Revert "Kubelet flags take precedence over config from files/ConfigMaps"

This reverts commit cbebb61450.

cmd/kubelet/kubelet.go

@@ -53,7 +53,7 @@ func main() {
 	}
 	options.AddKubeletConfigFlags(pflag.CommandLine, defaultConfig)
 
-	// initialize pflag and parse the initial command line flags into the respective objects
+	// parse the command line flags into the respective objects
 	flag.InitFlags()
 
 	// initialize logging and defer flush
@@ -80,12 +80,6 @@ func main() {
 		die(err)
 	}
 
-	// re-parse the command-line flags on top of the returned configuration
-	// we layer flags over file-based and remote configuration to
-	// preserve backwards compatibility across binary upgrades
-	// see issue #56171 for more details
-	pflag.Parse()
-
 	// construct a KubeletServer from kubeletFlags and kubeletConfig
 	kubeletServer := &options.KubeletServer{
 		KubeletFlags:         *kubeletFlags,

hack/make-rules/test.sh

@@ -69,7 +69,6 @@ kube::test::find_dirs() {
         -o -path './vendor/k8s.io/client-go/*' \
         -o -path './vendor/k8s.io/apiserver/*' \
         -o -path './test/e2e_node/system/*' \
-        -o -path './test/e2e_node/services/*' \
       -name '*_test.go' -print0 | xargs -0n1 dirname | sed "s|^\./|${KUBE_GO_PACKAGE}/|" | LC_ALL=C sort -u
 
     # run tests for client-go

test/e2e_node/dynamic_kubelet_config_test.go

@@ -25,7 +25,6 @@ import (
 
 	apiv1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/pkg/kubelet/apis/kubeletconfig"
 	"k8s.io/kubernetes/pkg/kubelet/kubeletconfig/status"
 
@@ -47,8 +46,6 @@ var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:DynamicKube
 	f := framework.NewDefaultFramework("dynamic-kubelet-configuration-test")
 	var originalKC *kubeletconfig.KubeletConfiguration
 	var originalConfigMap *apiv1.ConfigMap
-	// local messages/reasons, depending on whether we expect the default or init config
-	var curLocalMessage, lkgLocalMessage, curLocalOKReason string
 
 	// Dummy context to prevent framework's AfterEach from cleaning up before this test's AfterEach can run
 	Context("", func() {
@@ -61,7 +58,6 @@ var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:DynamicKube
 				originalConfigMap, err = f.ClientSet.CoreV1().ConfigMaps("kube-system").Create(originalConfigMap)
 				framework.ExpectNoError(err)
 			}
-
 			// make sure Dynamic Kubelet Configuration feature is enabled on the Kubelet we are about to test
 			enabled, err := isKubeletConfigEnabled(f)
 			framework.ExpectNoError(err)
@@ -70,19 +66,6 @@ var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:DynamicKube
 					"Pass --feature-gates=DynamicKubeletConfig=true to the Kubelet to enable this feature.\n" +
 					"For `make test-e2e-node`, you can set `TEST_ARGS='--feature-gates=DynamicKubeletConfig=true'`."))
 			}
-
-			// expect different local messages/reasons depending on how Kuebelet is configured
-			if v, ok := originalKC.FeatureGates[string(features.KubeletConfigFile)]; !ok || !v {
-				// KubeletConfigFile key not found or set to false. It's still an alpha feature, so it is turned off by default.
-				curLocalMessage = status.CurDefaultMessage
-				lkgLocalMessage = status.LkgDefaultMessage
-				curLocalOKReason = status.CurDefaultOKReason
-			} else {
-				// KubeletConfigFile key was found and set to true.
-				curLocalMessage = status.CurInitMessage
-				lkgLocalMessage = status.LkgInitMessage
-				curLocalOKReason = status.CurInitOKReason
-			}
 		})
 
 		AfterEach(func() {
@@ -136,8 +119,8 @@ var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:DynamicKube
 					{desc: "Node.Spec.ConfigSource is nil",
 						configSource: nil,
 						expectConfigOK: &apiv1.NodeCondition{Type: apiv1.NodeConfigOK, Status: apiv1.ConditionTrue,
-							Message: curLocalMessage,
-							Reason:  curLocalOKReason},
+							Message: status.CurDefaultMessage,
+							Reason:  status.CurDefaultOKReason},
 						expectConfig: nil},
 
