From 8bc49c945c1b393bcfb4d8df545c93593c9bd7c4 Mon Sep 17 00:00:00 2001
From: thinkofher <mail@bdudek.xyz>
Date: Sun, 18 Sep 2022 21:20:05 +0200
Subject: [PATCH] mime/multipart: use %w when wrapping error in NextPart

Use "%w" instead of "%v" as format verb for error value in the NextPart
method. This way it will be possible to use common go error utilities
from std library when parsing from custom io.Readers.

This issue was discovered during attempts to use
http.Request.ParseMultipartForm together with http.MaxBytesHandler.
---
 src/mime/multipart/multipart.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mime/multipart/multipart.go b/src/mime/multipart/multipart.go
index aa05ac8f9c..b3a904f0af 100644
--- a/src/mime/multipart/multipart.go
+++ b/src/mime/multipart/multipart.go
@@ -360,7 +360,7 @@ func (r *Reader) nextPart(rawPart bool) (*Part, error) {
 			return nil, io.EOF
 		}
 		if err != nil {
-			return nil, fmt.Errorf("multipart: NextPart: %v", err)
+			return nil, fmt.Errorf("multipart: NextPart: %w", err)
 		}
 
 		if r.isBoundaryDelimiterLine(line) {