Move `diff` command to root rather than alpha

New command is now `kubectl diff` rather than `kubectl alpha diff` since
it's moving out of alpha soon, and will be using dry-run apply to
produce the diff rather than the custom merge logic.

docs/.generated_docs

@@ -194,7 +194,6 @@ docs/man/man1/kubeadm-upgrade-plan.1
 docs/man/man1/kubeadm-upgrade.1
 docs/man/man1/kubeadm-version.1
 docs/man/man1/kubeadm.1
-docs/man/man1/kubectl-alpha-diff.1
 docs/man/man1/kubectl-alpha.1
 docs/man/man1/kubectl-annotate.1
 docs/man/man1/kubectl-api-resources.1
@@ -255,6 +254,7 @@ docs/man/man1/kubectl-create-serviceaccount.1
 docs/man/man1/kubectl-create.1
 docs/man/man1/kubectl-delete.1
 docs/man/man1/kubectl-describe.1
+docs/man/man1/kubectl-diff.1
 docs/man/man1/kubectl-drain.1
 docs/man/man1/kubectl-edit.1
 docs/man/man1/kubectl-exec.1
@@ -297,8 +297,6 @@ docs/man/man1/kubectl-wait.1
 docs/man/man1/kubectl.1
 docs/man/man1/kubelet.1
 docs/user-guide/kubectl/kubectl.md
-docs/user-guide/kubectl/kubectl_alpha.md
-docs/user-guide/kubectl/kubectl_alpha_diff.md
 docs/user-guide/kubectl/kubectl_annotate.md
 docs/user-guide/kubectl/kubectl_api-resources.md
 docs/user-guide/kubectl/kubectl_api-versions.md
@@ -358,6 +356,7 @@ docs/user-guide/kubectl/kubectl_create_service_nodeport.md
 docs/user-guide/kubectl/kubectl_create_serviceaccount.md
 docs/user-guide/kubectl/kubectl_delete.md
 docs/user-guide/kubectl/kubectl_describe.md
+docs/user-guide/kubectl/kubectl_diff.md
 docs/user-guide/kubectl/kubectl_drain.md
 docs/user-guide/kubectl/kubectl_edit.md
 docs/user-guide/kubectl/kubectl_exec.md
@@ -414,6 +413,7 @@ docs/yaml/kubectl/kubectl_cp.yaml
 docs/yaml/kubectl/kubectl_create.yaml
 docs/yaml/kubectl/kubectl_delete.yaml
 docs/yaml/kubectl/kubectl_describe.yaml
+docs/yaml/kubectl/kubectl_diff.yaml
 docs/yaml/kubectl/kubectl_drain.yaml
 docs/yaml/kubectl/kubectl_edit.yaml
 docs/yaml/kubectl/kubectl_exec.yaml

pkg/kubectl/cmd/alpha.go

@@ -36,7 +36,6 @@ func NewCmdAlpha(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.
 	// Alpha commands should be added here. As features graduate from alpha they should move
 	// from here to the CommandGroups defined by NewKubeletCommand() in cmd.go.
 	//cmd.AddCommand(NewCmdDebug(f, in, out, err))
-	cmd.AddCommand(NewCmdDiff(f, streams))
 
 	// NewKubeletCommand() will hide the alpha command if it has no subcommands. Overriding
 	// the help function ensures a reasonable message if someone types the hidden command anyway.

pkg/kubectl/cmd/cmd.go

@@ -468,6 +468,7 @@ func NewKubectlCommand(in io.Reader, out, err io.Writer) *cobra.Command {
 		{
 			Message: "Advanced Commands:",
 			Commands: []*cobra.Command{
+				NewCmdDiff(f, ioStreams),
 				NewCmdApply("kubectl", f, ioStreams),
 				NewCmdPatch(f, ioStreams),
 				NewCmdReplace(f, ioStreams),

pkg/kubectl/cmd/diff.go

@@ -54,10 +54,10 @@ var (
 		run with "-u" (unicode) and "-N" (treat new files as empty) options.`))
 	diffExample = templates.Examples(i18n.T(`
 		# Diff resources included in pod.json.
-		kubectl alpha diff -f pod.json
+		kubectl diff -f pod.json
 
 		# Diff file read from stdin
-		cat service.yaml | kubectl alpha diff -f -`))
+		cat service.yaml | kubectl diff -f -`))
 )
 
 type DiffOptions struct {

test/cmd/diff.sh

@@ -18,21 +18,21 @@ set -o errexit
 set -o nounset
 set -o pipefail
 
-# Runs tests for kubectl alpha diff
+# Runs tests for kubectl diff
 run_kubectl_diff_tests() {
     set -o nounset
     set -o errexit
 
     create_and_use_new_namespace
-    kube::log::status "Testing kubectl alpha diff"
+    kube::log::status "Testing kubectl diff"
 
     # Test that it works when the live object doesn't exist
-    output_message=$(kubectl alpha diff -f hack/testdata/pod.yaml)
+    output_message=$(kubectl diff -f hack/testdata/pod.yaml)
     kube::test::if_has_string "${output_message}" 'test-pod'
 
     kubectl apply -f hack/testdata/pod.yaml
 
-    output_message=$(kubectl alpha diff -f hack/testdata/pod-changed.yaml)
+    output_message=$(kubectl diff -f hack/testdata/pod-changed.yaml)
     kube::test::if_has_string "${output_message}" 'k8s.gcr.io/pause:3.0'
 
     kubectl delete -f  hack/testdata/pod.yaml