Fail if multiple kubeconfig files are set.

The environment variable 'KUBECONFIG' supports declaring multiple kubeconfig files but not the flag '--kubeconfig'.
Marking the plugin validation as failure due to the above limitation since plugins rely on falg '--kubeconfig' over 'KUBECONFIG'

cmd/commands.go

@@ -65,7 +65,7 @@ func getRunCommand() *cobra.Command {
 
 			if !drifts.SkipValidation {
 				if !drifts.ValidatePrerequisite() {
-					return &errors.PreValidationError{Message: "validation failed, please install prerequisites to identify drifts"}
+					return &errors.PreValidationError{Message: "validation failed, please address the prerequisite errors to identify drifts"}
 				}
 			}
 
@@ -102,7 +102,7 @@ Do note that this is expensive operation since multiple kubectl command would be
 
 			if !drifts.SkipValidation {
 				if !drifts.ValidatePrerequisite() {
-					return &errors.PreValidationError{Message: "validation failed, please install prerequisites to identify drifts"}
+					return &errors.PreValidationError{Message: "validation failed, please address the prerequisite errors to identify drifts"}
 				}
 			}
 

pkg/from_release.go

@@ -7,6 +7,7 @@ import (
 	"helm.sh/helm/v3/pkg/action"
 	"helm.sh/helm/v3/pkg/cli"
 	"helm.sh/helm/v3/pkg/release"
+
 	// Import to initialize client auth plugins.
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
 )
@@ -24,9 +25,8 @@ func (drift *Drift) getChartFromRelease() ([]byte, error) {
 		settings.KubeContext = kubeContext
 	}
 
-	kubeConfig := drift.kubeConfig //nolint:ifshort
-	if len(kubeConfig) != 0 {
-		settings.KubeConfig = kubeConfig
+	if len(drift.kubeConfig) != 0 {
+		settings.KubeConfig = drift.kubeConfig
 	}
 
 	if err := actionConfig.Init(settings.RESTClientGetter(), settings.Namespace(), os.Getenv("HELM_DRIVER"), log.Printf); err != nil {

pkg/validation.go

@@ -2,12 +2,28 @@ package pkg
 
 import (
 	"errors"
+	"fmt"
 	"os/exec"
+	"strings"
+)
+
+const (
+	docLink = "https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/" +
+		"#append-home-kube-config-to-your-kubeconfig-environment-variable"
 )
 
 func (drift *Drift) ValidatePrerequisite() bool {
 	success := true
 
+	if len(strings.Split(drift.kubeConfig, ":")) > 1 {
+		drift.log.Info("since drift uses kubectl underneath with arg '--kubeconfig' " +
+			"drift cannot run with multiple kubeconfig files set under environment var 'KUBECONFIG', " +
+			"like mentioned in below document")
+		fmt.Printf("%s\n", docLink)
+
+		success = false
+	}
+
 	if goPath := exec.Command("kubectl"); goPath.Err != nil {
 		if !errors.Is(goPath.Err, exec.ErrDot) {
 			drift.log.Infof("%v", goPath.Err.Error())