util.format: Escape invalid UTF-8 by passing trough serialization

Should prevent invalid UTF-8 from making it into the logs, which can
cause trouble with terminals or log viewers or other tools, such as when
grep determines that log files are binary.

1 files changed, 4 insertions, 0 deletions

diff --git a/spec/util_format_spec.lua b/spec/util_format_spec.lua
index d58c25aa..8d6ba8ad 100644
--- a/spec/util_format_spec.lua
+++ b/spec/util_format_spec.lua
@@ -20,5 +20,9 @@ describe("util.format", function()
 			assert.equal("␁", format("%s", "\1"));
 		end);
 
+		it("escapes invalid UTF-8", function ()
+			assert.equal("\"Hello w\\195rld\"", format("%s", "Hello w\195rld"));
+		end);
+
 	end);
 end);