From 52213cf67e156f00d3c1ca64fcf0a742f218ec45 Mon Sep 17 00:00:00 2001
From: Laurence Withers <l@lwithers.me.uk>
Date: Thu, 2 Apr 2020 12:25:23 +0100
Subject: [PATCH] cmd/htpacker: report filename on I/O error

---
 cmd/htpacker/yaml.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/htpacker/yaml.go b/cmd/htpacker/yaml.go
index eb8eaba..042932e 100644
--- a/cmd/htpacker/yaml.go
+++ b/cmd/htpacker/yaml.go
@@ -128,7 +128,7 @@ func filesFromListR(prefix, arg string, ftp packer.FilesToPack) error {
 		buf := make([]byte, 512)
 		n, err := f.Read(buf)
 		if err != nil {
-			return err
+			return fmt.Errorf("failed to read %s: %v", arg, err)
 		}
 		buf = buf[:n]
 		ctype := http.DetectContentType(buf)