chore(lib/cmd): improve invalid command errors (#2054)

Improve binary errors when subcommands are invalid or not specified,
reverting to default cobra behaviour.

issue: none

---------

Co-authored-by: Gregor G. <[email protected]>

e2e/app/rpc.go

@@ -66,8 +66,8 @@ func waitForHeight(ctx context.Context, testnet *e2e.Testnet, height int64) (*ty
 				}
 
 				result, err := currentBlock(ctx, client)
-				if errors.Is(err, context.DeadlineExceeded) {
-					return nil, nil, errors.Wrap(err, "timeout")
+				if ctx.Err() != nil {
+					return nil, nil, errors.Wrap(err, "parent context canceled")
 				} else if err != nil {
 					continue
 				}

halo/cmd/cmd_internal_test.go

@@ -167,6 +167,37 @@ func TestTomlConfig(t *testing.T) {
 	tutil.RequireNoError(t, rootCmd.Execute())
 }
 
+func TestInvalidCmds(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		Name        string
+		Args        []string
+		ErrContains string
+	}{
+		{
+			Name:        "no args",
+			Args:        []string{},
+			ErrContains: "no sub-command specified, see --help",
+		},
+		{
+			Name:        "invalid args",
+			Args:        []string{"invalid"},
+			ErrContains: "unknown command \"invalid\" for \"halo\"",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.Name, func(t *testing.T) {
+			t.Parallel()
+			rootCmd := libcmd.NewRootCmd("halo", "", New())
+			rootCmd.SetArgs(test.Args)
+			err := rootCmd.Execute()
+			require.Error(t, err)
+			require.Contains(t, err.Error(), test.ErrContains)
+		})
+	}
+}
+
 // slice is a convenience function for creating string slice literals.
 func slice(strs ...string) []string {
 	return strs

halo/cmd/testdata/TestCLIReference_halo.golden

@@ -1,6 +1,7 @@
 Halo is a consensus client implementation for the Omni Protocol
 
 Usage:
+  halo [flags]
   halo [command]
 
 Available Commands:

lib/cmd/cmd.go

@@ -20,32 +20,27 @@ import (
 	"github.com/spf13/viper"
 )
 
-// Main is the main entry point for the command line tool.
+// Main is the main entry point for the omni application binaries.
 // Usage:
 //
 //	   func main() {
 //		     libcmd.Main(appcmd.New())
 //	   }
 func Main(cmd *cobra.Command) {
-	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
-
-	SilenceErrUsage(cmd)
+	wrapRunCmd(cmd)
 
+	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	err := cmd.ExecuteContext(ctx)
-
 	cancel()
 
 	if err != nil {
-		log.Error(ctx, "!! Fatal error occurred, app died unexpectedly !!", err)
-
 		const errExitCode = 1
 		os.Exit(errExitCode) //nolint:revive // Deep exit is exactly the point of this helper function.
 	}
 }
 
 // NewRootCmd returns a new root cobra command that handles our command line tool.
 // It sets up the general viper config and binds the cobra flags to the viper flags.
-// It also silences the usage printing when commands error during "running".
 func NewRootCmd(appName string, appDescription string, subCmds ...*cobra.Command) *cobra.Command {
 	root := &cobra.Command{
 		Use:   appName,
@@ -54,6 +49,10 @@ func NewRootCmd(appName string, appDescription string, subCmds ...*cobra.Command
 		PersistentPreRunE: func(cmd *cobra.Command, _ []string) error {
 			return initializeConfig(appName, cmd)
 		},
+		RunE: func(*cobra.Command, []string) error {
+			// Callers should either add sub-commands or override RunE.
+			return errors.New("no sub-command specified, see --help")
+		},
 	}
 
 	root.AddCommand(subCmds...)
@@ -168,3 +167,34 @@ func bindFlags(cmd *cobra.Command, v *viper.Viper) error {
 
 	return lastErr
 }
+
+// wrapRunCmd wraps the "app run" command to custom fatal error log and silence cobra output.
+func wrapRunCmd(cmd *cobra.Command) {
+	runCmd := getRunCmd(cmd)
+	SilenceErrUsage(runCmd)
+	runFunc := runCmd.RunE
+	runCmd.RunE = func(cmd *cobra.Command, args []string) error {
+		if runFunc == nil {
+			return errors.New("run command RunE nil [BUG]")
+		}
+
+		err := runFunc(cmd, args)
+		if err != nil {
+			log.Error(cmd.Context(), "!! Fatal error occurred, app died !!", err)
+		}
+
+		return err
+	}
+}
+
+// getRunCmd returns the "run" subcommand of the given command or the command itself.
+func getRunCmd(cmd *cobra.Command) *cobra.Command {
+	const name = "run"
+	for _, sub := range cmd.Commands() {
+		if sub.Use == name {
+			return sub
+		}
+	}
+
+	return cmd
+}