tink-cli: Ensure opt.RetrieveData is non-nil before invoking

Otherwise we get a nice panic.

Signed-off-by: Manuel Mendez <github@i.m.mmlb.dev>

cmd/tink-cli/cmd/get/get.go

@@ -67,6 +67,9 @@ func NewGetCommand(opt Options) *cobra.Command {
 			if len(args) != 0 {
 				data, err = retrieveMulti(cmd.Context(), opt, client, args)
 			} else {
+				if opt.RetrieveData == nil {
+					return errors.New("get-all-data is not implemented for this resource yet, please have a look at the issue in GitHub or open a new one")
+				}
 				data, err = opt.RetrieveData(cmd.Context(), client)
 			}
 			if err != nil {

cmd/tink-cli/cmd/get/get_test.go

@@ -214,6 +214,10 @@ func TestNewGetCommand(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name:        "no opts",
+			ExpectError: errors.New("get-all-data is not implemented for this resource yet, please have a look at the issue in GitHub or open a new one"),
+		},
 	}
 
 	for _, s := range tests {