Resolved merge conflict from merging master into plugin_functions

7 files changed, 188 insertions, 79 deletions

diff --git a/.appveyor.yml b/.appveyor.yml
index ad884315..91f45824 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -4,4 +4,4 @@ install:
 build: off
 
 test_script:
-  - python -m tox -e py35-win,py36-win
+  - python -m tox -e py35-win,py36-win,py37-win
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 764d0061..8fe148ae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,12 @@
-## 0.9.3 (July TBD, 2018)
+## 0.9.3 (July 12, 2018)
 * Bug Fixes
     * Fixed bug when StatementParser ``__init__()`` was called with ``terminators`` equal to ``None``
     * Fixed bug when ``Cmd.onecmd()`` was called with a raw ``str``
+* Enhancements
+    * Added ``--clear`` flag to ``history`` command that clears both the command and readline history.
+* Deletions
+    * The ``CmdResult`` helper class which was *deprecated* in the previous release has now been deleted
+        * It has been replaced by the improved ``CommandResult`` class
 
 ## 0.9.2 (June 28, 2018)
 * Bug Fixes
diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index 2cebe3f7..51f2f924 100644
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -371,19 +371,7 @@ class Cmd(cmd.Cmd):
             except AttributeError:
                 pass
 
-        # If persistent readline history is enabled, then read history from file and register to write to file at exit
-        if persistent_history_file and rl_type != RlType.NONE:
-            persistent_history_file = os.path.expanduser(persistent_history_file)
-            try:
-                readline.read_history_file(persistent_history_file)
-                # default history len is -1 (infinite), which may grow unruly
-                readline.set_history_length(persistent_history_length)
-            except FileNotFoundError:
-                pass
-            import atexit
-            atexit.register(readline.write_history_file, persistent_history_file)
-
-        # initialize plugin system
+		# initialize plugin system
         # needs to be done before we call __init__(0)
         self._initialize_plugin_system()
 
@@ -454,6 +442,37 @@ class Cmd(cmd.Cmd):
         # If this string is non-empty, then this warning message will print if a broken pipe error occurs while printing
         self.broken_pipe_warning = ''
 
+        # Check if history should persist
+        if persistent_history_file and rl_type != RlType.NONE:
+            persistent_history_file = os.path.expanduser(persistent_history_file)
+            read_err = False
+
+            try:
+                # First try to read any existing history file
+                readline.read_history_file(persistent_history_file)
+            except FileNotFoundError:
+                pass
+            except OSError as ex:
+                self.perror("readline cannot read persistent history file '{}': {}".format(persistent_history_file, ex),
+                            traceback_war=False)
+                read_err = True
+
+            if not read_err:
+                try:
+                    # Make sure readline is able to write the history file. Doing it this way is a more thorough check
+                    # than trying to open the file with write access since readline's underlying function needs to
+                    # create a temporary file in the same directory and may not have permission.
+                    readline.set_history_length(persistent_history_length)
+                    readline.write_history_file(persistent_history_file)
+                except OSError as ex:
+                    self.perror("readline cannot write persistent history file '{}': {}".
+                                format(persistent_history_file, ex), traceback_war=False)
+                else:
+                    # Set history file and register to save our history at exit
+                    import atexit
+                    self.persistent_history_file = persistent_history_file
+                    atexit.register(readline.write_history_file, self.persistent_history_file)
+
         # If a startup script is provided, then add it in the queue to load
         if startup_script is not None:
             startup_script = os.path.expanduser(startup_script)
@@ -617,7 +636,7 @@ class Cmd(cmd.Cmd):
                     try:
                         self.pipe_proc.stdin.write(msg_str.encode('utf-8', 'replace'))
                         self.pipe_proc.stdin.close()
-                    except (IOError, KeyboardInterrupt):
+                    except (OSError, KeyboardInterrupt):
                         pass
 
                     # Less doesn't respect ^C, but catches it for its own UI purposes (aborting search etc. inside less)
@@ -2634,8 +2653,9 @@ Usage:  Usage: unalias [-a] name [name ...]
                 try:
                     with open(filename) as f:
                         interp.runcode(f.read())
-                except IOError as e:
-                    self.perror(e)
+                except OSError as ex:
+                    error_msg = "Error opening script file '{}': {}".format(filename, ex)
+                    self.perror(error_msg, traceback_war=False)
 
             bridge = PyscriptBridge(self)
             self.pystate['run'] = run
@@ -2829,6 +2849,7 @@ Paths or arguments that contain spaces must be enclosed in quotes
     history_parser_group.add_argument('-s', '--script', action='store_true', help='script format; no separation lines')
     history_parser_group.add_argument('-o', '--output-file', metavar='FILE', help='output commands to a script file')
     history_parser_group.add_argument('-t', '--transcript', help='output commands and results to a transcript file')
+    history_parser_group.add_argument('-c', '--clear', action="store_true", help='clears all history')
     _history_arg_help = """empty               all history items
 a                   one history item by number
 a..b, a:b, a:, ..b  items by indices (inclusive)
@@ -2838,7 +2859,18 @@ a..b, a:b, a:, ..b  items by indices (inclusive)
 
