From e3e1804ed2af1163335369300cfc562c35ffa4c9 Mon Sep 17 00:00:00 2001
From: Joel Sing <jsing@google.com>
Date: Wed, 25 Jan 2012 13:44:53 +1100
Subject: [PATCH] archive/tar: fix race in TestNonSeekable

Reimplement the test based on code from adg@golang.org.

The previous version has a race since the file is closed via defer
rather than in the go routine. This meant that the file could be
closed before the go routine has actually received io.EOF. It then
receives EBADF and continues to do zero-byte writes to the pipe.

This addresses an issue seen on FreeBSD and OpenBSD, where the test
passes but exits with a SIGPIPE, resulting in a failure.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/5554083
---
 src/pkg/archive/tar/reader_test.go | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/src/pkg/archive/tar/reader_test.go b/src/pkg/archive/tar/reader_test.go
index 0a6513d0ca..0a8646c393 100644
--- a/src/pkg/archive/tar/reader_test.go
+++ b/src/pkg/archive/tar/reader_test.go
@@ -240,31 +240,20 @@ func TestNonSeekable(t *testing.T) {
 	}
 	defer f.Close()
 
-	// pipe the data in
-	r, w, err := os.Pipe()
-	if err != nil {
-		t.Fatalf("Unexpected error %s", err)
+	type readerOnly struct {
+		io.Reader
 	}
-	go func() {
-		rdbuf := make([]uint8, 1<<16)
-		for {
-			nr, err := f.Read(rdbuf)
-			w.Write(rdbuf[0:nr])
-			if err == io.EOF {
-				break
-			}
-		}
-		w.Close()
-	}()
-
-	tr := NewReader(r)
+	tr := NewReader(readerOnly{f})
 	nread := 0
 
 	for ; ; nread++ {
-		hdr, err := tr.Next()
-		if hdr == nil || err == io.EOF {
+		_, err := tr.Next()
+		if err == io.EOF {
 			break
 		}
+		if err != nil {
+			t.Fatalf("Unexpected error: %v", err)
+		}
 	}
 
 	if nread != len(test.headers) {