Skip publishing OpenAPI for nonstructural schemas

[liggitt]

What type of PR is this?
/kind bug

What this PR does / why we need it:

• Restores compatibility with 1.15 CRDs by not publishing openapi non-structural schemas
• Restores compatibility with 1.14 CRDs by not publishing openapi for structural schemas whose CRDs set spec.preserveUnknownFields=true

Which issue(s) this PR fixes:
Fixes #82651

Does this PR introduce a user-facing change?:

Restores compatibility with <=1.15.x custom resources by not publishing OpenAPI for non-structural custom resource definitions

/assign @roycaihw @sttts
/cc @aanm
/sig api-machinery

[liggitt]

/milestone v1.16
/priority critical-urgent

[liggitt]

/retest

[liggitt]

verified only {"type":"object"} definition is now published for:

• non-structural schemas
• structural schemas in CRDs with spec.preserveUnknownFields=true

[aanm]

I've test it out kube-apiserver rc.1 with this patch and it works again. Thanks @liggitt ! 🚤

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liggitt

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• staging/src/k8s.io/apiextensions-apiserver/OWNERS [liggitt]
• test/OWNERS [liggitt]

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[liggitt]

/retest

[sttts]

/lgtm

[liggitt]

grrr

diff -Naupr -x _output /home/prow/go/src/k8s.io/kubernetes/test/integration/master/BUILD /tmp/verify-bazel.PIXBfZ/go/src/k8s.io/kubernetes/test/integration/master/BUILD
--- /home/prow/go/src/k8s.io/kubernetes/test/integration/master/BUILD	2019-09-12 18:29:28.613188619 +0000
+++ /tmp/verify-bazel.PIXBfZ/go/src/k8s.io/kubernetes/test/integration/master/BUILD	2019-09-12 18:29:54.776436873 +0000
@@ -70,6 +70,7 @@ go_test(
         "//vendor/github.com/evanphx/json-patch:go_default_library",
         "//vendor/github.com/go-openapi/spec:go_default_library",
         "//vendor/github.com/stretchr/testify/require:go_default_library",
+        "//vendor/k8s.io/utils/pointer:go_default_library",
         "//vendor/sigs.k8s.io/yaml:go_default_library",
     ] + select({
         "@io_bazel_rules_go//go/platform:android": [

Run ./hack/update-bazel.sh

[k8s-ci-robot]

New changes are detected. LGTM label has been removed.

[liggitt]

bazel regenerated, retagged

[roycaihw]

LGTM

[roycaihw]

/area custom-resources

[alexellis]

@liggitt not sure if you mind the question here vs. another forum. Could this patch be related to a recent regression in the OpenFaaS CRD when taking K8s 1.17.5 and 1.18? openfaas/faas-netes#630 (comment)

[liggitt]

no, this is not related. what you are seeing might be related to #85127 (comment)