dnsx/plus: use errored transports iff post-filter count is low

Author: ignoramous

intra/dnsx/plus.go

@@ -168,12 +168,12 @@ func (t *plus) ordered() ([]Transport, error) {
 	ord = append(ord, recov...)
 
 	ord = core.CopyUniq(ord)
-	if len(ord) < plusMaxTries {
-		ord = core.CopyUniq(ord, errored)
-	}
 
 	prev := ord
 	strat := settings.PlusStrat.Load()
+
+	refiltered := false
+refilter:
 	switch strat {
 	case settings.PlusFilterSafest:
 		ord = core.FilterLeft(ord, IsEncrypted)
@@ -185,6 +185,12 @@ func (t *plus) ordered() ([]Transport, error) {
 		// nothing to do
 	}
 
+	if !refiltered && len(ord) < plusMaxTries {
+		ord = core.CopyUniq(ord, errored)
+		refiltered = true
+		goto refilter
+	}
+
 	if len(ord) <= 0 {
 		log.W("plus: strat %d: zero transports avail [exp: %d]: sys? %s / pref: %s / errored: %v / ended: %v",
 			strat, expected, idstr(sys), infcsv(preferred...), infcsv(errored...), infcsv(ended...))