What version of protobuf and what language are you using?
Version: master, Go

What did you do?

With the parseNumber function:

func main() {
	n, ok := parseNumber([]byte("1234,anything can come after the comma"))
	if ok {
		panic(fmt.Sprintf("should not be ok, %d", n))
	}
}

panics with should not be ok, 4, indicating that it parsed "1234,anything can come after the comma" into the integer 1234, even though this should really throw an error.

What did you expect to see?

ok == false

What did you see instead?

ok == true

Anything else we should know about your project / environment?
No