Merge pull request #65377 from juanvallejo/jvallejo/restore-old-get-template-behavior

Automatic merge from submit-queue (batch tested with PRs 65377, 63837, 65370, 65294, 65376). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

restore pre-1.11 behavior of `kubectl get --template=...`

**Release note**:
```release-note
NONE
```

Restores old behavior to the `--template` flag in `get.go`.
In old releases, providing a `--template` flag value and no `--output` value implicitly assigned a default value ("go-template") to `--output`, printing using the provided template argument.

Example:

```bash
# this should print using GoTemplate printer, but currently does not
$ kubectl get pod foo --template="{{ .metadata.name }}"
```

cc @deads2k @soltysh

hack/make-rules/test-cmd-util.sh

@@ -1620,6 +1620,10 @@ run_kubectl_get_tests() {
   ## check --allow-missing-template-keys defaults to true for go templates
   kubectl get "${kube_flags[@]}" pod valid-pod -o go-template='{{.missing}}'
 
+  ## check --template flag causes go-template to be printed, even when no --output value is provided
+  output_message=$(kubectl get "${kube_flags[@]}" pod valid-pod --template="{{$id_field}}:")
+  kube::test::if_has_string "${output_message}" 'valid-pod:'
+
   ## check --allow-missing-template-keys=false results in an error for a missing key with jsonpath
   output_message=$(! kubectl get pod valid-pod --allow-missing-template-keys=false -o jsonpath='{.missing}' "${kube_flags[@]}")
   kube::test::if_has_string "${output_message}" 'missing is not found'

pkg/kubectl/cmd/get/get.go

@@ -212,8 +212,13 @@ func (o *GetOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []stri
 		o.ServerPrint = false
 	}
 
+	templateArg := ""
+	if o.PrintFlags.TemplateFlags != nil && o.PrintFlags.TemplateFlags.TemplateArgument != nil {
+		templateArg = *o.PrintFlags.TemplateFlags.TemplateArgument
+	}
+
 	// human readable printers have special conversion rules, so we determine if we're using one.
-	if len(*o.PrintFlags.OutputFormat) == 0 || *o.PrintFlags.OutputFormat == "wide" {
+	if (len(*o.PrintFlags.OutputFormat) == 0 && len(templateArg) == 0) || *o.PrintFlags.OutputFormat == "wide" {
 		o.IsHumanReadablePrinter = true
 	}
 

pkg/kubectl/cmd/get/get_flags.go

@@ -33,9 +33,9 @@ import (
 type PrintFlags struct {
 	JSONYamlPrintFlags *genericclioptions.JSONYamlPrintFlags
 	NamePrintFlags     *genericclioptions.NamePrintFlags
-	TemplateFlags      *printers.KubeTemplatePrintFlags
 	CustomColumnsFlags *printers.CustomColumnsPrintFlags
 	HumanReadableFlags *HumanPrintFlags
+	TemplateFlags      *printers.KubeTemplatePrintFlags
 
 	NoHeaders    *bool
 	OutputFormat *string
@@ -117,6 +117,15 @@ func (f *PrintFlags) ToPrinter() (printers.ResourcePrinter, error) {
 	f.HumanReadableFlags.NoHeaders = noHeaders
 	f.CustomColumnsFlags.NoHeaders = noHeaders
 
+	// for "get.go" we want to support a --template argument given, even when no --output format is provided
+	if f.TemplateFlags.TemplateArgument != nil && len(*f.TemplateFlags.TemplateArgument) > 0 && len(outputFormat) == 0 {
+		outputFormat = "go-template"
+	}
+
+	if p, err := f.TemplateFlags.ToPrinter(outputFormat); !genericclioptions.IsNoCompatiblePrinterError(err) {
+		return p, err
+	}
+
 	if f.TemplateFlags.TemplateArgument != nil {
 		f.CustomColumnsFlags.TemplateArgument = *f.TemplateFlags.TemplateArgument
 	}
@@ -129,10 +138,6 @@ func (f *PrintFlags) ToPrinter() (printers.ResourcePrinter, error) {
 		return p, err
 	}
 
-	if p, err := f.TemplateFlags.ToPrinter(outputFormat); !genericclioptions.IsNoCompatiblePrinterError(err) {
-		return p, err
-	}
-
 	if p, err := f.CustomColumnsFlags.ToPrinter(outputFormat); !genericclioptions.IsNoCompatiblePrinterError(err) {
 		return p, err
 	}