Properly handle empty args with new shellquote lib

Fixes #1454

internal/action/actions.go

@@ -667,11 +667,15 @@ func (h *BufPane) SaveAs() bool {
 		if !canceled {
 			// the filename might or might not be quoted, so unquote first then join the strings.
 			args, err := shellquote.Split(resp)
-			filename := strings.Join(args, " ")
 			if err != nil {
 				InfoBar.Error("Error parsing arguments: ", err)
 				return
 			}
+			if len(args) == 0 {
+				InfoBar.Error("No filename given")
+				return
+			}
+			filename := strings.Join(args, " ")
 			noPrompt := h.saveBufToFile(filename, "SaveAs")
 			if noPrompt {
 				h.completeAction("SaveAs")

internal/action/command.go

@@ -349,6 +349,9 @@ func (h *BufPane) OpenCmd(args []string) {
 			InfoBar.Error("Error parsing args ", err)
 			return
 		}
+		if len(args) == 0 {
+			return
+		}
 		filename = strings.Join(args, " ")
 
 		open := func() {
@@ -966,6 +969,10 @@ func (h *BufPane) HandleCommand(input string) {
 		return
 	}
 
+	if len(args) == 0 {
+		return
+	}
+
 	inputCmd := args[0]
 
 	if _, ok := commands[inputCmd]; !ok {

internal/action/terminal_supported.go

@@ -14,6 +14,9 @@ func RunTermEmulator(h *BufPane, input string, wait bool, getOutput bool, callba
 	if err != nil {
 		return err
 	}
+	if len(args) == 0 {
+		return nil
+	}
 
 	t := new(shell.Terminal)
 	t.Start(args, getOutput, wait, callback, userargs)

internal/shell/shell.go

@@ -2,6 +2,7 @@ package shell
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -36,6 +37,9 @@ func RunCommand(input string) (string, error) {
 	if err != nil {
 		return "", err
 	}
+	if len(args) == 0 {
+		return "", errors.New("No arguments")
+	}
 	inputCmd := args[0]
 
 	return ExecCommand(inputCmd, args[1:]...)
@@ -49,6 +53,9 @@ func RunBackgroundShell(input string) (func() string, error) {
 	if err != nil {
 		return nil, err
 	}
+	if len(args) == 0 {
+		return nil, errors.New("No arguments")
+	}
 	inputCmd := args[0]
 	return func() string {
 		output, err := RunCommand(input)
@@ -72,6 +79,9 @@ func RunInteractiveShell(input string, wait bool, getOutput bool) (string, error
 	if err != nil {
 		return "", err
 	}
+	if len(args) == 0 {
+		return "", errors.New("No arguments")
+	}
 	inputCmd := args[0]
 
 	// Shut down the screen because we're going to interact directly with the shell