 					// Node.Spec.ConfigSource has all nil subfields
@@ -187,7 +170,7 @@ var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:DynamicKube
 							Namespace: failParseConfigMap.Namespace,
 							Name:      failParseConfigMap.Name}},
 						expectConfigOK: &apiv1.NodeCondition{Type: apiv1.NodeConfigOK, Status: apiv1.ConditionFalse,
-							Message: lkgLocalMessage,
+							Message: status.LkgDefaultMessage,
 							Reason:  fmt.Sprintf(status.CurFailParseReasonFmt, failParseConfigMap.UID)},
 						expectConfig: nil},
 
@@ -198,7 +181,7 @@ var _ = framework.KubeDescribe("DynamicKubeletConfiguration [Feature:DynamicKube
 							Namespace: failValidateConfigMap.Namespace,
 							Name:      failValidateConfigMap.Name}},
 						expectConfigOK: &apiv1.NodeCondition{Type: apiv1.NodeConfigOK, Status: apiv1.ConditionFalse,
-							Message: lkgLocalMessage,
+							Message: status.LkgDefaultMessage,
 							Reason:  fmt.Sprintf(status.CurFailValidateReasonFmt, failValidateConfigMap.UID)},
 						expectConfig: nil},
 				}

test/e2e_node/jenkins/jenkins-ci-ubuntu.properties

@@ -6,7 +6,6 @@ GCE_ZONE=us-central1-f
 GCE_PROJECT=k8s-jkns-ubuntu-node
 CLEANUP=true
 GINKGO_FLAGS='--skip="\[Flaky\]|\[Serial\]"'
-TEST_ARGS='--feature-gates=KubeletConfigFile=true'
 KUBELET_ARGS='--cgroups-per-qos=true --cgroup-root=/'
 TIMEOUT=1h
 # Use the system spec defined in test/e2e_node/system/specs/gke.yaml.

test/e2e_node/jenkins/jenkins-ci.properties

@@ -4,6 +4,5 @@ GCE_ZONE=us-central1-f
 GCE_PROJECT=k8s-jkns-ci-node-e2e
 CLEANUP=true
 GINKGO_FLAGS='--skip="\[Flaky\]|\[Serial\]"'
-TEST_ARGS='--feature-gates=KubeletConfigFile=true'
 KUBELET_ARGS='--cgroups-per-qos=true --cgroup-root=/'
 TIMEOUT=1h

test/e2e_node/jenkins/jenkins-flaky.properties

@@ -4,7 +4,7 @@ GCE_ZONE=us-central1-f
 GCE_PROJECT=k8s-jkns-ci-node-e2e
 CLEANUP=true
 GINKGO_FLAGS='--focus="\[Flaky\]"'
-TEST_ARGS='--feature-gates=KubeletConfigFile=true,DynamicKubeletConfig=true,LocalStorageCapacityIsolation=true,PodPriority=true'
+TEST_ARGS='--feature-gates=DynamicKubeletConfig=true,LocalStorageCapacityIsolation=true,PodPriority=true'
 KUBELET_ARGS='--cgroups-per-qos=true --cgroup-root=/'
 PARALLELISM=1
 TIMEOUT=3h

test/e2e_node/jenkins/jenkins-pull.properties

@@ -4,5 +4,5 @@ GCE_ZONE=us-central1-f
 GCE_PROJECT=k8s-jkns-pr-node-e2e
 CLEANUP=true
 GINKGO_FLAGS='--skip="\[Flaky\]|\[Slow\]|\[Serial\]" --flakeAttempts=2'
-TEST_ARGS='--feature-gates=KubeletConfigFile=true'
 KUBELET_ARGS='--cgroups-per-qos=true --cgroup-root=/'
+