     @with_argparser(history_parser)
     def do_history(self, args: argparse.Namespace) -> None:
-        """View, run, edit, and save previously entered commands."""
+        """View, run, edit, save, or clear previously entered commands."""
+
+        if args.clear:
+            # Clear command and readline history
+            self.history.clear()
+
+            if rl_type != RlType.NONE:
+                readline.clear_history()
+                if self.persistent_history_file:
+                    os.remove(self.persistent_history_file)
+            return
+
         # If an argument was supplied, then retrieve partial contents of the history
         cowardly_refuse_to_run = False
         if args.arg:
@@ -3044,25 +3076,30 @@ Script should contain one command per line, just like command would be typed in
         """
         # If arg is None or arg is an empty string this is an error
         if not arglist:
-            self.perror('load command requires a file path:', traceback_war=False)
+            self.perror('load command requires a file path', traceback_war=False)
             return
 
         file_path = arglist[0].strip()
         expanded_path = os.path.abspath(os.path.expanduser(file_path))
 
+        # Make sure the path exists and we can access it
+        if not os.path.exists(expanded_path):
+            self.perror("'{}' does not exist or cannot be accessed".format(expanded_path), traceback_war=False)
+            return
+
         # Make sure expanded_path points to a file
         if not os.path.isfile(expanded_path):
-            self.perror('{} does not exist or is not a file'.format(expanded_path), traceback_war=False)
+            self.perror("'{}' is not a file".format(expanded_path), traceback_war=False)
             return
 
         # Make sure the file is not empty
         if os.path.getsize(expanded_path) == 0:
-            self.perror('{} is empty'.format(expanded_path), traceback_war=False)
+            self.perror("'{}' is empty".format(expanded_path), traceback_war=False)
             return
 
         # Make sure the file is ASCII or UTF-8 encoded text
         if not utils.is_text_file(expanded_path):
-            self.perror('{} is not an ASCII or UTF-8 encoded text file'.format(expanded_path), traceback_war=False)
+            self.perror("'{}' is not an ASCII or UTF-8 encoded text file".format(expanded_path), traceback_war=False)
             return
 
         try:
@@ -3071,8 +3108,8 @@ Script should contain one command per line, just like command would be typed in
             # self._script_dir list when done.
             with open(expanded_path, encoding='utf-8') as target:
                 self.cmdqueue = target.read().splitlines() + ['eos'] + self.cmdqueue
-        except IOError as e:  # pragma: no cover
-            self.perror('Problem accessing script from {}:\n{}'.format(expanded_path, e))
+        except OSError as ex:  # pragma: no cover
+            self.perror("Problem accessing script from '{}': {}".format(expanded_path, ex))
             return
 
         self._script_dir.append(os.path.dirname(expanded_path))
@@ -3408,25 +3445,3 @@ class Statekeeper(object):
         if self.obj:
             for attrib in self.attribs:
                 setattr(self.obj, attrib, getattr(self, attrib))
-
-
-class CmdResult(utils.namedtuple_with_two_defaults('CmdResult', ['out', 'err', 'war'])):
-    """DEPRECATED: Derive a class to store results from a named tuple so we can tweak dunder methods for convenience.
-
-    This is provided as a convenience and an example for one possible way for end users to store results in
-    the self._last_result attribute of cmd2.Cmd class instances.  See the "python_scripting.py" example for how it can
-    be used to enable conditional control flow.
-
-    Named tuple attributes
-    ----------------------
-    out - this is intended to store normal output data from the command and can be of any type that makes sense
-    err: str - (optional) this is intended to store an error message and it being non-empty indicates there was an error
-                Defaults to an empty string
-    war: str - (optional) this is intended to store a warning message which isn't quite an error, but of note
-               Defaults to an empty string.
-
-    NOTE: Named tuples are immutable.  So the contents are there for access, not for modification.
-    """
-    def __bool__(self) -> bool:
-        """If err is an empty string, treat the result as a success; otherwise treat it as a failure."""
-        return not self.err
diff --git a/cmd2/utils.py b/cmd2/utils.py
index 11d48b78..d03e7f6f 100644
--- a/cmd2/utils.py
+++ b/cmd2/utils.py
@@ -61,22 +61,6 @@ def namedtuple_with_defaults(typename: str, field_names: Union[str, List[str]],
     return T
 
 
-def namedtuple_with_two_defaults(typename: str, field_names: Union[str, List[str]],
-                                 default_values: collections.Iterable=('', '')):
-    """Wrapper around namedtuple which lets you treat the last value as optional.
-
-    :param typename: str - type name for the Named tuple
-    :param field_names: List[str] or space-separated string of field names
-    :param default_values: (optional) 2-element tuple containing the default values for last 2 parameters in named tuple
-                            Defaults to an empty string for both of them
-    :return: namedtuple type
-    """
-    T = collections.namedtuple(typename, field_names)
-    # noinspection PyUnresolvedReferences
-    T.__new__.__defaults__ = default_values
-    return T
-
-
 def cast(current: Any, new: str) -> Any:
     """Tries to force a new value into the same type as the current when trying to set the value for a parameter.
 
