From 543996711d323722a1017e376619ae462a726ada Mon Sep 17 00:00:00 2001
From: Josh Thomas <josh@joshthomas.dev>
Date: Wed, 23 Apr 2025 04:03:14 -0500
Subject: [PATCH] Fix `UniqueTogetherValidator` to handle fields w/ `source`
 attr (#9688)

* Add failing test for `UniqueConstraint` validation with `source` attribute

* Fix `UniqueTogetherValidator` to handle fields with source attribute

* split inner sources logic out to tuple comprehension
---
 rest_framework/validators.py |  3 ++-
 tests/test_validators.py     | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/rest_framework/validators.py b/rest_framework/validators.py
index a152c6362..4c444cf01 100644
--- a/rest_framework/validators.py
+++ b/rest_framework/validators.py
@@ -188,7 +188,8 @@ class UniqueTogetherValidator:
                 if attrs[field_name] != getattr(serializer.instance, field_name)
             ]
 
-        condition_kwargs = {source: attrs[source] for source in self.condition_fields}
+        condition_sources = (serializer.fields[field_name].source for field_name in self.condition_fields)
+        condition_kwargs = {source: attrs[source] for source in condition_sources}
         if checked_values and None not in checked_values and qs_exists_with_condition(queryset, self.condition, condition_kwargs):
             field_names = ', '.join(self.fields)
             message = self.message.format(field_names=field_names)
diff --git a/tests/test_validators.py b/tests/test_validators.py
index 29b097ef3..d19734d98 100644
--- a/tests/test_validators.py
+++ b/tests/test_validators.py
@@ -683,6 +683,24 @@ class TestUniqueConstraintValidation(TestCase):
         result = serializer.save()
         self.assertIsInstance(result, UniqueConstraintNullableModel)
 
+    def test_unique_constraint_source(self):
+        class SourceUniqueConstraintSerializer(serializers.ModelSerializer):
+            raceName = serializers.CharField(source="race_name")
+
+            class Meta:
+                model = UniqueConstraintModel
+                fields = ("raceName", "position", "global_id", "fancy_conditions")
+
+        serializer = SourceUniqueConstraintSerializer(
+            data={
+                "raceName": "example",
+                "position": 5,
+                "global_id": 11,
+                "fancy_conditions": 11,
+            }
+        )
+        assert serializer.is_valid()
+
 
 # Tests for `UniqueForDateValidator`
 # ----------------------------------