Fix flake8 issues

This commit contains a very large number of trivial changes in order to fix flake8 errors and warnings.  Predominantly these are whitespace changes.

Additionally, the build for Python 3.7 on TravisCI has been tweaked to fail if there are any flake8 errors using the following commandline:
* flake8 . --count --ignore=E252 --max-complexity=31 --max-line-length=127 --show-source --statistics
NOTE: In the future the max cyclomatic complexity should be lowered, but some improvements need to be made first.

One flake8 error is being ignored entirely:
* E252 missing whitespace around parameter equals
    * ignored because it doesn't correctly deal with default argument values after a type hint

A few flake8 errors are being selectively ignored in certain files:
* C901 fuction is too complex
    * ignored in argparse_completer.py because the complex code is an override of argparse complexity
* E302 expected 2 blank lines after ...
    * ignored in all unit test files for convenience
* F401 module imported but unused
    * ignored in cmd2/__init__.py because imports are for convenience of cmd2 developers and backwards compatibility
* F821 undefined name
    * ignored in cmd2 script files which are intended to run only within cmd2 applications via pyscript where "app" and "cmd" are defined

Author: tleonhardt

.travis.yml

@@ -46,8 +46,7 @@ before_script:
   # stop the build if there are Python syntax errors or undefined names
   # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
   if [[ $TOXENV == py37 ]]; then
-    flake8 . --count --exclude=./.*,./examples,./tests --select=E901,E999,F821,F822,F823 --show-source --statistics ;
-    flake8 . --count --exclude=./.* --exit-zero --max-complexity=10 --max-line-length=127 --statistics ;
+    flake8 . --count --ignore=E252 --max-complexity=31 --max-line-length=127 --show-source --statistics ;
   fi
 
 script:

cmd2/__init__.py

@@ -1,5 +1,6 @@
 #
 # -*- coding: utf-8 -*-
+# flake8: noqa F401
 """This simply imports certain things for backwards compatibility."""
 
 from pkg_resources import get_distribution, DistributionNotFound

cmd2/argcomplete_bridge.py

@@ -28,7 +28,6 @@
     from . import constants
     from . import utils
 
-
     def tokens_for_completion(line: str, endidx: int) -> Union[Tuple[List[str], List[str], int, int],
                                                                Tuple[None, None, None, None]]:
         """
@@ -254,7 +253,6 @@ def __call__(self, argument_parser, completer=None, always_complete_options=True
             argcomplete.debug_stream.flush()
             exit_method(0)
 
-
     def bash_complete(action, show_hint: bool = True):
         """Helper function to configure an argparse action to fall back to bash completion.
 

cmd2/argparse_completer.py

@@ -1,4 +1,7 @@
 # coding=utf-8
+# flake8: noqa C901
+# NOTE: Ignoreing flake8 cyclomatic complexity in this file because the complexity due to copy-and-paste overrides from
+#       argparse
 """
 AutoCompleter interprets the argparse.ArgumentParser internals to automatically
 generate the completion options for each argument.
@@ -595,15 +598,15 @@ def _format_completions(self, action, completions: List[Union[str, CompletionIte
             fill_width = int(term_size.columns * .6) - (token_width + 2)
             for item in completions:
                 entry = '{: <{token_width}}{: <{fill_width}}'.format(item, item.description,
-                                                                     token_width=token_width+2,
+                                                                     token_width=token_width + 2,
                                                                      fill_width=fill_width)
                 completions_with_desc.append(entry)
 
             try:
                 desc_header = action.desc_header
             except AttributeError:
                 desc_header = 'Description'
-            header = '\n{: <{token_width}}{}'.format(action.dest.upper(), desc_header, token_width=token_width+2)
+            header = '\n{: <{token_width}}{}'.format(action.dest.upper(), desc_header, token_width=token_width + 2)
 
             self._cmd2_app.completion_header = header
             self._cmd2_app.display_matches = completions_with_desc

cmd2/parsing.py

@@ -400,14 +400,14 @@ def parse(self, line: str) -> Statement:
 
         if terminator:
             if terminator == constants.LINE_FEED:
-                terminator_pos = len(tokens)+1
+                terminator_pos = len(tokens) + 1
 