test/e2e_node/jenkins/jenkins-serial-ubuntu.properties

@@ -6,7 +6,7 @@ GCE_ZONE=us-central1-f
 GCE_PROJECT=k8s-jkns-ubuntu-node-serial
 CLEANUP=true
 GINKGO_FLAGS='--focus="\[Serial\]" --skip="\[Flaky\]|\[Benchmark\]"'
-TEST_ARGS='--feature-gates=KubeletConfigFile=true,DynamicKubeletConfig=true'
+TEST_ARGS='--feature-gates=DynamicKubeletConfig=true'
 KUBELET_ARGS='--cgroups-per-qos=true --cgroup-root=/'
 PARALLELISM=1
 TIMEOUT=3h

test/e2e_node/jenkins/jenkins-serial.properties

@@ -4,7 +4,7 @@ GCE_ZONE=us-west1-b
 GCE_PROJECT=k8s-jkns-ci-node-e2e
 CLEANUP=true
 GINKGO_FLAGS='--focus="\[Serial\]" --skip="\[Flaky\]|\[Benchmark\]"'
-TEST_ARGS='--feature-gates=KubeletConfigFile=true,DynamicKubeletConfig=true'
+TEST_ARGS='--feature-gates=DynamicKubeletConfig=true'
 KUBELET_ARGS='--cgroups-per-qos=true --cgroup-root=/'
 PARALLELISM=1
 TIMEOUT=3h

test/e2e_node/services/BUILD

@@ -3,7 +3,6 @@ package(default_visibility = ["//visibility:public"])
 load(
     "@io_bazel_rules_go//go:def.bzl",
     "go_library",
-    "go_test",
 )
 
 go_library(
@@ -23,13 +22,9 @@ go_library(
     deps = [
         "//cmd/kube-apiserver/app:go_default_library",
         "//cmd/kube-apiserver/app/options:go_default_library",
-        "//cmd/kubelet/app/options:go_default_library",
         "//pkg/api/legacyscheme:go_default_library",
         "//pkg/controller/namespace:go_default_library",
         "//pkg/features:go_default_library",
-        "//pkg/kubelet/apis/kubeletconfig:go_default_library",
-        "//pkg/kubelet/apis/kubeletconfig/scheme:go_default_library",
-        "//pkg/kubelet/apis/kubeletconfig/v1alpha1:go_default_library",
         "//test/e2e/framework:go_default_library",
         "//test/e2e_node/builder:go_default_library",
         "//vendor/github.com/coreos/etcd/etcdserver:go_default_library",
@@ -38,9 +33,7 @@ go_library(
         "//vendor/github.com/coreos/etcd/pkg/types:go_default_library",
         "//vendor/github.com/golang/glog:go_default_library",
         "//vendor/github.com/kardianos/osext:go_default_library",
-        "//vendor/github.com/spf13/pflag:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
-        "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//vendor/k8s.io/apiserver/pkg/util/feature:go_default_library",
         "//vendor/k8s.io/client-go/dynamic:go_default_library",
         "//vendor/k8s.io/client-go/informers:go_default_library",
@@ -61,11 +54,3 @@ filegroup(
     srcs = [":package-srcs"],
     tags = ["automanaged"],
 )
-
-go_test(
-    name = "go_default_test",
-    srcs = ["kubelet_test.go"],
-    importpath = "k8s.io/kubernetes/test/e2e_node/services",
-    library = ":go_default_library",
-    deps = ["//vendor/github.com/spf13/pflag:go_default_library"],
-)

test/e2e_node/services/kubelet.go

@@ -27,15 +27,9 @@ import (
 	"strings"
 
 	"github.com/golang/glog"
-	"github.com/spf13/pflag"
 
