inline fragments now conditionally return correct field if on the rig…

…ht type and default value on other types
bzbetty · Jun 14, 2022 · Jun 14, 2022 · Jun 15, 2022 · Jun 14, 2022 · fbfd874257ee57d67e695437dd53a617814e82e0
commit fbfd874257ee57d67e695437dd53a617814e82e0
diff --git a/src/EntityGraphQL/Compiler/EntityGraphQLQueryWalker.cs b/src/EntityGraphQL/Compiler/EntityGraphQLQueryWalker.cs
@@ -147,7 +147,7 @@ protected override void VisitField(FieldNode node, IGraphQLNode? context)
                 throw new EntityGraphQLCompilerException("context should not be null visiting field");
             if (context.NextFieldContext == null)
                 throw new EntityGraphQLCompilerException("context.NextFieldContext should not be null visiting field");
-            
+
             var schemaType = schemaProvider.GetSchemaType(context.NextFieldContext.Type, requestContext);
             var actualField = schemaType.GetField(node.Name.Value, requestContext);
 
@@ -354,22 +354,37 @@ protected override void VisitFragmentDefinition(FragmentDefinitionNode node, IGr
 
         protected override void VisitInlineFragment(InlineFragmentNode node, IGraphQLNode? context)
         {
-            IGraphQLNode? newContext = context;
+            if (context == null)
+                throw new EntityGraphQLCompilerException("context should not be null visiting inline fragment");
 
-            if (node.TypeCondition is not null)
+            if (node.TypeCondition is not null && context is not null)
             {
                 var type = schemaProvider.GetSchemaType(node.TypeCondition.Name.Value, requestContext);
                 if (type != null)
-                {
-                    //animals = animals.Select(a => a is Dog ? new { a.name, a.hasBone } :  new { a.name }
-
+                {                    
                     var fragParameter = Expression.Parameter(type.TypeDotnet, $"frag_{type.Name}");
-                    newContext = new GraphQLListSelectionField((GraphQLListSelectionField)context!, fragParameter);
+                    var newContext = new GraphQLListSelectionField((GraphQLListSelectionField)context!, fragParameter);
+                    base.VisitInlineFragment(node, newContext);
+
+                    //copy the fragment fields over to the select context and cast the type so we can access the property
+                    foreach (var queryField in newContext.QueryFields)
+                    {
+                        var resolveExpression = Expression.Condition(
+                              test: Expression.TypeIs(context.NextFieldContext, type.TypeDotnet),
+                              ifTrue: Expression.Property(Expression.Convert(context.NextFieldContext, type.TypeDotnet), queryField.Name),
+                              ifFalse: Expression.Default(queryField.NextFieldContext?.Type)
+                        );
+
+                        var fieldResult = new GraphQLScalarField(schemaProvider, queryField.Field, queryField.Name, resolveExpression!, queryField.NextFieldContext as ParameterExpression ?? context.RootParameter, context, queryField.Arguments as Dictionary<string, object>);                        
+                        context.AddField(fieldResult);
+                    }
+                }
+                else
+                {
+                    base.VisitInlineFragment(node, context);
                 }
             }
-
-            base.VisitInlineFragment(node, newContext);
-        }        
+        }
 
         protected override void VisitFragmentSpread(FragmentSpreadNode node, IGraphQLNode? context)
         {

diff --git a/src/EntityGraphQL/Compiler/GqlNodes/BaseGraphQLField.cs b/src/EntityGraphQL/Compiler/GqlNodes/BaseGraphQLField.cs
@@ -33,7 +33,7 @@ public abstract class BaseGraphQLField : IGraphQLNode
         public string Name { get; }
         public IField? Field { get; }
         public List<BaseGraphQLField> QueryFields { get; } = new();
-        public Expression? NextFieldContext { get; set; }
+        public Expression? NextFieldContext { get; }
         public IGraphQLNode? ParentNode { get; }
         public ParameterExpression? RootParameter { get; set; }
         /// <summary>

