It's a combination of : 1) A read and a write of a variable, happening without synchronization (see happens-before <https://golang.org/ref/mem#tmp_2>), is always a race, and always a bug, even when it "looks" innocuous. 2) When the receiver of a method is not a pointer, then this receiver is copied when the method is called. 3) (*RPC) compute() writes field result. 4) (RPC) version() copies the whole RPC value, which is a read to field result.
There is a data race on rpc.result On Sunday, April 2, 2017 at 11:57:59 PM UTC+2, st ov wrote: > > Could you explain how this is a race condition? > Running it in the playground appears to succeed, > https://play.golang.org/p/zs6T361fc6 > > > > > On Saturday, March 25, 2017 at 7:51:52 PM UTC-7, Dragos Harabor wrote: >> >> You may also run into subtle races when you mix pointer and value >> receivers, as seen here: >> https://dave.cheney.net/2015/11/18/wednesday-pop-quiz-spot-the-race >> >> >> On Friday, March 24, 2017 at 6:20:06 PM UTC-7, st ov wrote: >>> >>> Is it idiomatic to mix-&-match pointer and value method receivers for a >>> given type? >>> or in *general*, if a single method requires a pointer receiver than *all >>> methods* should take a pointer, regardless if a value receiver is >>> appropriate? >>> >>> For example, should Foo.SetVal also be a pointer receiver even though a >>> value receiver would be acceptable? >>> https://play.golang.org/p/rd_6BLol8O >>> >>> type Foo struct{ >>> ref []int >>> val int >>> } >>> >>> // would not set if method receiver is value receiver (foo Foo) >>> func (foo *Foo) SetRef(ref []int) { >>> foo.ref = ref >>> } >>> func (foo Foo) SetVal(val int) { >>> foo.val = val >>> } >>> >>> func main() { >>> foo := Foo{} >>> foo.SetRef([]int{1,2,3}) >>> foo.SetVal(1) >>> >>> fmt.Printf("%v",foo) // {[1 2 3] 0} >>> } >>> >>> >>> >>> -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
