Merge pull request #13 from dgraph-io/jatin/Fix-stringPanic

fix(GraphQL): fix validation when we give non-string value in variable and expected type is string.

Author: JatinDev543

validator/vars.go

@@ -145,6 +145,7 @@ func (v *varValidator) validateVarType(typ *ast.Type, val reflect.Value) (reflec
 		return val, nil
 	case ast.Scalar:
 		kind := val.Type().Kind()
+		namedType := val.Type().Name()
 		switch typ.NamedType {
 		case "Int", "Int64":
 			if kind == reflect.String || kind == reflect.Int || kind == reflect.Int32 || kind == reflect.Int64 {
@@ -176,7 +177,7 @@ func (v *varValidator) validateVarType(typ *ast.Type, val reflect.Value) (reflec
 				return val, nil
 			}
 		case "String":
-			if kind == reflect.String {
+			if namedType == "string" {
 				return val, nil
 			}
 

validator/walk.go

@@ -59,7 +59,7 @@ type Walker struct {
 	Observers                *Events
 	Schema                   *ast.Schema
 	Document                 *ast.QueryDocument
-	Variables                map[string]interface{}
+	Variables                map[string]interface{} // These variables are not coerced
 	validatedFragmentSpreads map[string]bool
 	CurrentOperation         *ast.OperationDefinition
 }