Fix: deepObject return without assign on !required

Author: voro015

bindparam.go

@@ -469,7 +469,7 @@ func BindQueryParameter(style string, explode bool, required bool, paramName str
 		if !explode {
 			return errors.New("deepObjects must be exploded")
 		}
-		return UnmarshalDeepObject(dest, paramName, queryParams)
+		return unmarshalDeepObject(dest, paramName, queryParams, required)
 	case "spaceDelimited", "pipeDelimited":
 		return fmt.Errorf("query arguments of style '%s' aren't yet supported", style)
 	default:

bindparam_test.go

@@ -322,6 +322,10 @@ func TestBindQueryParameter(t *testing.T) {
 		err := BindQueryParameter("deepObject", true, false, paramName, queryParams, &actual)
 		assert.NoError(t, err)
 		assert.Equal(t, expectedDeepObject, actual)
+
+		// If we require values, we require errors when they're not present.
+		err = BindQueryParameter("deepObject", true, true, "notfound", queryParams, &actual)
+		assert.Error(t, err)
 	})
 
 	t.Run("form", func(t *testing.T) {

deepobject.go

@@ -124,6 +124,10 @@ func makeFieldOrValue(paths [][]string, values []string) fieldOrValue {
 }
 
 func UnmarshalDeepObject(dst interface{}, paramName string, params url.Values) error {
+	return unmarshalDeepObject(dst, paramName, params, false)
+}
+
+func unmarshalDeepObject(dst interface{}, paramName string, params url.Values, required bool) error {
 	// Params are all the query args, so we need those that look like
 	// "paramName["...
 	var fieldNames []string
@@ -141,6 +145,14 @@ func UnmarshalDeepObject(dst interface{}, paramName string, params url.Values) e
 		}
 	}
 
+	if len(fieldNames) == 0 {
+		if required {
+			return fmt.Errorf("query parameter '%s' is required", paramName)
+		} else {
+			return nil
+		}
+	}
+
 	// Now, for each field, reconstruct its subscript path and value
 	paths := make([][]string, len(fieldNames))
 	for i, path := range fieldNames {