Merge pull request #53483 from apelisse/openapi-columns

Automatic merge from submit-queue (batch tested with PRs 50457, 55558, 53483, 55731, 52842). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Show openapi custom columns in `kubectl get`

Change the name of the flag to something slightly more user-friendly,
while making it default true. The flag is kept so that someone can
revert it temporarly if things go wrong.

**What this PR does / why we need it**: OpenAPI can specify for some columns to be used in `kubectl get`. That's very useful for non-core/hard-coded type in order to print more valuable data in get.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

Closes kubernetes/kubectl#143

**Release note**:
```release-note
`kubectl get` will now use OpenAPI schema extensions by default to select columns for custom types.
```

pkg/kubectl/cmd/util/openapi/testing/openapi.go

@@ -121,3 +121,20 @@ func (f *FakeResources) LookupResource(gvk schema.GroupVersionKind) proto.Schema
 	}
 	return resources.LookupResource(gvk)
 }
+
+// EmptyResources implement a Resources that just doesn't have any resources.
+type EmptyResources struct{}
+
+var _ openapi.Resources = EmptyResources{}
+
+// LookupResource will always return nil. It doesn't have any resources.
+func (f EmptyResources) LookupResource(gvk schema.GroupVersionKind) proto.Schema {
+	return nil
+}
+
+// CreateOpenAPISchemaFunc returns a function useful for the TestFactory.
+func CreateOpenAPISchemaFunc(path string) func() (openapi.Resources, error) {
+	return func() (openapi.Resources, error) {
+		return NewFakeResources(path), nil
+	}
+}