Working on improving type hinting

Also:
- Refactored perror() to remove a rarely used optional argument which was unecessary

Author: tleonhardt

cmd2/__init__.py

@@ -1,4 +1,5 @@
 #
 # -*- coding: utf-8 -*-
+"""This simply imports certain things for backwards compatibility."""
 from .cmd2 import __version__, Cmd, CmdResult, Statement, EmptyStatement, categorize
 from .cmd2 import with_argument_list, with_argparser, with_argparser_and_unknown_args, with_category

cmd2/cmd2.py

@@ -10,7 +10,7 @@
 import argparse
 import functools
 import sys
-from typing import List, Tuple, Callable
+from typing import List, Callable
 
 # Python 3.4 require contextlib2 for temporarily redirecting stderr and stdout
 if sys.version_info < (3, 5):
@@ -298,4 +298,5 @@ def __dir__(self):
         return commands
 
     def __call__(self, args: str):
-        return _exec_cmd(self._cmd2_app, functools.partial(self._cmd2_app.onecmd_plus_hooks, args + '\n'), self.cmd_echo)
+        return _exec_cmd(self._cmd2_app, functools.partial(self._cmd2_app.onecmd_plus_hooks, args + '\n'),
+                         self.cmd_echo)

cmd2/pyscript_bridge.py

@@ -12,9 +12,11 @@
 import re
 import glob
 import unittest
+from typing import Tuple
 
 from . import utils
 
+
 class Cmd2TestCase(unittest.TestCase):
     """A unittest class used for transcript testing.
 
@@ -50,7 +52,7 @@ def runTest(self):  # was testall
             for (fname, transcript) in its:
                 self._test_transcript(fname, transcript)
 
-    def _test_transcript(self, fname, transcript):
+    def _test_transcript(self, fname: str, transcript):
         line_num = 0
         finished = False
         line = utils.strip_ansi(next(transcript))
@@ -103,7 +105,7 @@ def _test_transcript(self, fname, transcript):
                       fname, line_num, command, expected, result)
             self.assertTrue(re.match(expected, result, re.MULTILINE | re.DOTALL), message)
 
-    def _transform_transcript_expected(self, s):
+    def _transform_transcript_expected(self, s: str) -> str:
         """Parse the string with slashed regexes into a valid regex.
 
         Given a string like:
@@ -151,7 +153,7 @@ def _transform_transcript_expected(self, s):
         return regex
 
     @staticmethod
-    def _escaped_find(regex, s, start, in_regex):
+    def _escaped_find(regex: str, s: str, start: int, in_regex: bool) -> Tuple[str, int, int]:
         """Find the next slash in {s} after {start} that is not preceded by a backslash.
 
         If we find an escaped slash, add everything up to and including it to regex,
@@ -162,7 +164,6 @@ def _escaped_find(regex, s, start, in_regex):
         {in_regex} specifies whether we are currently searching in a regex, we behave
         differently if we are or if we aren't.
         """
-
         while True:
             pos = s.find('/', start)
             if pos == -1:
@@ -211,14 +212,11 @@ class OutputTrap(object):
     def __init__(self):
         self.contents = ''
 
-    def write(self, txt):
-        """Add text to the internal contents.
-
-        :param txt: str
-        """
+    def write(self, txt: str):
+        """Add text to the internal contents."""
         self.contents += txt
 
-    def read(self):
+    def read(self) -> str:
         """Read from the internal contents and then clear them out.
 
         :return: str - text from the internal contents

cmd2/transcript.py

@@ -8,6 +8,7 @@
 
 from . import constants
 
+
 def strip_ansi(text: str) -> str:
     """Strip ANSI escape codes from a string.
 
@@ -58,6 +59,7 @@ def namedtuple_with_defaults(typename, field_names, default_values=()):
     T.__new__.__defaults__ = tuple(prototype)
     return T
 
+
 def namedtuple_with_two_defaults(typename, field_names, default_values=('', '')):
     """Wrapper around namedtuple which lets you treat the last value as optional.
 
@@ -72,6 +74,7 @@ def namedtuple_with_two_defaults(typename, field_names, default_values=('', ''))
     T.__new__.__defaults__ = default_values
     return T
 
+
 def cast(current, new):
     """Tries to force a new value into the same type as the current when trying to set the value for a parameter.
 
@@ -101,6 +104,7 @@ def cast(current, new):
     print("Problem setting parameter (now %s) to %s; incorrect type?" % (current, new))
     return current
 
+
 def which(editor: str) -> Optional[str]:
     """Find the full path of a given editor.
 
@@ -118,7 +122,8 @@ def which(editor: str) -> Optional[str]:
         editor_path = None
     return editor_path
 
-def is_text_file(file_path):
+
+def is_text_file(file_path: str) -> bool:
     """Returns if a file contains only ASCII or UTF-8 encoded text
 
     :param file_path: path to the file being checked

cmd2/utils.py

@@ -230,7 +230,7 @@ def test_pyscript_with_nonexist_file(base_app, capsys):
     python_script = 'does_not_exist.py'
     run_cmd(base_app, "pyscript {}".format(python_script))
     out, err = capsys.readouterr()
-    assert err.startswith('ERROR: [Errno 2] No such file or directory:')
+    assert err.startswith("EXCEPTION of type 'FileNotFoundError' occurred with message:")
 
 def test_pyscript_with_exception(base_app, capsys, request):
     test_dir = os.path.dirname(request.module.__file__)