Introduce IResolveFieldContext.Parent (#2295)

docs2/site/docs/migrations/migration4.md

@@ -338,3 +338,4 @@ lock (field)
 * `ExecutionNode.PropagateNull` must be called before `ExecutionNode.ToValue`; see reference implementation
 * `IDocumentValidator.ValidateAsync` does not take `originalQuery` parameter; use `Document.OriginalQuery` instead
 * `IDocumentValidator.ValidateAsync` now returns `(IValidationResult validationResult, Variables variables)` tuple instead of single `IValidationResult` before
+* `IResolveFieldContext.FieldName` and `IResolveFieldContext.ReturnType` properties have been removed, use `IResolveFieldContext.FieldAst.Name` and `IResolveFieldContext.FieldDefinition.ResolvedType` instead

src/GraphQL.ApiTests/GraphQL.approved.txt

@@ -215,6 +215,7 @@ namespace GraphQL
         GraphQL.Language.AST.Fragments Fragments { get; }
         GraphQL.Instrumentation.Metrics Metrics { get; }
         GraphQL.Language.AST.Operation Operation { get; }
+        GraphQL.IResolveFieldContext Parent { get; }
         GraphQL.Types.IObjectGraphType ParentType { get; }
         System.Collections.Generic.IEnumerable<object> Path { get; }
         System.IServiceProvider RequestServices { get; }
@@ -289,6 +290,7 @@ namespace GraphQL
         public GraphQL.Language.AST.Fragments Fragments { get; }
         public GraphQL.Instrumentation.Metrics Metrics { get; }
         public GraphQL.Language.AST.Operation Operation { get; }
+        public GraphQL.IResolveFieldContext Parent { get; }
         public GraphQL.Types.IObjectGraphType ParentType { get; }
         public System.Collections.Generic.IEnumerable<object> Path { get; }
         public System.IServiceProvider RequestServices { get; }
@@ -315,6 +317,7 @@ namespace GraphQL
         public GraphQL.Language.AST.Fragments Fragments { get; set; }
         public GraphQL.Instrumentation.Metrics Metrics { get; set; }
         public GraphQL.Language.AST.Operation Operation { get; set; }
+        public GraphQL.IResolveFieldContext Parent { get; set; }
         public GraphQL.Types.IObjectGraphType ParentType { get; set; }
         public System.Collections.Generic.IEnumerable<object> Path { get; set; }
         public System.IServiceProvider RequestServices { get; set; }

src/GraphQL.MicrosoftDI/ScopedResolveFieldContextAdapter.cs

@@ -43,6 +43,8 @@ public ScopedResolveFieldContextAdapter(IResolveFieldContext baseContext, IServi
 
         public IObjectGraphType ParentType => _baseContext.ParentType;
 
+        public IResolveFieldContext Parent => _baseContext.Parent;
+
         public IDictionary<string, ArgumentValue> Arguments => _baseContext.Arguments;
 
         public object RootValue => _baseContext.RootValue;

