ChilliCream · glen-84 · Jun 10, 2025 · Jun 10, 2025 · Jun 10, 2025 · Jun 10, 2025
diff --git a/dictionary.txt b/dictionary.txt
@@ -18,6 +18,7 @@ BCPROCKS
 bfnrt
 blazor
 blazorwasm
+Brontie
 Browsable
 BSON
 buildtransitive
@@ -109,7 +110,6 @@ NSwag
 ntouches
 nwithin
 oncall
-oneof
 OpenIddict
 opensgid
 OPTOUT

diff --git a/src/HotChocolate/Caching/test/Caching.Tests/SchemaTests.cs b/src/HotChocolate/Caching/test/Caching.Tests/SchemaTests.cs
@@ -49,13 +49,7 @@ enum CacheControlScope {
             "The `@cacheControl` directive may be provided for individual fields or entire object, interface or union types to provide caching hints to the executor."
             directive @cacheControl("The maximum amount of time this field's cached value is valid, in seconds." maxAge: Int "The maximum amount of time this field's cached value is valid in shared caches like CDNs, in seconds." sharedMaxAge: Int "If `true`, the field inherits the `maxAge` of its parent field." inheritMaxAge: Boolean "If `PRIVATE`, the field's value is specific to a single user. The default value is `PUBLIC`, which means the field's value is not tied to a single user." scope: CacheControlScope "The Vary HTTP response header describes the parts of the request message aside from the method and URL that influenced the content of the response it occurs in. Most often, this is used to create a cache key when content negotiation is in use." vary: [String]) on OBJECT | FIELD_DEFINITION | INTERFACE | UNION
 
-            """
-            The `@oneOf` directive is used within the type system definition language
-             to indicate:
-
-             - an Input Object is a Oneof Input Object, or
-             - an Object Type's Field is a Oneof Field.
-            """
+            "The `@oneOf` directive is used within the type system definition language to indicate an Input Object is a OneOf Input Object."
             directive @oneOf on INPUT_OBJECT
 
             """

diff --git a/src/HotChocolate/Core/src/Execution/Properties/Resources.Designer.cs b/src/HotChocolate/Core/src/Execution/Properties/Resources.Designer.cs
diff --git a/src/HotChocolate/Core/src/Execution/Properties/Resources.resx b/src/HotChocolate/Core/src/Execution/Properties/Resources.resx
@@ -277,7 +277,7 @@
     <value>The type {0} was already added.</value>
   </data>
   <data name="ThrowHelper_OneOfFieldMustBeNonNull" xml:space="preserve">
-    <value>Value for oneof field {0} must be non-null.</value>
+    <value>Value for OneOf field {0} must be non-null.</value>
   </data>
   <data name="ThrowHelper_Operation_NoSelectionSet" xml:space="preserve">
     <value>The specified selection does not have a selection set.</value>

diff --git a/src/HotChocolate/Core/src/Types.Shared/BuiltInTypes.cs b/src/HotChocolate/Core/src/Types.Shared/BuiltInTypes.cs
@@ -28,7 +28,8 @@ public static class BuiltInTypes
         WellKnownDirectives.Deprecated,
         WellKnownDirectives.Defer,
         WellKnownDirectives.Stream,
-        WellKnownDirectives.SpecifiedBy
+        WellKnownDirectives.SpecifiedBy,
+        WellKnownDirectives.OneOf
     ];
 
     public static bool IsBuiltInType(string name)

