Support interface unexported methods

codegen/interface_build.go

@@ -78,7 +78,7 @@ func (cfg *Config) isValueReceiver(intf *NamedType, implementor *NamedType, prog
 	for i := 0; i < interfaceType.NumMethods(); i++ {
 		intfMethod := interfaceType.Method(i)
 
-		implMethod := findMethod(implementorType, intfMethod.Name())
+		implMethod := findMethod(implementorType, intfMethod.Name(), false)
 		if implMethod == nil {
 			fmt.Fprintf(os.Stderr, "missing method %s on %s\n", intfMethod.Name(), implementor.GoType)
 			return false

codegen/util.go

@@ -73,10 +73,14 @@ func findGoInterface(prog *loader.Program, pkgName string, typeName string) (*ty
 	return underlying, nil
 }
 
-func findMethod(typ *types.Named, name string) *types.Func {
+func findExportedMethod(typ *types.Named, name string) *types.Func {
+	return findMethod(typ, name, true)
+}
+
+func findMethod(typ *types.Named, name string, onlyExported bool) *types.Func {
 	for i := 0; i < typ.NumMethods(); i++ {
 		method := typ.Method(i)
-		if !method.Exported() {
+		if !method.Exported() && onlyExported {
 			continue
 		}
 
@@ -93,7 +97,7 @@ func findMethod(typ *types.Named, name string) *types.Func {
 			}
 
 			if named, ok := field.Type().(*types.Named); ok {
-				if f := findMethod(named, name); f != nil {
+				if f := findExportedMethod(named, name); f != nil {
 					return f
 				}
 			}
@@ -144,7 +148,7 @@ func bindObject(t types.Type, object *Object, imports *Imports) error {
 
 	for i := range object.Fields {
 		field := &object.Fields[i]
-		if method := findMethod(namedType, field.GQLName); method != nil {
+		if method := findExportedMethod(namedType, field.GQLName); method != nil {
 			sig := method.Type().(*types.Signature)
 			field.GoMethodName = "obj." + method.Name()
 			field.Type.Modifiers = modifiersFromGoType(sig.Results().At(0).Type())

example/iface/.gqlgen.yml

@@ -0,0 +1,12 @@
+schema: schema.graphql
+exec:
+  filename: generated.go
+model:
+  filename: models_gen.go
+models:
+  Bar:
+    model: github.com/vektah/gqlgen/example/iface/models.Bar
+  Entity:
+    model: github.com/vektah/gqlgen/example/iface/models.Entity
+  Foo:
+    model: github.com/vektah/gqlgen/example/iface/models.Foo