reset to nil, replace tab wtih space (#6352)

modules/openapi-generator/src/main/resources/go-experimental/model_oneof.mustache

@@ -40,6 +40,11 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
 
 	{{/oneOf}}
 	if match > 1 { // more than 1 match
+		// reset to nil
+		{{#oneOf}}
+		dst.{{{.}}} = nil
+		{{/oneOf}}
+
 		return fmt.Errorf("Data matches more than one schema in oneOf({{classname}})")
 	} else if match == 1 {
 		return nil // exactly one match

samples/openapi3/client/petstore/go-experimental/go-petstore/model_fruit.go

@@ -62,6 +62,10 @@ func (dst *Fruit) UnmarshalJSON(data []byte) error {
 	}
 
 	if match > 1 { // more than 1 match
+		// reset to nil
+		dst.Apple = nil
+		dst.Banana = nil
+
 		return fmt.Errorf("Data matches more than one schema in oneOf(Fruit)")
 	} else if match == 1 {
 		return nil // exactly one match

samples/openapi3/client/petstore/go-experimental/go-petstore/model_fruit_req.go

@@ -62,6 +62,10 @@ func (dst *FruitReq) UnmarshalJSON(data []byte) error {
 	}
 
 	if match > 1 { // more than 1 match
+		// reset to nil
+		dst.AppleReq = nil
+		dst.BananaReq = nil
+
 		return fmt.Errorf("Data matches more than one schema in oneOf(FruitReq)")
 	} else if match == 1 {
 		return nil // exactly one match

samples/openapi3/client/petstore/go-experimental/go-petstore/model_mammal.go

@@ -62,6 +62,10 @@ func (dst *Mammal) UnmarshalJSON(data []byte) error {
 	}
 
 	if match > 1 { // more than 1 match
+		// reset to nil
+		dst.Whale = nil
+		dst.Zebra = nil
+
 		return fmt.Errorf("Data matches more than one schema in oneOf(Mammal)")
 	} else if match == 1 {
 		return nil // exactly one match