diff --git a/src/HotChocolate/Core/src/Types.Shared/WellKnownDirectives.cs b/src/HotChocolate/Core/src/Types.Shared/WellKnownDirectives.cs
@@ -9,4 +9,5 @@ internal static class WellKnownDirectives
     public const string Deprecated = "deprecated";
     public const string SpecifiedBy = "specifiedBy";
     public const string DeprecationReasonArgument = "reason";
+    public const string OneOf = "oneOf";
 }
diff --git a/src/HotChocolate/Core/src/Types/Properties/TypeResources.Designer.cs b/src/HotChocolate/Core/src/Types/Properties/TypeResources.Designer.cs
diff --git a/src/HotChocolate/Core/src/Types/Properties/TypeResources.resx b/src/HotChocolate/Core/src/Types/Properties/TypeResources.resx
@@ -700,20 +700,16 @@ Type: `{0}`</value>
     <value>The fieldName cannot be null or empty.</value>
   </data>
   <data name="OneOfDirectiveType_Description" xml:space="preserve">
-    <value>The `@oneOf` directive is used within the type system definition language
- to indicate:
-
- - an Input Object is a Oneof Input Object, or
- - an Object Type's Field is a Oneof Field.</value>
+    <value>The `@oneOf` directive is used within the type system definition language to indicate an Input Object is a OneOf Input Object.</value>
   </data>
   <data name="ThrowHelper_OneOfNoFieldSet" xml:space="preserve">
-    <value>The Oneof Input Objects `{0}` require that exactly one field must be supplied and that field must not be `null`. Oneof Input Objects are a special variant of Input Objects where the type system asserts that exactly one of the fields must be set and non-null.</value>
+    <value>The OneOf Input Objects `{0}` require that exactly one field must be supplied and that field must not be `null`. OneOf Input Objects are a special variant of Input Objects where the type system asserts that exactly one of the fields must be set and non-null.</value>
   </data>
   <data name="ThrowHelper_OneOfMoreThanOneFieldSet" xml:space="preserve">
-    <value>More than one field of the Oneof Input Object `{0}` is set. Oneof Input Objects are a special variant of Input Objects where the type system asserts that exactly one of the fields must be set and non-null.</value>
+    <value>More than one field of the OneOf Input Object `{0}` is set. OneOf Input Objects are a special variant of Input Objects where the type system asserts that exactly one of the fields must be set and non-null.</value>
   </data>
   <data name="ThrowHelper_OneOfFieldIsNull" xml:space="preserve">
-    <value>`null` was set to the field `{0}`of the Oneof Input Object `{1}`. Oneof Input Objects are a special variant of Input Objects where the type system asserts that exactly one of the fields must be set and non-null.</value>
+    <value>`null` was set to the field `{0}`of the OneOf Input Object `{1}`. OneOf Input Objects are a special variant of Input Objects where the type system asserts that exactly one of the fields must be set and non-null.</value>
   </data>
   <data name="ReflectionUtils_ExtractMethod_MethodExpected" xml:space="preserve">
     <value>Member is not a method!</value>
@@ -880,8 +876,8 @@ Type: `{0}`</value>
   <data name="ErrorHelper_ArgumentNotImplemented" xml:space="preserve">
     <value>The argument `{0}` of the implemented field `{1}` must be defined. The field `{2}` must include an argument of the same name for every argument defined on the implemented field of the interface type `{3}`.</value>
   </data>
-  <data name="ErrorHelper_OneofInputObjectMustHaveNullableFieldsWithoutDefaults" xml:space="preserve">
-    <value>Oneof Input Object `{0}` must only have nullable fields without default values. Edit your type and make the field{1} `{2}` nullable and remove any defaults.</value>
+  <data name="ErrorHelper_OneOfInputObjectMustHaveNullableFieldsWithoutDefaults" xml:space="preserve">
+    <value>OneOf Input Object `{0}` must only have nullable fields without default values. Edit your type and make the field{1} `{2}` nullable and remove any defaults.</value>
   </data>
   <data name="ErrorHelper_InputObjectMustNotHaveRecursiveNonNullableReferencesToSelf" xml:space="preserve">
     <value>Cannot reference Input Object `{0}` within itself through a series of non-null fields `{1}`.</value>

diff --git a/src/HotChocolate/Core/src/Types/Types/Directives/OneOfAttribute.cs b/src/HotChocolate/Core/src/Types/Types/Directives/OneOfAttribute.cs
@@ -4,7 +4,7 @@ namespace HotChocolate.Types;
 
 /// <summary>
 /// The `@oneOf` directive is used within the type system definition language
-/// to indicate an Input Object is a Oneof Input Object.
+/// to indicate an Input Object is a OneOf Input Object.
 ///
 /// <code>
 /// input UserUniqueCondition @oneOf {

diff --git a/src/HotChocolate/Core/src/Types/Types/Directives/OneOfDirectiveType.cs b/src/HotChocolate/Core/src/Types/Types/Directives/OneOfDirectiveType.cs
@@ -4,7 +4,7 @@ namespace HotChocolate.Types;
 
 /// <summary>
 /// The `@oneOf` directive is used within the type system definition language
-/// to indicate an Input Object is a Oneof Input Object.
+/// to indicate an Input Object is a OneOf Input Object.
 ///
 /// <code>
 /// input UserUniqueCondition @oneOf {

diff --git a/src/HotChocolate/Core/src/Types/Types/Extensions/InputObjectTypeDescriptorExtensions.cs b/src/HotChocolate/Core/src/Types/Types/Extensions/InputObjectTypeDescriptorExtensions.cs
@@ -40,7 +40,7 @@ public static IInputObjectTypeDescriptor<T> Ignore<T>(
     }
 
     /// <summary>
-    /// Defines an input object type as a oneof input object type
+    /// Defines an input object type as a OneOf input object type
     /// where only ever one field can hold a value.
     /// </summary>
     /// <param name="descriptor">
@@ -60,7 +60,7 @@ public static IInputObjectTypeDescriptor OneOf(this IInputObjectTypeDescriptor d
     }
 
