Implement cd -P and -L; respect -- (#109)

-P uses os.path.realpath().

core/builtin.py

@@ -322,7 +322,7 @@ def Jobs(argv, job_state):
# - If there are more words than names, the remaining words and their
# intervening delimiters are assigned to the last name.
# - If there are fewer words read from the input stream than names, the
# remaining names are assigned empty values. 
# remaining names are assigned empty values.
# - The characters in the value of the IFS variable are used to split the line
# into words using the same rules the shell uses for expansion (described
# above in Word Splitting).
@@ -484,11 +484,16 @@ def Shift(argv, mem):

  return mem.Shift(n)

CD_SPEC = _Register('cd')
CD_SPEC.ShortFlag('-L')
CD_SPEC.ShortFlag('-P')

def Cd(argv, mem, dir_stack):
  # TODO: Parse flags, error checking, etc.
  arg, i = CD_SPEC.Parse(argv)
  # TODO: error checking, etc.

  try:
    dest_dir = argv[0]
    dest_dir = argv[i]
  except IndexError:
    val = mem.GetVar('HOME')
    if val.tag == value_e.Undef:
@@ -526,7 +531,13 @@ def Cd(argv, mem, dir_stack):
    util.error("cd %r: %s", dest_dir, os.strerror(e.errno))
    return 1

  state.SetGlobalString(mem, 'PWD', dest_dir)  # Set $PWD.
  # Set $PWD.
  # `-L` is the default behavior; no need to check it
  # TODO: ensure that if multiple flags are provided, the *last* one overrides
  # the others
  pwd = os.path.realpath(dest_dir) if arg.P else dest_dir
  state.SetGlobalString(mem, 'PWD', pwd)

  dir_stack.Reset()  # for pushd/popd/dirs

  return 0
@@ -830,7 +841,7 @@ def _ResolveNames(names, funcs, path_val):
    results.append(kind)

  return results
    


COMMAND_SPEC = _Register('command')
COMMAND_SPEC.ShortFlag('-v')
@@ -1088,7 +1099,7 @@ def Umask(argv):
    # NOTE: dash disables interrupts around the two umask() calls, but that
    # shouldn't be a concern for us.  Signal handlers won't call umask().
    mask = os.umask(0)
    os.umask(mask)  # 
    os.umask(mask)  #
    print('0%03o' % mask)  # octal format
    return 0

spec/builtins.test.sh

@@ -54,6 +54,59 @@ cd-nonexistent
status=0
## END

### cd permits double bare dash
cd -- /
echo $PWD
# stdout: /

### cd to non-symlink with `-P`
targ=$TMP/cd-symtarget
lnk=$TMP/cd-symlink
mkdir -p $targ
ln -s $targ $lnk
cd -P $targ
test $PWD = "$TMP/cd-symtarget" && echo OK
cd $TMP
rmdir $targ
rm $lnk
# stdout: OK

### cd to symlink default behavior
targ=$TMP/cd-symtarget
lnk=$TMP/cd-symlink
mkdir -p $targ
ln -s $targ $lnk
cd $lnk
test $PWD = "$TMP/cd-symlink" && echo OK
cd $TMP
rmdir $targ
rm $lnk
# stdout: OK

### cd to symlink with `-L`
targ=$TMP/cd-symtarget
lnk=$TMP/cd-symlink
mkdir -p $targ
ln -s $targ $lnk
cd -L $lnk
test $PWD = "$TMP/cd-symlink" && echo OK
cd $TMP
rmdir $targ
rm $lnk
# stdout: OK

### cd to symlink with `-P`
targ=$TMP/cd-symtarget
lnk=$TMP/cd-symlink
mkdir -p $targ
ln -s $targ $lnk
cd -P $lnk
test $PWD = "$TMP/cd-symtarget" && echo OK
cd $TMP
rmdir $targ
rm $lnk
# stdout: OK

### pushd/popd
set -o errexit
cd /