fix: stop discovery errors from halting chart rendering.

This blocks a particular error (caused by upstream discovery client),
printing a warning instead of failing. It's not a great solution, but is
a stop-gap until Client-Go gets fixed.

Closes helm#6361

Signed-off-by: Matt Butcher <matt.butcher@microsoft.com>

pkg/action/action.go

@@ -19,6 +19,7 @@ package action
 import (
 	"path"
 	"regexp"
+	"strings"
 
 	"github.com/pkg/errors"
 	"k8s.io/apimachinery/pkg/api/meta"
@@ -109,9 +110,19 @@ func (c *Configuration) getCapabilities() (*chartutil.Capabilities, error) {
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get server version from Kubernetes")
 	}
+	// There is a bug in upstream that causes this to fail when there are orphaned API services.
+	// To stop #6361 from killing charts, we will for now do some error scanning and print
+	// a warning when the above is the cause.
+	// See https://github.com/kubernetes/kubernetes/issues/72051#issuecomment-521157642
 	apiVersions, err := GetVersionSet(dc)
 	if err != nil {
-		return nil, errors.Wrap(err, "could not get apiVersions from Kubernetes")
+		if strings.Contains(err.Error(), "unable to retrieve the complete list") {
+			c.Log("WARNING: The Kubernetes server has an orphaned API server. Server reports: %s", err)
+			c.Log("WARNING: To fix this, kubectl delete apiservice <service-name>")
+			c.Log("WARNING: Until this is fixed, Helm will not be able to determine all of the types registered on this server.")
+		} else {
+			return nil, errors.Wrap(err, "could not get apiVersions from Kubernetes")
+		}
 	}
 
 	c.Capabilities = &chartutil.Capabilities{