Add field repeated checks in vector search.

Author: WaVEV

django_mongodb_backend/indexes.py

@@ -185,7 +185,20 @@ def check(self, model, connection):
                         id=f"{self._error_id_prefix}.E004",
                     )
                 )
+        viewed = set()
         for field_name, _ in self.fields_orders:
+            if field_name in viewed:
+                errors.append(
+                    Error(
+                        f"Field '{field_name}' is defined more than once. Vector and filter"
+                        " fields must use distinct field names.",
+                        obj=self,
+                        hint="If you need different configurations for the same field,"
+                        " create separate indexes.",
+                        id=f"{self._error_id_prefix}.E005",
+                    )
+                )
+            viewed.add(field_name)
             field_ = model._meta.get_field(field_name)
             if isinstance(field_, ArrayField):
                 try:

tests/indexes_/test_checks.py

@@ -162,12 +162,14 @@ class Meta:
     @skipUnlessDBFeature("supports_atlas_search")
     def test_invalid_similarities_function(self):
         class Article(models.Model):
-            vector_data = ArrayField(models.DecimalField(), size=10)
+            vector1 = ArrayField(models.DecimalField(), size=10)
+            vector2 = ArrayField(models.DecimalField(), size=10)
+            vector3 = ArrayField(models.DecimalField(), size=10)
 
             class Meta:
                 indexes = [
                     VectorSearchIndex(
-                        fields=["vector_data", "vector_data", "vector_data"],
+                        fields=["vector1", "vector2", "vector3"],
                         similarities=["sum", "dotProduct", "tangh"],
                     ),
                 ]
@@ -191,6 +193,34 @@ class Meta:
             ],
         )
 
+    @skipUnlessDBFeature("supports_atlas_search")
+    def test_define_field_twice(self):
+        class Article(models.Model):
+            vector_data = ArrayField(models.DecimalField(), size=10)
+
+            class Meta:
+                indexes = [
+                    VectorSearchIndex(
+                        fields=["vector_data", "vector_data"],
+                        similarities="dotProduct",
+                    ),
+                ]
+
+        errors = checks.run_checks(app_configs=self.apps.get_app_configs(), databases={"default"})
+        self.assertEqual(
+            errors,
+            [
+                checks.Error(
+                    "Field 'vector_data' is defined more than once. Vector and filter"
+                    " fields must use distinct field names.",
+                    id="django_mongodb_backend.indexes.VectorSearchIndex.E005",
+                    hint="If you need different configurations for the same field,"
+                    " create separate indexes.",
+                    obj=Article._meta.indexes[0],
+                ),
+            ],
+        )
+
     @skipUnlessDBFeature("supports_atlas_search")
     def test_simple(self):
         class Article(models.Model):