     /// <summary>
-    /// Defines an input object type as a oneof input object type
+    /// Defines an input object type as a OneOf input object type
     /// where only ever one field can hold a value.
     /// </summary>
     /// <param name="descriptor">

diff --git a/src/HotChocolate/Core/src/Types/Types/Introspection/__Type.cs b/src/HotChocolate/Core/src/Types/Types/Introspection/__Type.cs
@@ -85,9 +85,9 @@ protected override ObjectTypeConfiguration CreateConfiguration(ITypeDiscoveryCon
 
         if (context.DescriptorContext.Options.EnableOneOf)
         {
-            def.Fields.Add(new(Names.OneOf,
+            def.Fields.Add(new(Names.IsOneOf,
                 type: booleanType,
-                pureResolver: Resolvers.OneOf));
+                pureResolver: Resolvers.IsOneOf));
         }
 
         if (context.DescriptorContext.Options.EnableDirectiveIntrospection)
@@ -160,7 +160,7 @@ public static object Kind(IResolverContext context)
                 _ => null
             };
 
-        public static object? OneOf(IResolverContext context)
+        public static object? IsOneOf(IResolverContext context)
             => context.Parent<IType>() is IInputObjectTypeDefinition iot
                 ? iot.Directives.ContainsName(DirectiveNames.OneOf.Name)
                 : null;
@@ -191,7 +191,7 @@ public static class Names
         public const string EnumValues = "enumValues";
         public const string InputFields = "inputFields";
         public const string OfType = "ofType";
-        public const string OneOf = "oneOf";
+        public const string IsOneOf = "isOneOf";
         public const string SpecifiedByUrl = "specifiedByURL";
         public const string IncludeDeprecated = "includeDeprecated";
         public const string AppliedDirectives = "appliedDirectives";

diff --git a/src/HotChocolate/Core/src/Types/Utilities/ErrorHelper.cs b/src/HotChocolate/Core/src/Types/Utilities/ErrorHelper.cs
@@ -183,7 +183,7 @@ public static ISchemaError OneOfInputObjectMustHaveNullableFieldsWithoutDefaults
         string[] fieldNames)
         => SchemaErrorBuilder.New()
             .SetMessage(
-                ErrorHelper_OneofInputObjectMustHaveNullableFieldsWithoutDefaults,
+                ErrorHelper_OneOfInputObjectMustHaveNullableFieldsWithoutDefaults,
                 type.Name,
                 fieldNames.Length is 1 ? string.Empty : "s",
                 string.Join(", ", fieldNames))

diff --git a/src/HotChocolate/Core/src/Validation/ErrorHelper.cs b/src/HotChocolate/Core/src/Validation/ErrorHelper.cs
@@ -649,7 +649,7 @@ public static IError OneOfMustHaveExactlyOneField(
             .AddLocation(node)
             .SetPath(context.CreateErrorPath())
             .SetExtension(nameof(type), type.Name)
-            .SpecifiedBy("sec-OneOf-Input-Objects-Have-Exactly-One-Field", rfc: 825)
+            .SpecifiedBy("sec-All-Variable-Usages-Are-Allowed", rfc: 825)
             .Build();
 
     public static IError OneOfVariablesMustBeNonNull(
@@ -666,7 +666,7 @@ public static IError OneOfVariablesMustBeNonNull(
             .AddLocation(node)
             .SetPath(context.CreateErrorPath())
             .SetFieldCoordinate(fieldCoordinate)
-            .SpecifiedBy("sec-Oneof–Input-Objects-Have-Exactly-One-Field", rfc: 825)
+            .SpecifiedBy("sec-All-Variable-Usages-Are-Allowed", rfc: 825)
             .Build();
 
     public static IError SkipAndIncludeNotAllowedOnSubscriptionRootField(

diff --git a/src/HotChocolate/Core/src/Validation/Properties/Resources.Designer.cs b/src/HotChocolate/Core/src/Validation/Properties/Resources.Designer.cs
diff --git a/src/HotChocolate/Core/src/Validation/Properties/Resources.resx b/src/HotChocolate/Core/src/Validation/Properties/Resources.resx
@@ -216,10 +216,10 @@
     <value>Introspection is not allowed for the current request.</value>
   </data>
   <data name="ErrorHelper_OneOfMustHaveExactlyOneField" xml:space="preserve">
-    <value>The Oneof Input Object `{0}` requires that exactly one field must be supplied and that field must not be `null`.</value>
+    <value>The OneOf Input Object `{0}` requires that exactly one field must be supplied and that field must not be `null`.</value>
   </data>
   <data name="ErrorHelper_OneOfVariablesMustBeNonNull" xml:space="preserve">
-    <value>The variable `${0}` assigned to the field `{1}` of the Oneof Input Object `{2}` must be non-null.</value>
+    <value>The variable `${0}` assigned to the field `{1}` of the OneOf Input Object `{2}` must be non-null.</value>
   </data>
   <data name="ErrorHelper_SkipAndIncludeNotAllowedOnSubscriptionRootField" xml:space="preserve">
     <value>The skip and include directives are not allowed to be used on root fields of the subscription type.</value>