-	"k8s.io/apimachinery/pkg/runtime"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
-	"k8s.io/kubernetes/cmd/kubelet/app/options"
 	"k8s.io/kubernetes/pkg/features"
-	"k8s.io/kubernetes/pkg/kubelet/apis/kubeletconfig"
-	"k8s.io/kubernetes/pkg/kubelet/apis/kubeletconfig/scheme"
-	"k8s.io/kubernetes/pkg/kubelet/apis/kubeletconfig/v1alpha1"
 	"k8s.io/kubernetes/test/e2e/framework"
 	"k8s.io/kubernetes/test/e2e_node/builder"
 )
@@ -124,7 +118,6 @@ func (e *E2EServices) startKubelet() (*server, error) {
 	var isSystemd bool
 	// Apply default kubelet flags.
 	cmdArgs := []string{}
-	kubeArgs := []string{}
 	if systemdRun, err := exec.LookPath("systemd-run"); err == nil {
 		// On systemd services, detection of a service / unit works reliably while
 		// detection of a process started from an ssh session does not work.
@@ -139,13 +132,13 @@ func (e *E2EServices) startKubelet() (*server, error) {
 			Name:              "kubelet.log",
 			JournalctlCommand: []string{"-u", unitName},
 		}
-		kubeArgs = append(kubeArgs,
+		cmdArgs = append(cmdArgs,
 			"--kubelet-cgroups=/kubelet.slice",
 			"--cgroup-root=/",
 		)
 	} else {
 		cmdArgs = append(cmdArgs, builder.GetKubeletServerBin())
-		kubeArgs = append(kubeArgs,
+		cmdArgs = append(cmdArgs,
 			// TODO(random-liu): Get rid of this docker specific thing.
 			"--runtime-cgroups=/docker-daemon",
 			"--kubelet-cgroups=/kubelet",
@@ -153,7 +146,7 @@ func (e *E2EServices) startKubelet() (*server, error) {
 			"--system-cgroups=/system",
 		)
 	}
-	kubeArgs = append(kubeArgs,
+	cmdArgs = append(cmdArgs,
 		"--kubeconfig", kubeconfigPath,
 		"--address", "0.0.0.0",
 		"--port", kubeletPort,
@@ -182,11 +175,11 @@ func (e *E2EServices) startKubelet() (*server, error) {
 
 	if utilfeature.DefaultFeatureGate.Enabled(features.DynamicKubeletConfig) {
 		// Enable dynamic config if the feature gate is enabled
-		dir, err := getDynamicConfigDirectory()
+		dynamicConfigDir, err := getDynamicConfigDir()
 		if err != nil {
 			return nil, err
 		}
-		kubeArgs = append(kubeArgs, "--dynamic-config-dir", dir)
+		cmdArgs = append(cmdArgs, "--dynamic-config-dir", dynamicConfigDir)
 	}
 
 	// Enable kubenet by default.
@@ -200,40 +193,18 @@ func (e *E2EServices) startKubelet() (*server, error) {
 		return nil, err
 	}
 
-	kubeArgs = append(kubeArgs,
+	cmdArgs = append(cmdArgs,
 		"--network-plugin=kubenet",
 		"--cni-bin-dir", cniBinDir,
 		"--cni-conf-dir", cniConfDir)
 
 	// Keep hostname override for convenience.
 	if framework.TestContext.NodeName != "" { // If node name is specified, set hostname override.
-		kubeArgs = append(kubeArgs, "--hostname-override", framework.TestContext.NodeName)
+		cmdArgs = append(cmdArgs, "--hostname-override", framework.TestContext.NodeName)
 	}
 
 	// Override the default kubelet flags.
-	kubeArgs = append(kubeArgs, kubeletArgs...)
-
-	// If the config file feature gate is enabled, generate the file and remove the flags it applies to
-	if utilfeature.DefaultFeatureGate.Enabled(features.KubeletConfigFile) {
-		kc, other, err := splitKubeletConfigArgs(kubeArgs)
-		if err != nil {
-			return nil, err
-		}
-		// replace kubeArgs with the new command line, which has had the KubeletConfiguration flags removed
-		kubeArgs = other
-		path, err := writeKubeletConfigFile(kc)
-		if err != nil {
-			return nil, err
-		}
-		// ensure the test context feature gates (typically DynamicKubeletConfig and KubeletConfigFile)
-		// are set on the command line
-		kubeArgs = append(kubeArgs, "--feature-gates", framework.TestContext.FeatureGates)
-		// add the flag to load config from a file
-		kubeArgs = append(kubeArgs, "--init-config-dir", filepath.Dir(path))
-	}
-
-	// combine the kubelet parameters with the command
-	cmdArgs = append(cmdArgs, kubeArgs...)
+	cmdArgs = append(cmdArgs, kubeletArgs...)
 
