Return an error on unrecognized arguments when running default commands in Prysm (#9129)

* Return an error on unrecognized arguments when running default commands in Prysm

* fix cases for subcommands

* Deepsource suggestion

cmd/beacon-chain/main.go

@@ -177,7 +177,10 @@ func main() {
 			runtimeDebug.SetGCPercent(ctx.Int(flags.SetGCPercent.Name))
 		}
 		runtime.GOMAXPROCS(runtime.NumCPU())
-		return debug.Setup(ctx)
+		if err := debug.Setup(ctx); err != nil {
+			return err
+		}
+		return cmd.ValidateNoArgs(ctx)
 	}
 
 	defer func() {

cmd/client-stats/main.go

@@ -84,7 +84,7 @@ func main() {
 				log.WithError(err).Error("Failed to configuring logging to disk.")
 			}
 		}
-		return nil
+		return cmd.ValidateNoArgs(ctx)
 	}
 
 	defer func() {

cmd/slasher/main.go

@@ -132,7 +132,10 @@ func main() {
 		}
 
 		runtime.GOMAXPROCS(runtime.NumCPU())
-		return debug.Setup(ctx)
+		if err := debug.Setup(ctx); err != nil {
+			return err
+		}
+		return cmd.ValidateNoArgs(ctx)
 	}
 
 	app.After = func(ctx *cli.Context) error {

cmd/validator/main.go

@@ -168,7 +168,10 @@ func main() {
 		}
 
 		runtime.GOMAXPROCS(runtime.NumCPU())
-		return debug.Setup(ctx)
+		if err := debug.Setup(ctx); err != nil {
+			return err
+		}
+		return cmd.ValidateNoArgs(ctx)
 	}
 
 	app.After = func(ctx *cli.Context) error {

shared/cmd/flags.go

@@ -2,6 +2,9 @@
 package cmd
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/altsrc"
@@ -250,3 +253,17 @@ func LoadFlagsFromConfig(cliCtx *cli.Context, flags []cli.Flag) error {
 	}
 	return nil
 }
+
+// ValidateNoArgs insures that the application is not run with erroneous arguments or flags.
+// This function should be used in the app.Before, whenever the application supports a default command.
+func ValidateNoArgs(ctx *cli.Context) error {
+	for _, a := range ctx.Args().Slice() {
+		if strings.HasPrefix(a, "-") {
+			continue
+		}
+		if c := ctx.App.Command(a); c == nil {
+			return fmt.Errorf("unrecognized argument: %s", a)
+		}
+	}
+	return nil
+}

shared/cmd/flags_test.go

@@ -40,3 +40,35 @@ func TestLoadFlagsFromConfig(t *testing.T) {
 	require.NoError(t, command.Run(context))
 	require.NoError(t, os.Remove("flags_test.yaml"))
 }
+
+func TestValidateNoArgs(t *testing.T) {
+	app := &cli.App{
+		Before: ValidateNoArgs,
+		Action: func(c *cli.Context) error {
+			return nil
+		},
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name: "foo",
+			},
+		},
+		Commands: []*cli.Command{
+			{
+				Name: "bar",
+			},
+		},
+	}
+
+	// It should not work with a bogus argument
+	err := app.Run([]string{"command", "foo"})
+	require.ErrorContains(t, "unrecognized argument: foo", err)
+	// It should work with registered flags
+	err = app.Run([]string{"command", "--foo=bar"})
+	require.NoError(t, err)
+	// It should work with subcommands.
+	err = app.Run([]string{"command", "bar"})
+	require.NoError(t, err)
+	// It should fail on unregistered flag (default logic in urfave/cli).
+	err = app.Run([]string{"command", "bar", "--baz"})
+	require.ErrorContains(t, "flag provided but not defined", err)
+}