Revert "io: detect Writers that access io.Copy's buffer after returning"

This reverts CL 466865.

Reason for revert: Causing trybot flakiness due to net/http race,
roll back until net/http is fixed.

For #58168

Change-Id: I3129deb996abe6466eccf933fe93cbbaf72ae217
Reviewed-on: https://go-review.googlesource.com/c/go/+/467895
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Damien Neil <dneil@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Damien Neil <dneil@google.com>

diff --git a/src/io/io.go b/src/io/io.go
index 946ea5b01cac5ac52c81a01f0c85d72a1de51052..630ab73b56f4f18b091d9284b3b06377a3d36ecd 100644 (file)
--- a/src/io/io.go
+++ b/src/io/io.go
@@ -14,7 +14,6 @@ package io
 
 import (
        "errors"
-       "internal/race"
        "sync"
 )
 
@@ -428,14 +427,6 @@ func copyBuffer(dst Writer, src Reader, buf []byte) (written int64, err error) {
                nr, er := src.Read(buf)
                if nr > 0 {
                        nw, ew := dst.Write(buf[0:nr])
-                       if race.Enabled {
-                               // Write over the buffer to help the race detector
-                               // detect Write calls that access the buffer after returning.
-                               // Use something other than zeros to make errors more obvious.
-                               for i := range buf[:nr] {
-                                       buf[i] = 0xdd
-                               }
-                       }
                        if nw < 0 || nr < nw {
                                nw = 0
                                if ew == nil {