TestChannelSpec/InMemoryChannel-messaging.knative.dev/v1beta1 flake, when trying to update subscribers.

[vaikas]

Describe the bug
In:
https://prow.knative.dev/view/gcs/knative-prow/logs/ci-knative-eventing-continuous/1299178242036469761

The test failed with:

=== FAIL: test/conformance TestChannelSpec/InMemoryChannel-messaging.knative.dev/v1beta1 (3.57s)
    test_runner.go:148: namespace is : "test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd"
    channel_spec_test_helper.go:56: Running channel spec conformance test with channel {InMemoryChannel messaging.knative.dev/v1beta1}
    channel_spec_test_helper.go:134: Creating channel {Kind:InMemoryChannel APIVersion:messaging.knative.dev/v1beta1}-channel-tmp-5bp48
    creation.go:77: Creating channel &TypeMeta{Kind:InMemoryChannel,APIVersion:messaging.knative.dev/v1beta1,}-channel-tmp-5bp48
    channel_spec_test_helper.go:65: Creating channel {Kind:InMemoryChannel APIVersion:messaging.knative.dev/v1beta1}-channel-spec-subscribers-vf7v7
    creation.go:77: Creating channel &TypeMeta{Kind:InMemoryChannel,APIVersion:messaging.knative.dev/v1beta1,}-channel-spec-subscribers-vf7v7
    channel_spec_test_helper.go:126: Error updating {InMemoryChannel messaging.knative.dev/v1beta1} with subscribers in spec: conversion webhook for messaging.knative.dev/v1, Kind=InMemoryChannel failed: Post https://eventing-webhook.knative-eventing-jon9h3t4lv.svc:443/resource-conversion?timeout=30s: EOF
    test_runner.go:193: EVENT: {{ } {test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd.162f53d578e1dd04  test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd /api/v1/namespaces/test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd/events/test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd.162f53d578e1dd04 b9620ca3-13d8-431e-9ef0-deb7681c0227 1071 0 2020-08-28 04:22:49 +0000 UTC <nil> <nil> map[] map[] [] []  []} {Namespace test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd test-channel-spec-in-memory-channel-messaging-knative-dev-fwdmd 9ddb1199-0cc1-45d1-a535-628f5df23e96 v1 7834 } BrokerCreated Default eventing.knative.dev Broker created. {namespace-controller } 2020-08-28 04:22:49 +0000 UTC 2020-08-28 04:22:49 +0000 UTC 1 Normal 0001-01-01 00:00:00 +0000 UTC nil  nil  }

We should probably wrap this with the retry helper:
https://github.com/knative/eventing/blob/master/test/conformance/helpers/channel_spec_test_helper.go#L122

Expected behavior
A clear and concise description of what you expected to happen.

To Reproduce
Steps to reproduce the behavior.

Knative release version

Additional context
Add any other context about the problem here such as proposed priority

[aliok]

The entire test is within a retry loop, but it doesn't completely solve the problem I think: https://github.com/knative/eventing/blob/master/test/conformance/helpers/channel_spec_test_helper.go#L58

I want to add something in that line you pointed at, but not sure what :) ? retryConflict may not work there.

[pierDipi]

We need to use the following method:

eventing/test/lib/creation.go

Line 66 in 0f8e0c8

func (c *Client) RetryWebhookErrors(updater func(int) error) error {

[aliok]

hmm, got it, let me give it a try

[aliok]

Trial here: #3971

[aliok]

/assign