Use an object-oriented style for the dir stack so we maintain its inv…

…ariants.

Also reset allowed failures for 'builtins2', now that 'dirs' works.

core/builtin.py

@@ -480,11 +480,8 @@ def Cd(argv, mem, dir_stack):
    util.error("cd %r: %s", dest_dir, os.strerror(e.errno))
    return 1

  # Set $PWD.
  state.SetGlobalString(mem, 'PWD', dest_dir)

  # Truncate the directory stack.
  dir_stack[:] = [dest_dir]
  state.SetGlobalString(mem, 'PWD', dest_dir)  # Set $PWD.
  dir_stack.Reset()  # for pushd/popd/dirs

  return 0

@@ -493,19 +490,19 @@ def Cd(argv, mem, dir_stack):
WITHOUT_PREFIX = 2
SINGLE_LINE = 3

def _PrintDirStack(dir_stack, mode):
  to_print = list(reversed(dir_stack))
def _PrintDirStack(dir_stack, style):
  """Helper for 'dirs'."""

  if mode == WITH_PREFIX:
    for i, entry in enumerate(to_print):
  if style == WITH_PREFIX:
    for i, entry in enumerate(dir_stack.Iter()):
      print('%2d  %s' % (i, entry))

  elif mode == WITHOUT_PREFIX:
    for entry in to_print:
  elif style == WITHOUT_PREFIX:
    for entry in dir_stack.Iter():
      print(entry)

  elif mode == SINGLE_LINE:
    print(' '.join(to_print))
  elif style == SINGLE_LINE:
    print(' '.join(dir_stack.Iter()))

  sys.stdout.flush()

@@ -526,17 +523,17 @@ def Pushd(argv, dir_stack):
    util.error("pushd: %r: %s", dest_dir, os.strerror(e.errno))
    return 1

  dir_stack.append(dest_dir)
  dir_stack.Push(dest_dir)
  _PrintDirStack(dir_stack, SINGLE_LINE)
  return 0


def Popd(argv, dir_stack):
  if len(dir_stack) <= 1:
  dest_dir = dir_stack.Pop()
  if dest_dir is None:
    util.error('popd: directory stack is empty')
    return 1

  dest_dir = dir_stack.pop()
  try:
    os.chdir(dest_dir)
  except OSError as e:
@@ -559,8 +556,7 @@ def Dirs(argv, dir_stack):
    util.warn('*** dirs -l not implemented ***')
  # Following bash behavior
  if arg.c:
    # This initialization is also in the executor.
    dir_stack[:] = [os.getcwd()]
    dir_stack.Reset()
  elif arg.v:
    _PrintDirStack(dir_stack, WITH_PREFIX)
  elif arg.p:

core/cmd_exec.py

@@ -124,7 +124,7 @@ def __init__(self, mem, status_lines, funcs, completion, comp_lookup,

    self.traps = {}
    self.fd_state = process.FdState()
    self.dir_stack = [os.getcwd()]
    self.dir_stack = state.DirStack()

    # TODO: Pass these in from main()
    self.aliases = {}  # alias name -> string

core/state.py

@@ -194,6 +194,29 @@ def SetArgv(self, argv):
    self.num_shifted = 0


class DirStack(object):
  """For pushd/popd/dirs."""

  def __init__(self):
    self.stack = []
    self.Reset()
    
  def Reset(self):
    self.stack[:] = [os.getcwd()]

  def Push(self, entry):
    self.stack.append(entry)

  def Pop(self):
    if len(self.stack) <= 1:
      return None
    return self.stack.pop()

  def Iter(self):
    """Iterate in reverse order."""
    return reversed(self.stack)


class Mem(object):
  """For storing variables.

test/spec.sh

@@ -258,7 +258,7 @@ builtins() {

builtins2() {
  # 4 tests for 'dirs' fail.
  sh-spec spec/builtins2.test.sh --osh-failures-allowed 4 \
  sh-spec spec/builtins2.test.sh \
    ${REF_SHELLS[@]} $ZSH $OSH "$@"
}