handle case where interface is type-asserted to same interface

Author: sqs

graphql_test.go

@@ -1726,6 +1726,31 @@ func TestInlineFragments(t *testing.T) {
 			`,
 		},
 
+		{
+			Schema: starwarsSchema,
+			Query: `
+				query CharacterSearch {
+					hero {
+						... on Character {
+							... on Human {
+								name
+							}
+							... on Droid {
+								name
+							}
+						}
+					}
+				}
+			`,
+			ExpectedResult: `
+				{
+					"hero": {
+						"name": "R2-D2"
+					}
+				}
+			`,
+		},
+
 		{
 			Schema: socialSchema,
 			Query: `
@@ -2992,27 +3017,27 @@ type helloInputMismatch struct {
 	World string
 }
 
-func (r *inputArgumentsHello) Hello(args struct { Input *helloInput }) string {
+func (r *inputArgumentsHello) Hello(args struct{ Input *helloInput }) string {
 	return "Hello " + args.Input.Name + "!"
 }
 
 func (r *inputArgumentsScalarMismatch1) Hello(name string) string {
 	return "Hello " + name + "!"
 }
 
-func (r *inputArgumentsScalarMismatch2) Hello(args struct { World string }) string {
+func (r *inputArgumentsScalarMismatch2) Hello(args struct{ World string }) string {
 	return "Hello " + args.World + "!"
 }
 
 func (r *inputArgumentsObjectMismatch1) Hello(in helloInput) string {
 	return "Hello " + in.Name + "!"
 }
 
-func (r *inputArgumentsObjectMismatch2) Hello(args struct { Input *helloInputMismatch }) string {
+func (r *inputArgumentsObjectMismatch2) Hello(args struct{ Input *helloInputMismatch }) string {
 	return "Hello " + args.Input.World + "!"
 }
 
-func (r *inputArgumentsObjectMismatch3) Hello(args struct { Input *struct { Thing string } }) string {
+func (r *inputArgumentsObjectMismatch3) Hello(args struct{ Input *struct{ Thing string } }) string {
 	return "Hello " + args.Input.Thing + "!"
 }
 

internal/exec/selected/selected.go

@@ -173,37 +173,39 @@ func applySelectionSet(r *Request, s *resolvable.Schema, e *resolvable.Object, s
 }
 
 func applyFragment(r *Request, s *resolvable.Schema, e *resolvable.Object, frag *query.Fragment) []Selection {
-	t := r.Schema.Resolve(frag.On.Name)
-	face, ok := t.(*schema.Interface)
-	if !ok && frag.On.Name != "" && frag.On.Name != e.Name {
-		a, ok := e.TypeAssertions[frag.On.Name]
-		if !ok {
-			panic(fmt.Errorf("%q does not implement %q", frag.On, e.Name)) // TODO proper error handling
+	if frag.On.Name != e.Name {
+		t := r.Schema.Resolve(frag.On.Name)
+		face, ok := t.(*schema.Interface)
+		if !ok && frag.On.Name != "" {
+			a, ok := e.TypeAssertions[frag.On.Name]
+			if !ok {
+				panic(fmt.Errorf("%q does not implement %q", frag.On, e.Name)) // TODO proper error handling
+			}
+
+			return []Selection{&TypeAssertion{
+				TypeAssertion: *a,
+				Sels:          applySelectionSet(r, s, a.TypeExec.(*resolvable.Object), frag.Selections),
+			}}
 		}
+		if ok && len(face.PossibleTypes) > 0 {
+			sels := []Selection{}
+			for _, t := range face.PossibleTypes {
+				if t.Name == e.Name {
+					return applySelectionSet(r, s, e, frag.Selections)
+				}
 
-		return []Selection{&TypeAssertion{
-			TypeAssertion: *a,
-			Sels:          applySelectionSet(r, s, a.TypeExec.(*resolvable.Object), frag.Selections),
-		}}
-	}
-	if ok && len(face.PossibleTypes) > 0 {
-		sels := []Selection{}
-		for _, t := range face.PossibleTypes {
-			if t.Name == e.Name {
-				return applySelectionSet(r, s, e, frag.Selections)
+				if a, ok := e.TypeAssertions[t.Name]; ok {
+					sels = append(sels, &TypeAssertion{
+						TypeAssertion: *a,
+						Sels:          applySelectionSet(r, s, a.TypeExec.(*resolvable.Object), frag.Selections),
+					})
+				}
 			}
-
-			if a, ok := e.TypeAssertions[t.Name]; ok {
-				sels = append(sels, &TypeAssertion{
-					TypeAssertion: *a,
-					Sels:          applySelectionSet(r, s, a.TypeExec.(*resolvable.Object), frag.Selections),
-				})
+			if len(sels) == 0 {
+				panic(fmt.Errorf("%q does not implement %q", e.Name, frag.On)) // TODO proper error handling
 			}
+			return sels
 		}
-		if len(sels) == 0 {
-			panic(fmt.Errorf("%q does not implement %q", e.Name, frag.On)) // TODO proper error handling
-		}
-		return sels
 	}
 	return applySelectionSet(r, s, e, frag.Selections)
 }