Merge pull request #110436 from nicks/nicks/issue-1108

client-go: fix panic in ConfirmUsable validation

Kubernetes-commit: 349efaabf89cf894d3f7ef16f3936318ae96728e

go.mod

@@ -24,7 +24,7 @@ require (
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
 	golang.org/x/time v0.0.0-20220210224613-90d013bbcef8
 	google.golang.org/protobuf v1.27.1
-	k8s.io/api v0.0.0-20220614194928-60387f6ceb7c
+	k8s.io/api v0.0.0-20220614194929-edebc6706dde
 	k8s.io/apimachinery v0.0.0-20220614194717-c5be38573c73
 	k8s.io/klog/v2 v2.60.1
 	k8s.io/kube-openapi v0.0.0-20220603121420-31174f50af60
@@ -63,6 +63,6 @@ require (
 )
 
 replace (
-	k8s.io/api => k8s.io/api v0.0.0-20220614194928-60387f6ceb7c
+	k8s.io/api => k8s.io/api v0.0.0-20220614194929-edebc6706dde
 	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20220614194717-c5be38573c73
 )

go.sum

@@ -513,8 +513,8 @@ honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWh
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
 honnef.co/go/tools v0.0.1-2020.1.3/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
 honnef.co/go/tools v0.0.1-2020.1.4/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=
-k8s.io/api v0.0.0-20220614194928-60387f6ceb7c h1:DC+Zvr6/68fhuaIy5pTL0W4bAhbrnZi4jxozgPQ6vp0=
+k8s.io/api v0.0.0-20220614194929-edebc6706dde h1:uI3Bauw5zHxpzCFMum9XlALU5iK37yEiAZgKdVUQHGA=
-k8s.io/api v0.0.0-20220614194928-60387f6ceb7c/go.mod h1:GLhFhgtyTRwgH456jroUFHnl0QFlRJ7RFJ41U7TgOZc=
+k8s.io/api v0.0.0-20220614194929-edebc6706dde/go.mod h1:GLhFhgtyTRwgH456jroUFHnl0QFlRJ7RFJ41U7TgOZc=
 k8s.io/apimachinery v0.0.0-20220614194717-c5be38573c73 h1:EBei3PXKAoJZbqTqFYcQVh/wJcgXA/X1w7m8tBDyi3s=
 k8s.io/apimachinery v0.0.0-20220614194717-c5be38573c73/go.mod h1:iknpugsBdD8jeaGNZyi85Q334Mj3GFqi1SEHEEB/KQM=
 k8s.io/gengo v0.0.0-20210813121822-485abfe95c7c/go.mod h1:FiNAH4ZV3gBg2Kwh89tzAEV2be7d5xI0vBa/VySYy3E=

tools/clientcmd/validation.go

@@ -204,8 +204,19 @@ func ConfirmUsable(config clientcmdapi.Config, passedContextName string) error {
 
 	if exists {
 		validationErrors = append(validationErrors, validateContext(contextName, *context, config)...)
-		validationErrors = append(validationErrors, validateAuthInfo(context.AuthInfo, *config.AuthInfos[context.AuthInfo])...)
+
-		validationErrors = append(validationErrors, validateClusterInfo(context.Cluster, *config.Clusters[context.Cluster])...)
+		// Default to empty users and clusters and let the validation function report an error.
+		authInfo := config.AuthInfos[context.AuthInfo]
+		if authInfo == nil {
+			authInfo = &clientcmdapi.AuthInfo{}
+		}
+		validationErrors = append(validationErrors, validateAuthInfo(context.AuthInfo, *authInfo)...)
+
+		cluster := config.Clusters[context.Cluster]
+		if cluster == nil {
+			cluster = &clientcmdapi.Cluster{}
+		}
+		validationErrors = append(validationErrors, validateClusterInfo(context.Cluster, *cluster)...)
 	}
 
 	return newErrConfigurationInvalid(validationErrors)

tools/clientcmd/validation_test.go

@@ -65,6 +65,42 @@ func TestConfirmUsableBadInfoButOkConfig(t *testing.T) {
 	badValidation.testConfig(t)
 }
 
+func TestConfirmUsableMissingObjects(t *testing.T) {
+	config := clientcmdapi.NewConfig()
+	config.Clusters["kind-cluster"] = &clientcmdapi.Cluster{
+		Server: "anything",
+	}
+	config.AuthInfos["kind-user"] = &clientcmdapi.AuthInfo{
+		Token: "any-value",
+	}
+	config.Contexts["missing-user"] = &clientcmdapi.Context{
+		Cluster:  "kind-cluster",
+		AuthInfo: "garbage",
+	}
+	config.Contexts["missing-cluster"] = &clientcmdapi.Context{
+		Cluster:  "garbage",
+		AuthInfo: "kind-user",
+	}
+
+	missingUser := configValidationTest{
+		config: config,
+		expectedErrorSubstring: []string{
+			`user "garbage" was not found for context "missing-user"`,
+		},
+	}
+	missingUser.testConfirmUsable("missing-user", t)
+	missingUser.testConfig(t)
+
+	missingCluster := configValidationTest{
+		config: config,
+		expectedErrorSubstring: []string{
+			`cluster "garbage" was not found for context "missing-cluster"`,
+		},
+	}
+	missingCluster.testConfirmUsable("missing-cluster", t)
+	missingCluster.testConfig(t)
+}
+
 func TestConfirmUsableBadInfoConfig(t *testing.T) {
 	config := clientcmdapi.NewConfig()
 	config.Clusters["missing ca"] = &clientcmdapi.Cluster{