openapi3: empty scopes are valid (#754)

Author: nodar963

openapi3/security_scheme.go

@@ -363,8 +363,8 @@ func (flow *OAuthFlow) Validate(ctx context.Context, opts ...ValidationOption) e
 		}
 	}
 
-	if v := flow.Scopes; len(v) == 0 {
-		return errors.New("field 'scopes' is empty or missing")
+	if flow.Scopes == nil {
+		return errors.New("field 'scopes' is missing")
 	}
 
 	return validateExtensions(ctx, flow.Extensions)

openapi3/security_scheme_test.go

@@ -197,7 +197,7 @@ var securitySchemeExamples = []securitySchemeExample{
     }
   }
 }`),
-		valid: false,
+		valid: true,
 	},
 
 	{