net: TestLookupDotsWithRemoteSource is flaky

[katiehockman]

#!watchflakes
post <- pkg == "net" && test == "TestLookupDotsWithRemoteSource" && (`DNS server failure`||`no such host`||`server misbehaving`||`timeout period expired`)

We are getting flaky test failures in net. This has been somewhat rare in the past few months, but it has failed the last 5 builds, so probably worth looking into now.

--- FAIL: TestLookupDotsWithRemoteSource (15.57s)
    lookup_test.go:694: LookupSRV(xmpp-server, tcp, google.com): lookup _xmpp-server._tcp.google.com on 8.8.8.8:53: read udp 10.50.0.170:50511->8.8.8.8:53: i/o timeout (mode=go)
FAIL
FAIL	net	30.123s

Looks very related to #16865 closed 2 years ago.

[katiehockman]

/cc @mikioh @brad-burch @ianlancetaylor

[ianlancetaylor]

2018-06-13T18:06:14-537fb06/darwin-amd64-10_10
2018-06-13T18:06:14-537fb06/darwin-amd64-10_11
2018-06-26T16:40:09-8997ec1/darwin-amd64-10_10
2018-06-26T16:40:09-8997ec1/darwin-amd64-10_11
2018-06-26T16:40:09-8997ec1/darwin-amd64-race
2018-07-03T16:14:43-2ee6bfb/darwin-amd64-10_10
2018-07-03T16:14:43-2ee6bfb/darwin-amd64-10_12
2018-07-03T16:27:51-aad71d3/darwin-amd64-10_12
2018-07-03T17:37:40-5d4f047/darwin-386-10_11
2018-07-03T17:37:40-5d4f047/darwin-amd64-10_10
2018-07-03T17:37:40-5d4f047/darwin-amd64-10_11
2018-07-09T22:19:21-94076fe/darwin-amd64-10_10
2018-07-11T01:08:56-5e70b13/darwin-amd64-race
2018-07-27T16:29:52-b39fb9e/darwin-amd64-10_10
2018-08-17T15:34:50-876c6d1/darwin-386-10_11
2018-08-17T15:34:50-876c6d1/darwin-amd64-10_10
2018-08-17T15:34:50-876c6d1/darwin-amd64-10_11
2018-08-21T04:39:22-80fe2e6/darwin-amd64-race
2018-08-21T04:50:21-2a5df06/darwin-386-10_11
2018-08-21T04:55:04-187a41d/darwin-amd64-10_10
2018-08-21T04:55:04-187a41d/darwin-amd64-10_11
2018-08-21T14:08:12-e8daca4/darwin-amd64-10_10
2018-08-22T22:11:24-ccb70bd/darwin-386-10_11
2018-08-24T23:02:01-aacc891/darwin-amd64-10_10
2018-08-24T23:02:31-523dc5a/darwin-amd64-10_10
2018-08-30T19:36:15-a2a8396/darwin-amd64-10_10
2018-08-30T19:36:15-a2a8396/darwin-amd64-race
2018-10-03T15:01:47-c96e3bc/darwin-amd64-10_10
2018-10-03T19:52:49-cbafcc5/darwin-amd64-10_10
2018-10-03T19:54:16-9a8372f/darwin-amd64-10_10
2018-10-03T19:54:29-c91ce3c/darwin-386-10_11
2018-10-03T19:54:29-c91ce3c/darwin-amd64-10_10
2018-10-03T19:54:29-c91ce3c/darwin-amd64-race
2018-10-03T20:13:35-112f28d/darwin-amd64-10_10

[ianlancetaylor]

Any chance there was a recent change to whether the builders set GO_BUILDER_FLAKY_NET in the environment? Because the test does not fail in that way if that environment variable is set.

[mikioh]

Once http://golang.org/cl/102875 lands, I will smash the use of external DNS speakers such as rsc.io or some public full resolver then flaky tests disappear. For now, I have no spare time to debug the circumstances running the tests, also not sure there's a way to sneak in the (protected) circumstances.

[andybons]

@mikioh should we just disable this test until 1.13?

[mikioh]

Yes, please. Will try to allocate my spare time for Go 1.13 devel cycle.

[gopherbot]

Change https://golang.org/cl/151799 mentions this issue: net: skip flaky TestLookupDotsWithRemoteSource for now