[cmd] Stop the surprising behavior of shell-splitting in cmd.New()

`cmd.New(programWithSpaces)` will now work for executables that have
spaces in the path. The only place where we relied on shell-splitting
was in openTextEditor, which now performs its own splitting.

Author: mislav

cmd/cmd.go

@@ -9,8 +9,6 @@ import (
 	"syscall"
 
 	"github.com/github/hub/ui"
-	"github.com/github/hub/utils"
-	"github.com/kballard/go-shellquote"
 )
 
 type Cmd struct {
@@ -123,14 +121,14 @@ func (cmd *Cmd) Exec() error {
 	return syscall.Exec(binary, args, os.Environ())
 }
 
-func New(cmd string) *Cmd {
-	cmds, err := shellquote.Split(cmd)
-	utils.Check(err)
-
-	name := cmds[0]
-	args := cmds[1:]
-
-	return &Cmd{Name: name, Args: args, Stdin: os.Stdin, Stdout: os.Stdout, Stderr: os.Stderr}
+func New(name string) *Cmd {
+	return &Cmd{
+		Name:   name,
+		Args:   []string{},
+		Stdin:  os.Stdin,
+		Stdout: os.Stdout,
+		Stderr: os.Stderr,
+	}
 }
 
 func NewWithArray(cmd []string) *Cmd {

cmd/cmd_test.go

@@ -8,9 +8,8 @@ import (
 
 func TestNew(t *testing.T) {
 	execCmd := New("vim --noplugin")
-	assert.Equal(t, "vim", execCmd.Name)
-	assert.Equal(t, 1, len(execCmd.Args))
-	assert.Equal(t, "--noplugin", execCmd.Args[0])
+	assert.Equal(t, "vim --noplugin", execCmd.Name)
+	assert.Equal(t, 0, len(execCmd.Args))
 }
 
 func TestWithArg(t *testing.T) {

github/editor.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/github/hub/cmd"
 	"github.com/github/hub/git"
+	"github.com/kballard/go-shellquote"
 )
 
 const Scissors = "------------------------ >8 ------------------------"
@@ -137,7 +138,11 @@ func (e *Editor) readContent() (content []byte, err error) {
 }
 
 func openTextEditor(program, file string) error {
-	editCmd := cmd.New(program)
+	programArgs, err := shellquote.Split(program)
+	if err != nil {
+		return err
+	}
+	editCmd := cmd.NewWithArray(programArgs)
 	r := regexp.MustCompile(`\b(?:[gm]?vim)(?:\.exe)?$`)
 	if r.MatchString(editCmd.Name) {
 		editCmd.WithArg("--cmd")