Closed
Description
What version of Go are you using (go version)?
$ go version go version go1.18.1 darwin/arm64
Does this issue reproduce with the latest release?
yes
What operating system and processor architecture are you using (go env)?
go env Output
$ go env GOARCH="arm64" GOHOSTARCH="arm64" GOHOSTOS="darwin"
What did you do?
// a function to read a line from STDIN and output the line to STDOUT
func LargeDataLine(r io.Reader, w io.Writer) {
s := ReadWithReadLine(r)
w.Write([]byte(s))
}
// Read with Readline function
func read(r *bufio.Reader) ([]byte, error) {
var (
isPrefix = true
err error
line, ln []byte
)
for isPrefix && err == nil {
line, isPrefix, err = r.ReadLine()
ln = append(ln, line...)
}
return ln, err
}
func ReadWithReadLine(r io.Reader) string {
reader := bufio.NewReader(r)
var line []byte
var err error
for {
line, err = read(reader)
if err != nil {
if err == io.EOF {
break
}
log.Fatalf("a real error happened here: %v\n", err)
}
// log.Println("readWithReadLine:")
// log.Println(string(line))
return string(line)
}
return ""
}
Testing:
Temporary redirecting Stdout
tempStdout := os.Stdout
r, w, _ := os.Pipe()
os.Stdout = w
dbfolder := "../test-data/"
testdataFile := fmt.Sprintf("%stestdata/testdata_%d.csv", dbfolder, i)
file, _ := os.Open(testdataFile)
defer file.Close()
r := bufio.NewReader(file)
s := ReadWithReadLine(r)
LargeDataLine(strings.NewReader(s), os.Stdout)
w.Close()
out, _ := ioutil.ReadAll(r)
os.Stdout = tempStdout
LargeDataLineStr := string(out)
What did you expect to see?
w.Write([]byte(s)) working with a line of hundreds of megabytes.
What did you see instead?
Waiting forever on the following: w.Write([]byte(s))