diff --git a/src/HotChocolate/Core/src/Validation/Rules/ValueVisitor.cs b/src/HotChocolate/Core/src/Validation/Rules/ValueVisitor.cs
@@ -40,7 +40,7 @@ namespace HotChocolate.Validation.Rules;
 ///
 /// AND
 ///
-/// Oneof Input Objects require that exactly one field must be supplied and that
+/// OneOf Input Objects require that exactly one field must be supplied and that
 /// field must not be {null}.
 ///
 /// DRAFT: https://github.com/graphql/graphql-spec/pull/825

diff --git a/src/HotChocolate/Core/src/Validation/Rules/VariableVisitor.cs b/src/HotChocolate/Core/src/Validation/Rules/VariableVisitor.cs
@@ -250,7 +250,7 @@ protected override ISyntaxVisitorAction Enter(
         if (context.Variables.TryGetValue(
                 node.Name.Value,
                 out var variableDefinition)
-            && !IsVariableUsageAllowed(variableDefinition, context.Types.Peek(), defaultValue))
+            && !IsVariableUsageAllowed(variableDefinition, context, defaultValue))
         {
             context.ReportError(context.VariableIsNotCompatible(node, variableDefinition));
         }
@@ -281,10 +281,12 @@ protected override ISyntaxVisitorAction Leave(
     // http://facebook.github.io/graphql/June2018/#IsVariableUsageAllowed()
     private bool IsVariableUsageAllowed(
         VariableDefinitionNode variableDefinition,
-        IType locationType,
+        DocumentValidatorContext context,
         IValueNode? locationDefault)
     {
-        if (locationType.IsNonNullType()
+        var locationType = context.Types.Peek();
+
+        if (IsNonNullPosition(locationType, context)
             && !variableDefinition.Type.IsNonNullType())
         {
             if (variableDefinition.DefaultValue.IsNull()
@@ -303,6 +305,23 @@ private bool IsVariableUsageAllowed(
             locationType);
     }
 
+    private static bool IsNonNullPosition(IType locationType, DocumentValidatorContext context)
+    {
+        if (locationType.IsNonNullType())
+        {
+            return true;
+        }
+
+        if (context.Path.Peek() is ObjectFieldNode
+            && context.Types[^2].NullableType() is IInputObjectTypeDefinition inputObjectType
+            && inputObjectType.Directives.ContainsName(DirectiveNames.OneOf.Name))
+        {
+            return true;
+        }
+
+        return false;
+    }
+
     // http://facebook.github.io/graphql/June2018/#AreTypesCompatible()
     private bool AreTypesCompatible(
         ITypeNode variableType,

diff --git a/...WarsCodeFirst/__snapshots__/StarWarsCodeFirstTests.Ensure_Benchmark_Query_LargeQuery.snap b/...WarsCodeFirst/__snapshots__/StarWarsCodeFirstTests.Ensure_Benchmark_Query_LargeQuery.snap
@@ -5818,7 +5818,7 @@
               "deprecationReason": null
             },
             {
-              "name": "oneOf",
+              "name": "isOneOf",
               "description": null,
               "args": [],
               "type": {

diff --git a/...Core/test/Execution.Tests/__snapshots__/IntrospectionTests.DefaultValueIsInputObject.snap b/...Core/test/Execution.Tests/__snapshots__/IntrospectionTests.DefaultValueIsInputObject.snap
@@ -913,7 +913,7 @@
               "deprecationReason": null
             },
             {
-              "name": "oneOf",
+              "name": "isOneOf",
               "description": null,
               "args": [],
               "type": {

diff --git a/...t/Execution.Tests/__snapshots__/IntrospectionTests.ExecuteGraphiQLIntrospectionQuery.snap b/...t/Execution.Tests/__snapshots__/IntrospectionTests.ExecuteGraphiQLIntrospectionQuery.snap
@@ -913,7 +913,7 @@
               "deprecationReason": null
             },
             {
-              "name": "oneOf",
+              "name": "isOneOf",
               "description": null,
               "args": [],
               "type": {

diff --git a/...tion.Tests/__snapshots__/IntrospectionTests.ExecuteGraphiQLIntrospectionQuery_ToJson.snap b/...tion.Tests/__snapshots__/IntrospectionTests.ExecuteGraphiQLIntrospectionQuery_ToJson.snap
@@ -913,7 +913,7 @@
               "deprecationReason": null
             },
             {
-              "name": "oneOf",
+              "name": "isOneOf",
               "description": null,
               "args": [],
               "type": {