[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.

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")