src/GraphQL.Tests/Bugs/Issue899.cs

@@ -0,0 +1,109 @@
+using GraphQL.Types;
+using Shouldly;
+using Xunit;
+
+namespace GraphQL.Tests.Bugs
+{
+    public class Issue899 : QueryTestBase<Issue899Schema>
+    {
+        [Fact]
+        public void Issue899_Should_Work()
+        {
+            var query = @"
+query {
+  level1(arg1: ""1"") {
+    level2(arg2: ""2"") {
+      level3(arg3: ""3"") {
+        level4(arg4: ""4"")
+      }
+    }
+  }
+}
+";
+            var expected = @"{
+  ""level1"": {
+    ""level2"": [[{
+      ""level3"": [{
+        ""level4"": ""X""
+      }]
+    }]]
+  }
+}";
+            AssertQuerySuccess(query, expected, null);
+        }
+    }
+
+    public class Issue899Schema : Schema
+    {
+        public Issue899Schema()
+        {
+            Query = new Issue899Query();
+        }
+    }
+
+    public class Issue899Query : ObjectGraphType
+    {
+        public Issue899Query()
+        {
+            Field<Issue899Level1>("level1", resolve: context =>
+            {
+                context.GetArgument<string>("arg1").ShouldBe("1");
+                context.Parent.ShouldBeNull();
+
+                return new object();
+            },
+            arguments: new QueryArguments(new QueryArgument<StringGraphType> { Name = "arg1" }));
+        }
+    }
+
+    public class Issue899Level1 : ObjectGraphType
+    {
+        public Issue899Level1()
+        {
+            Field<ListGraphType<ListGraphType<Issue899Level2>>>("level2", resolve: context =>
+            {
+                context.GetArgument<string>("arg2").ShouldBe("2");
+                context.Parent.GetArgument<string>("arg1").ShouldBe("1");
+                context.Parent.Parent.ShouldBeNull();
+
+                return new[] { new[] { new object() } };
+            },
+            arguments: new QueryArguments(new QueryArgument<StringGraphType> { Name = "arg2" }));
+        }
+    }
+
+    public class Issue899Level2 : ObjectGraphType
+    {
+        public Issue899Level2()
+        {
+            Field<ListGraphType<Issue899Level3>>("level3", resolve: context =>
+            {
+                context.GetArgument<string>("arg3").ShouldBe("3");
+                context.Parent.GetArgument<string>("arg2").ShouldBe("2");
+                context.Parent.Parent.GetArgument<string>("arg1").ShouldBe("1");
+                context.Parent.Parent.Parent.ShouldBeNull();
+
+                return new[] { new object() };
+            },
+            arguments: new QueryArguments(new QueryArgument<StringGraphType> { Name = "arg3" }));
+        }
+    }
+
+    public class Issue899Level3 : ObjectGraphType
+    {
+        public Issue899Level3()
+        {
+            Field<StringGraphType>("level4", resolve: context =>
+            {
+                context.GetArgument<string>("arg4").ShouldBe("4");
+                context.Parent.GetArgument<string>("arg3").ShouldBe("3");
+                context.Parent.Parent.GetArgument<string>("arg2").ShouldBe("2");
+                context.Parent.Parent.Parent.GetArgument<string>("arg1").ShouldBe("1");
+                context.Parent.Parent.Parent.Parent.ShouldBeNull();
+
+                return "X";
+            },
+            arguments: new QueryArguments(new QueryArgument<StringGraphType> { Name = "arg4" }));
+        }
+    }
+}

src/GraphQL/ResolveFieldContext/IResolveFieldContext.cs

@@ -28,10 +28,16 @@ public interface IResolveFieldContext : IProvideUserContext
         /// <summary>The field's parent graph type.</summary>
         IObjectGraphType ParentType { get; }
 
+        /// <summary>
+        /// Provides access to the parent context (up to the root). This may be needed to get the parameters of parent nodes.
+        /// Returns <see langword="null"/> when called on the root.
+        /// </summary>
+        IResolveFieldContext Parent { get; }
+
         /// <summary>
         /// A dictionary of arguments passed to the field. It is recommended to use the
-        /// <see cref="GraphQL.ResolveFieldContextExtensions.GetArgument{TType}(IResolveFieldContext, string, TType)">GetArgument</see>
-        /// and <see cref="GraphQL.ResolveFieldContextExtensions.HasArgument(IResolveFieldContext, string)">HasArgument</see> extension
+        /// <see cref="ResolveFieldContextExtensions.GetArgument{TType}(IResolveFieldContext, string, TType)">GetArgument</see>
+        /// and <see cref="ResolveFieldContextExtensions.HasArgument(IResolveFieldContext, string)">HasArgument</see> extension
         /// methods rather than this dictionary, so the names can be converted by the selected <see cref="INameConverter"/>.
         /// </summary>
         IDictionary<string, ArgumentValue> Arguments { get; }

src/GraphQL/ResolveFieldContext/ReadonlyResolveFieldContext.cs

@@ -13,10 +13,12 @@ namespace GraphQL
     /// </summary>
     public class ReadonlyResolveFieldContext : IResolveFieldContext<object>
     {
+        // WARNING: if you add a new field here, then don't forget to clear it in Reset method!
         private ExecutionNode _executionNode;
         private ExecutionContext _executionContext;
         private IDictionary<string, ArgumentValue> _arguments;
         private Fields _subFields;
+        private IResolveFieldContext _parent;
 
