internal: transport nil should happen before backoff (#2392)

jeanbza · web-flow · commit e120c3f9007f · 2018-10-22T13:57:57.000-07:00
Seems to fix https://travis-ci.org/grpc/grpc-go/jobs/443409852, but regardless it's a more correct place for it to happen.
diff --git a/clientconn.go b/clientconn.go
@@ -965,6 +965,7 @@ func (ac *addrConn) resetTransport(resolveNow bool) {
 			ac.updateConnectivityState(connectivity.TransientFailure)
 			ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
 		}
+		ac.transport = nil
 		ac.mu.Unlock()
 
 		if err := ac.nextAddr(); err != nil {
@@ -976,7 +977,6 @@ func (ac *addrConn) resetTransport(resolveNow bool) {
 			ac.mu.Unlock()
 			return
 		}
-		ac.transport = nil
 
 		backoffIdx := ac.backoffIdx
 		backoffFor := ac.dopts.bs.Backoff(backoffIdx)

Original file line number	Diff line number	Diff line change
`@@ -965,6 +965,7 @@ func (ac *addrConn) resetTransport(resolveNow bool) {`
`965`	`965`	`ac.updateConnectivityState(connectivity.TransientFailure)`
`966`	`966`	`ac.cc.handleSubConnStateChange(ac.acbw, ac.state)`
`967`	`967`	`}`
	`968`	`+ ac.transport = nil`
`968`	`969`	`ac.mu.Unlock()`
`969`	`970`
`970`	`971`	`if err := ac.nextAddr(); err != nil {`
`@@ -976,7 +977,6 @@ func (ac *addrConn) resetTransport(resolveNow bool) {`
`976`	`977`	`ac.mu.Unlock()`
`977`	`978`	`return`
`978`	`979`	`}`
`979`		`- ac.transport = nil`
`980`	`980`
`981`	`981`	`backoffIdx := ac.backoffIdx`
`982`	`982`	`backoffFor := ac.dopts.bs.Backoff(backoffIdx)`