bufio: Writer.ReadFrom ignores the stored error #35194
Description
If an error occurs writing to a Writer, no more data will be accepted and all subsequent writes, and Flush, will return the error.
type writer struct{}
func (w writer) Write(p []byte) (n int, err error) {
return 0, errors.New("bad move")
}
func main() {
var wr = bufio.NewWriter(writer{})
wr.WriteString("test1") // 5 <nil>
wr.Flush() // bad move
wr.ReadFrom(strings.NewReader("test2")) // 5 <nil>
wr.Buffered() // 10
}https://play.golang.org/p/--WBbDHbIS9
no more data will be accepted
Then I would expect ReadFrom to fail and the Buffered() count not to grow.
all subsequent writes [...] will return the error.
Isn't ReadFrom a write?
This seems unlikely to have bad consequences, but I don't think it's a valid reason for the documentation to be incorrect about corner cases.