         /// <summary>
         /// Initializes an instance with the specified <see cref="ExecutionNode"/> and <see cref="ExecutionContext"/>.
@@ -33,6 +35,8 @@ internal ReadonlyResolveFieldContext Reset(ExecutionNode node, ExecutionContext
             _executionContext = context;
             _arguments = null;
             _subFields = null;
+            _parent = null;
+
             return this;
         }
 
@@ -58,6 +62,25 @@ private Fields GetSubFields()
         /// <inheritdoc/>
         public IObjectGraphType ParentType => _executionNode.GetParentType(_executionContext.Schema);
 
+        /// <inheritdoc/>
+        public IResolveFieldContext Parent
+        {
+            get
+            {
+                if (_parent == null)
+                {
+                    var parent = _executionNode.Parent;
+                    while (parent is ArrayExecutionNode)
+                        parent = parent.Parent;
+
+                    if (parent != null && !(parent is RootExecutionNode))
+                        _parent = new ReadonlyResolveFieldContext(parent, _executionContext);
+                }
+
+                return _parent;
+            }
+        }
+
         /// <inheritdoc/>
         public IDictionary<string, ArgumentValue> Arguments => _arguments ??= GetArguments();
 

src/GraphQL/ResolveFieldContext/ResolveFieldContext.cs

@@ -23,6 +23,9 @@ public class ResolveFieldContext : IResolveFieldContext<object>
         /// <inheritdoc/>
         public IObjectGraphType ParentType { get; set; }
 
+        /// <inheritdoc/>
+        public IResolveFieldContext Parent { get; set; }
+
         /// <inheritdoc/>
         public IDictionary<string, ArgumentValue> Arguments { get; set; }
 
@@ -91,6 +94,7 @@ public ResolveFieldContext(IResolveFieldContext context)
             FieldAst = context.FieldAst;
             FieldDefinition = context.FieldDefinition;
             ParentType = context.ParentType;
+            Parent = context.Parent;
             Arguments = context.Arguments;
             Schema = context.Schema;
             Document = context.Document;

src/GraphQL/ResolveFieldContext/ResolveFieldContextAdapter.cs

@@ -59,6 +59,8 @@ internal ResolveFieldContextAdapter<T> Set(IResolveFieldContext baseContext)
 
         public IObjectGraphType ParentType => _baseContext.ParentType;
 
+        public IResolveFieldContext Parent => _baseContext.Parent;
+
         public IDictionary<string, ArgumentValue> Arguments => _baseContext.Arguments;
 
         public object RootValue => _baseContext.RootValue;

src/GraphQL/Types/Composite/IAbstractGraphType.cs

@@ -3,7 +3,7 @@
 namespace GraphQL.Types
 {
     /// <summary>
-    /// An interface for such graph types that do not represent concrete graph types, that is, for interfaces and unions. 
+    /// An interface for such graph types that do not represent concrete graph types, that is, for interfaces and unions.
     /// </summary>
     public interface IAbstractGraphType : IGraphType
     {
@@ -42,7 +42,7 @@ public static IObjectGraphType GetObjectType(this IAbstractGraphType abstractTyp
             return result;
         }
 
-        public static IObjectGraphType GetTypeOf(this IAbstractGraphType abstractType, object value)
+        public static IObjectGraphType GetTypeOf(this IAbstractGraphType abstractType, object value) //TODO: possible merge this into method above
         {
             foreach (var possible in abstractType.PossibleTypes.List)
             {