net: don't forget about ongoing DNS lookup if context canceled
Only forget about it if the context timed out, as the comment says.
Fixes #20703.
Change-Id: Ie6234f1a32f85e6bfd052dc24a33aa63b8883c37
Reviewed-on: https://go-review.googlesource.com/45999
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/net/lookup.go b/src/net/lookup.go
index abc56de..4490784 100644
--- a/src/net/lookup.go
+++ b/src/net/lookup.go
@@ -185,12 +185,15 @@
select {
case <-ctx.Done():
- // The DNS lookup timed out for some reason. Force
+ // If the DNS lookup timed out for some reason, force
// future requests to start the DNS lookup again
// rather than waiting for the current lookup to
// complete. See issue 8602.
- err := mapErr(ctx.Err())
- lookupGroup.Forget(host)
+ ctxErr := ctx.Err()
+ if ctxErr == context.DeadlineExceeded {
+ lookupGroup.Forget(host)
+ }
+ err := mapErr(ctxErr)
if trace != nil && trace.DNSDone != nil {
trace.DNSDone(nil, false, err)
}
