FieldError, ValidationError
 from django.db import connection, models
 from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature
-from django.test.utils import isolate_apps
+from django.test.utils import CaptureQueriesContext, isolate_apps
 from django.utils import translation
 
 from .models import (
@@ -771,7 +771,30 @@ class TestCachedPathInfo(TestCase):
 
 
 class ForeignObjectModelValidationTests(TestCase):
+    @skipUnlessDBFeature("supports_table_check_constraints")
+    def test_validate_constraints_with_foreign_object(self):
+        customer_tab = CustomerTab(customer_id=1500)
+        with self.assertRaisesMessage(ValidationError, "customer_id_limit"):
+            customer_tab.validate_constraints()
+
+    @skipUnlessDBFeature("supports_table_check_constraints")
+    def test_validate_constraints_success_case_single_query(self):
+        customer_tab = CustomerTab(customer_id=500)
+        with CaptureQueriesContext(connection) as ctx:
+            customer_tab.validate_constraints()
+        select_queries = [
+            query["sql"]
+            for query in ctx.captured_queries
+            if "select" in query["sql"].lower()
+        ]
+        self.assertEqual(len(select_queries), 1)
+
     @skipUnlessDBFeature("supports_table_check_constraints")
     def test_validate_constraints_excluding_foreign_object(self):
         customer_tab = CustomerTab(customer_id=150)
         customer_tab.validate_constraints(exclude={"customer"})
+
+    @skipUnlessDBFeature("supports_table_check_constraints")
+    def test_validate_constraints_excluding_foreign_object_member(self):
+        customer_tab = CustomerTab(customer_id=150)
+        customer_tab.validate_constraints(exclude={"customer_id"})