 	// Adjust the args if we are running kubelet with systemd.
 	if isSystemd {
@@ -253,94 +224,6 @@ func (e *E2EServices) startKubelet() (*server, error) {
 	return server, server.start()
 }
 
-// splitKubeletConfigArgs parses args onto a KubeletConfiguration object and also returns the unknown args
-func splitKubeletConfigArgs(args []string) (*kubeletconfig.KubeletConfiguration, []string, error) {
-	kc, err := options.NewKubeletConfiguration()
-	if err != nil {
-		return nil, nil, err
-	}
-	fs := pflag.NewFlagSet("kubeletconfig", pflag.ContinueOnError)
-	options.AddKubeletConfigFlags(fs, kc)
-	known, other := splitKnownArgs(fs, args)
-	if err := fs.Parse(known); err != nil {
-		return nil, nil, err
-	}
-	return kc, other, nil
-}
-
-// splitKnownArgs splits argument list into those known by the flagset, and those not known
-// only tests for longhand args, e.g. prefixed with `--`
-// TODO(mtaufen): I don't think the kubelet has any shorthand args, but if it does we will need to modify this.
-func splitKnownArgs(fs *pflag.FlagSet, args []string) ([]string, []string) {
-	known := []string{}
-	other := []string{}
-	lastFlag := len(args)
-	for i := len(args) - 1; i >= 0; i-- {
-		if strings.HasPrefix(args[i], "--") {
-			if fs.Lookup(strings.TrimPrefix(args[i], "--")) == nil {
-				// flag is unknown, add flag and params to other
-				// prepend to maintain order
-				other = append(append([]string(nil), args[i:lastFlag]...), other...)
-				// cut from known
-			} else {
-				// flag is known, add flag and params to known
-				// prepend to maintain order
-				known = append(append([]string(nil), args[i:lastFlag]...), known...)
-			}
-			// mark the last location where we saw a flag
-			lastFlag = i
-		}
-	}
-	return known, other
-}
-
-// writeKubeletConfigFile writes the kubelet config file based on the args and returns the filename
-func writeKubeletConfigFile(internal *kubeletconfig.KubeletConfiguration) (string, error) {
-	// extract the KubeletConfiguration and convert to versioned
-	versioned := &v1alpha1.KubeletConfiguration{}
-	scheme, _, err := scheme.NewSchemeAndCodecs()
-	if err != nil {
-		return "", err
-	}
-	if err := scheme.Convert(internal, versioned, nil); err != nil {
-		return "", err
-	}
-	// encode
-	encoder, err := newKubeletConfigJSONEncoder()
-	if err != nil {
-		return "", err
-	}
-	data, err := runtime.Encode(encoder, versioned)
-	if err != nil {
-		return "", err
-	}
-	// create the init conifg directory
-	dir, err := createKubeletInitConfigDirectory()
-	if err != nil {
-		return "", err
-	}
-	// write init config file
-	path := filepath.Join(dir, "kubelet")
-	if err := ioutil.WriteFile(path, data, 0755); err != nil {
-		return "", err
-	}
-	return path, nil
-}
-
-func newKubeletConfigJSONEncoder() (runtime.Encoder, error) {
-	_, kubeletCodecs, err := scheme.NewSchemeAndCodecs()
-	if err != nil {
-		return nil, err
-	}
-
-	mediaType := "application/json"
-	info, ok := runtime.SerializerInfoForMediaType(kubeletCodecs.SupportedMediaTypes(), mediaType)
-	if !ok {
-		return nil, fmt.Errorf("unsupported media type %q", mediaType)
-	}
-	return kubeletCodecs.EncoderForVersion(info.Serializer, v1alpha1.SchemeGroupVersion), nil
-}
-
 // createPodManifestDirectory creates pod manifest directory.
 func createPodManifestDirectory() (string, error) {
 	cwd, err := os.Getwd()
@@ -430,7 +313,7 @@ func getCNIConfDirectory() (string, error) {
 }
 
