feat(helm): add ability for --dry-run to do lookup functions

When a helm command is run with the --dry-run flag, it will try to connect to the cluster
to be able to render lookup functions.
Closes #8137

Signed-off-by: Tapas Kapadia <tapaskapadia10@gmail.com>

cmd/helm/install.go

@@ -142,7 +142,7 @@ func newInstallCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			}
 			client.SetRegistryClient(registryClient)
 
-			if client.DryRunOption == "unchanged" {
+			if client.DryRunOption == "" {
 				client.DryRunOption = "none"
 			}
 			rel, err := runInstall(args, client, valueOpts, out)
@@ -163,7 +163,7 @@ func newInstallCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 
 func addInstallFlags(cmd *cobra.Command, f *pflag.FlagSet, client *action.Install, valueOpts *values.Options) {
 	f.BoolVar(&client.CreateNamespace, "create-namespace", false, "create the release namespace if not present")
-	f.StringVar(&client.DryRunOption, "dry-run", "unchanged", "simulate an install. If --dry-run is set with no option being specified or as '--dry-run=client', it will not attempt cluster connections. Setting '--dry-run=server' allows attempting cluster connections.")
+	f.StringVar(&client.DryRunOption, "dry-run", "", "simulate an install. If --dry-run is set with no option being specified or as '--dry-run=client', it will not attempt cluster connections. Setting '--dry-run=server' allows attempting cluster connections.")
 	f.Lookup("dry-run").NoOptDefVal = "client"
 	f.BoolVar(&client.Force, "force", false, "force resource updates through a replacement strategy")
 	f.BoolVar(&client.DisableHooks, "no-hooks", false, "prevent hooks from running during install")

cmd/helm/template.go

@@ -79,7 +79,7 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			}
 			client.SetRegistryClient(registryClient)
 
-			if client.DryRunOption == "unchanged" {
+			if client.DryRunOption == "" {
 				client.DryRunOption = "true"
 			}
 			client.DryRun = true

cmd/helm/upgrade.go

@@ -96,7 +96,7 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 			}
 			client.SetRegistryClient(registryClient)
 
-			if client.DryRunOption == "unchanged" {
+			if client.DryRunOption == "" {
 				client.DryRunOption = "none"
 			}
 			// Fixes #7002 - Support reading values from STDIN for `upgrade` command
@@ -229,7 +229,7 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	f.BoolVar(&createNamespace, "create-namespace", false, "if --install is set, create the release namespace if not present")
 	f.BoolVarP(&client.Install, "install", "i", false, "if a release by this name doesn't already exist, run an install")
 	f.BoolVar(&client.Devel, "devel", false, "use development versions, too. Equivalent to version '>0.0.0-0'. If --version is set, this is ignored")
-	f.StringVar(&client.DryRunOption, "dry-run", "unchanged", "simulate an install. If --dry-run is set with no option being specified or as '--dry-run=client', it will not attempt cluster connections. Setting '--dry-run=server' allows attempting cluster connections.")
+	f.StringVar(&client.DryRunOption, "dry-run", "", "simulate an install. If --dry-run is set with no option being specified or as '--dry-run=client', it will not attempt cluster connections. Setting '--dry-run=server' allows attempting cluster connections.")
 	f.Lookup("dry-run").NoOptDefVal = "client"
 	f.BoolVar(&client.Recreate, "recreate-pods", false, "performs pods restart for the resource if applicable")
 	f.MarkDeprecated("recreate-pods", "functionality will no longer be updated. Consult the documentation for other methods to recreate pods")