             # everything before the first terminator is the command and the args
             (command, args) = self._command_and_args(tokens[:terminator_pos])
             arg_list = tokens[1:terminator_pos]
             # we will set the suffix later
             # remove all the tokens before and including the terminator
-            tokens = tokens[terminator_pos+1:]
+            tokens = tokens[terminator_pos + 1:]
         else:
             (testcommand, testargs) = self._command_and_args(tokens)
             if testcommand in self.multiline_commands:
@@ -427,7 +427,7 @@ def parse(self, line: str) -> Statement:
             # find the first pipe if it exists
             pipe_pos = tokens.index(constants.REDIRECTION_PIPE)
             # save everything after the first pipe as tokens
-            pipe_to = tokens[pipe_pos+1:]
+            pipe_to = tokens[pipe_pos + 1:]
 
             for pos, cur_token in enumerate(pipe_to):
                 unquoted_token = utils.strip_quotes(cur_token)

cmd2/pyscript_bridge.py

@@ -8,9 +8,8 @@
 """
 
 import argparse
-import functools
 import sys
-from typing import List, Callable, Optional
+from typing import List, Optional
 
 from .argparse_completer import _RangeAction, is_potential_flag
 from .utils import namedtuple_with_defaults, StdSim, quote_string_if_needed

cmd2/rl_utils.py

@@ -71,8 +71,9 @@ def enable_win_vt100(handle: HANDLE) -> bool:
         # Enable VT100 sequences for stdout and stderr
         STD_OUT_HANDLE = -11
         STD_ERROR_HANDLE = -12
-        vt100_support = (enable_win_vt100(readline.rl.console.GetStdHandle(STD_OUT_HANDLE)) and
-                         enable_win_vt100(readline.rl.console.GetStdHandle(STD_ERROR_HANDLE)))
+        vt100_stdout_support = enable_win_vt100(readline.rl.console.GetStdHandle(STD_OUT_HANDLE))
+        vt100_stderr_support = enable_win_vt100(readline.rl.console.GetStdHandle(STD_ERROR_HANDLE))
+        vt100_support = vt100_stdout_support and vt100_stderr_support
 
     ############################################################################################################
     # pyreadline is incomplete in terms of the Python readline API. Add the missing functions we need.

cmd2/transcript.py

@@ -77,7 +77,8 @@ def _test_transcript(self, fname: str, transcript):
                 try:
                     line = next(transcript)
                 except StopIteration as exc:
-                    msg = 'Transcript broke off while reading command beginning at line {} with\n{}'.format(line_num, command[0])
+                    msg = 'Transcript broke off while reading command beginning at line {} with\n{}'.format(line_num,
+                                                                                                            command[0])
                     raise StopIteration(msg) from exc
                 line_num += 1
             command = ''.join(command)
@@ -138,7 +139,7 @@ def _transform_transcript_expected(self, s: str) -> str:
                 # there is a slash, add everything we have found so far
                 # add stuff before the first slash as plain text
                 regex += re.escape(s[start:first_slash_pos])
-                start = first_slash_pos+1
+                start = first_slash_pos + 1
                 # and go find the next one
                 (regex, second_slash_pos, start) = self._escaped_find(regex, s, start, True)
                 if second_slash_pos > 0:
@@ -151,7 +152,7 @@ def _transform_transcript_expected(self, s: str) -> str:
                 else:
                     # No closing slash, we have to add the first slash,
                     # and the rest of the text
-                    regex += re.escape(s[start-1:])
+                    regex += re.escape(s[start - 1:])
                     break
         return regex
 
@@ -178,24 +179,24 @@ def _escaped_find(regex: str, s: str, start: int, in_regex: bool) -> Tuple[str,
                 break
             else:
                 # check if the slash is preceeded by a backslash
-                if s[pos-1:pos] == '\\':
+                if s[pos - 1:pos] == '\\':
                     # it is.
                     if in_regex:
                         # add everything up to the backslash as a
                         # regular expression
-                        regex += s[start:pos-1]
+                        regex += s[start:pos - 1]
                         # skip the backslash, and add the slash
                         regex += s[pos]
                     else:
                         # add everything up to the backslash as escaped
                         # plain text
-                        regex += re.escape(s[start:pos-1])
+                        regex += re.escape(s[start:pos - 1])
                         # and then add the slash as escaped
                         # plain text
                         regex += re.escape(s[pos])
                     # update start to show we have handled everything
                     # before it
-                    start = pos+1
+                    start = pos + 1
                     # and continue to look
                 else:
                     # slash is not escaped, this is what we are looking for

docs/conf.py

@@ -19,6 +19,9 @@
 """
 import os
 import sys
+
+from pkg_resources import get_distribution
+
 # Import for custom theme from Read the Docs
 import sphinx_rtd_theme
 
@@ -59,7 +62,6 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
-from pkg_resources import get_distribution
 # version will look like x.y.z
 version = get_distribution('cmd2').version
 # release will look like x.y

examples/alias_startup.py

@@ -7,6 +7,7 @@
 import os
 import cmd2
 
+
 class AliasAndStartup(cmd2.Cmd):
     """ Example cmd2 application where we create commands that just print the arguments they are called with."""