 // getDynamicConfigDir returns the directory for dynamic Kubelet configuration
-func getDynamicConfigDirectory() (string, error) {
+func getDynamicConfigDir() (string, error) {
 	cwd, err := os.Getwd()
 	if err != nil {
 		return "", err
@@ -438,19 +321,6 @@ func getDynamicConfigDirectory() (string, error) {
 	return filepath.Join(cwd, "dynamic-kubelet-config"), nil
 }
 
-// createKubeletInitConfigDirectory creates and returns the name of the directory for dynamic Kubelet configuration
-func createKubeletInitConfigDirectory() (string, error) {
-	cwd, err := os.Getwd()
-	if err != nil {
-		return "", err
-	}
-	path := filepath.Join(cwd, "init-kubelet-config")
-	if err := os.MkdirAll(path, 0755); err != nil {
-		return "", err
-	}
-	return path, nil
-}
-
 // adjustArgsForSystemd escape special characters in kubelet arguments for systemd. Systemd
 // may try to do auto expansion without escaping.
 func adjustArgsForSystemd(args []string) {

test/e2e_node/services/kubelet_test.go

@@ -1,146 +0,0 @@
-/*
-Copyright 2017 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package services
-
-import (
-	"reflect"
-	"testing"
-
-	"github.com/spf13/pflag"
-)
-
-func TestSplitKnownArgs(t *testing.T) {
-	cases := []struct {
-		desc        string
-		args        []string
-		fs          *pflag.FlagSet
-		expectKnown []string
-		expectOther []string
-	}{
-		{
-			"splits three args:a",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "a", a, "")
-				return fs
-			}(),
-			[]string{"--a", "a"},
-			[]string{"--b", "b", "--c", "c"},
-		},
-		{
-			"splits three args:b",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "b", a, "")
-				return fs
-			}(),
-			[]string{"--b", "b"},
-			[]string{"--a", "a", "--c", "c"},
-		},
-		{
-			"splits three args:c",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "c", a, "")
-				return fs
-			}(),
-			[]string{"--c", "c"},
-			[]string{"--a", "a", "--b", "b"},
-		},
-		{
-			"splits three args:ab",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "a", a, "")
-				fs.StringVar(&a, "b", a, "")
-				return fs
-			}(),
-			[]string{"--a", "a", "--b", "b"},
-			[]string{"--c", "c"},
-		},
-		{
-			"splits three args:bc",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "b", a, "")
-				fs.StringVar(&a, "c", a, "")
-				return fs
-			}(),
-			[]string{"--b", "b", "--c", "c"},
-			[]string{"--a", "a"},
-		},
-		{
-			"splits three args:ac",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "a", a, "")
-				fs.StringVar(&a, "c", a, "")
-				return fs
-			}(),
-			[]string{"--a", "a", "--c", "c"},
-			[]string{"--b", "b"},
-		},
-		{
-			"splits three args:abc",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			func() *pflag.FlagSet {
-				fs := pflag.NewFlagSet("", pflag.ContinueOnError)
-				var a string
-				fs.StringVar(&a, "a", a, "")
-				fs.StringVar(&a, "b", a, "")
-				fs.StringVar(&a, "c", a, "")
-				return fs
-			}(),
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			[]string{},
-		},
-		{
-			"splits three args:none",
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-			pflag.NewFlagSet("", pflag.ContinueOnError),
-			[]string{},
-			[]string{"--a", "a", "--b", "b", "--c", "c"},
-		},
-	}
-	for _, c := range cases {
-		t.Run(c.desc, func(t *testing.T) {
-			origArgs := append([]string(nil), c.args...)
-			known, other := splitKnownArgs(c.fs, c.args)
-			if !reflect.DeepEqual(c.expectKnown, known) {
-				t.Errorf("expect known args to be %v, got %v", c.expectKnown, known)
-			}
-			if !reflect.DeepEqual(c.expectOther, other) {
-				t.Errorf("expect other args to be %v, got %v", c.expectOther, other)
-			}
-			if !reflect.DeepEqual(origArgs, c.args) {
-				t.Errorf("args was mutated")
-			}
-		})
-	}
-}