diff --git a/src/EntityGraphQL/Compiler/GqlNodes/ExecutableGraphQLStatement.cs b/src/EntityGraphQL/Compiler/GqlNodes/ExecutableGraphQLStatement.cs
@@ -18,7 +18,7 @@ namespace EntityGraphQL.Compiler
     /// </summary>
     public abstract class ExecutableGraphQLStatement : IGraphQLNode
     {
-        public Expression? NextFieldContext { get; set; }
+        public Expression? NextFieldContext { get; }
         public IGraphQLNode? ParentNode { get; }
         public ParameterExpression? RootParameter { get; }
         /// <summary>

diff --git a/src/EntityGraphQL/Compiler/GqlNodes/GraphQLDocument.cs b/src/EntityGraphQL/Compiler/GqlNodes/GraphQLDocument.cs
@@ -26,7 +26,7 @@ namespace EntityGraphQL.Compiler
     /// </summary>
     public class GraphQLDocument : IGraphQLNode
     {
-        public Expression? NextFieldContext { get; set; }
+        public Expression? NextFieldContext { get; }
         public IGraphQLNode? ParentNode { get; }
         public ParameterExpression? RootParameter { get; }
         public List<BaseGraphQLField> QueryFields { get; } = new List<BaseGraphQLField>();

diff --git a/src/EntityGraphQL/Compiler/GqlNodes/GraphQLFragmentStatement.cs b/src/EntityGraphQL/Compiler/GqlNodes/GraphQLFragmentStatement.cs
@@ -6,7 +6,7 @@ namespace EntityGraphQL.Compiler
 {
     public class GraphQLFragmentStatement : IGraphQLNode
     {
-        public Expression? NextFieldContext { get; set; }
+        public Expression? NextFieldContext { get; }
         public IGraphQLNode? ParentNode { get;  }
         public ParameterExpression? RootParameter { get; }
 

diff --git a/src/EntityGraphQL/Compiler/GqlNodes/IGraphQLNode.cs b/src/EntityGraphQL/Compiler/GqlNodes/IGraphQLNode.cs
@@ -7,7 +7,7 @@ namespace EntityGraphQL.Compiler
     public interface IGraphQLNode
     {
         string Name { get; }
-        Expression? NextFieldContext { get; set; }
+        Expression? NextFieldContext { get; }
         IGraphQLNode? ParentNode { get; }
         ParameterExpression? RootParameter { get; }
 

diff --git a/src/tests/EntityGraphQL.Tests/QueryTests/QueryTests.cs b/src/tests/EntityGraphQL.Tests/QueryTests/QueryTests.cs
@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using EntityGraphQL.Tests.ApiVersion1;
 using Microsoft.CSharp.RuntimeBinder;
+using Microsoft.EntityFrameworkCore;
 
 namespace EntityGraphQL.Tests
 {
@@ -356,7 +357,6 @@ public void TestInheritance()
         name
     }
 }");
-
             var context = new TestAbstractDataContext();
             context.Animals.Add(new Dog() { Name = "steve", HasBone = true });
             context.Animals.Add(new Cat() { Name = "george", Lives = 9 });
@@ -398,13 +398,14 @@ ...on Dog {
             // we only have the fields requested
             Assert.Equal(2, animals.Count);
 
-
             Assert.Equal("Dog", animals[0].__typename);
             Assert.Equal("steve", animals[0].name);
             Assert.True(animals[0].hasBone);
             Assert.Equal("Cat", animals[1].__typename);
             Assert.Equal("george", animals[1].name);
             Assert.Equal(9, animals[1].lives);
         }
+
+
     }
 }
diff --git a/src/tests/EntityGraphQL.Tests/TestAbstractDataContext.cs b/src/tests/EntityGraphQL.Tests/TestAbstractDataContext.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System;
+using Microsoft.EntityFrameworkCore;
 
 namespace EntityGraphQL.Tests
 {