--- a/spec/util_error_spec.lua	Fri Sep 25 16:39:22 2020 +0100
+++ b/spec/util_error_spec.lua	Sat Sep 26 17:16:34 2020 +0200
@@ -66,5 +66,13 @@
 		end);
 	end);
 
+	describe("extra", function ()
+		it("keeps some extra fields", function ()
+			local err = errors.new({condition="gone",text="Sorry mate, it's all gone",extra={uri="file:///dev/null"}});
+			assert.is_table(err.extra);
+			assert.equal("file:///dev/null", err.extra.uri);
+		end);
+	end)
+
 end);
 

--- a/util/error.lua	Fri Sep 25 16:39:22 2020 +0100
+++ b/util/error.lua	Sat Sep 26 17:16:34 2020 +0200
@@ -43,6 +43,7 @@
 				type = e.type;
 				condition = e.condition;
 				text = e.text;
+				extra = e.extra;
 			};
 		else
 			template = {};
@@ -61,6 +62,7 @@
 		condition = template.condition or "undefined-condition";
 		text = template.text;
 		code = template.code;
+		extra = template.extra;
 
 		context = context;
 		source = source;