@@ -143,7 +127,7 @@ def is_text_file(file_path: str) -> bool:
             # noinspection PyUnusedLocal
             if sum(1 for line in f) > 0:
                 valid_text_file = True
-    except IOError:  # pragma: no cover
+    except OSError:  # pragma: no cover
         pass
     except UnicodeDecodeError:
         # The file is not ASCII. Check if it is UTF-8.
@@ -153,7 +137,7 @@ def is_text_file(file_path: str) -> bool:
                 # noinspection PyUnusedLocal
                 if sum(1 for line in f) > 0:
                     valid_text_file = True
-        except IOError:  # pragma: no cover
+        except OSError:  # pragma: no cover
             pass
         except UnicodeDecodeError:
             # Not UTF-8
diff --git a/tests/conftest.py b/tests/conftest.py
index 90d45bd9..3f3b862e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -37,7 +37,7 @@ Documented commands (type help <topic>):
 alias               Define or display aliases
 edit                Edit a file in a text editor.
 help                List available commands with "help" or detailed help with "help cmd".
-history             View, run, edit, and save previously entered commands.
+history             View, run, edit, save, or clear previously entered commands.
 load                Runs commands in script file that is encoded as either ASCII or UTF-8 text.
 py                  Invoke python command, shell, or script
 pyscript            Runs a python script file inside the console
@@ -49,9 +49,9 @@ unalias             Unsets aliases
 """
 
 # Help text for the history command
-HELP_HISTORY = """usage: history [-h] [-r | -e | -s | -o FILE | -t TRANSCRIPT] [arg]
+HELP_HISTORY = """usage: history [-h] [-r | -e | -s | -o FILE | -t TRANSCRIPT | -c] [arg]
 
-View, run, edit, and save previously entered commands.
+View, run, edit, save, or clear previously entered commands.
 
 positional arguments:
   arg                   empty               all history items
@@ -69,6 +69,7 @@ optional arguments:
                         output commands to a script file
   -t TRANSCRIPT, --transcript TRANSCRIPT
                         output commands and results to a transcript file
+  -c, --clear           clears all history
 """
 
 # Output from the shortcuts command with default built-in shortcuts
diff --git a/tests/test_cmd2.py b/tests/test_cmd2.py
index b973fdf5..25d1db3f 100644
--- a/tests/test_cmd2.py
+++ b/tests/test_cmd2.py
@@ -231,7 +231,7 @@ 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("EXCEPTION of type 'FileNotFoundError' occurred with message:")
+    assert "Error opening script file" in err
 
 def test_pyscript_with_exception(base_app, capsys, request):
     test_dir = os.path.dirname(request.module.__file__)
@@ -426,7 +426,7 @@ def test_history_run_all_commands(base_app):
     out = run_cmd(base_app, 'history -r')
     # this should generate an error, but we don't currently have a way to
     # capture stderr in these tests. So we assume that if we got nothing on
-    # standard out, that the error occured because if the commaned executed
+    # standard out, that the error occurred because if the command executed
     # then we should have a list of shortcuts in our output
     assert out == []
 
@@ -435,6 +435,23 @@ def test_history_run_one_command(base_app):
     output = run_cmd(base_app, 'history -r 1')
     assert output == expected
 
+def test_history_clear(base_app):
+    # Add commands to history
+    run_cmd(base_app, 'help')
+    run_cmd(base_app, 'alias')
+
+    # Make sure history has items
+    out = run_cmd(base_app, 'history')
+    assert out
+
+    # Clear the history
+    run_cmd(base_app, 'history --clear')
+
+    # Make sure history is empty
+    out = run_cmd(base_app, 'history')
+    assert out == []
+
+
 def test_base_load(base_app, request):
     test_dir = os.path.dirname(request.module.__file__)
     filename = os.path.join(test_dir, 'script.txt')
@@ -457,8 +474,7 @@ def test_load_with_empty_args(base_app, capsys):
     out, err = capsys.readouterr()
 
     # The load command requires a file path argument, so we should get an error message
-    expected = normalize("""ERROR: load command requires a file path:\n""")
-    assert normalize(str(err)) == expected
+    assert "load command requires a file path" in str(err)
     assert base_app.cmdqueue == []
 
 
@@ -468,10 +484,18 @@ def test_load_with_nonexistent_file(base_app, capsys):
     out, err = capsys.readouterr()
 
     # The load command requires a path to an existing file
-    assert str(err).startswith("ERROR")
-    assert "does not exist or is not a file" in str(err)
+    assert "does not exist" in str(err)
     assert base_app.cmdqueue == []
 
+def test_load_with_directory(base_app, capsys, request):
+    test_dir = os.path.dirname(request.module.__file__)
+
+    # The way the load command works, we can't directly capture its stdout or stderr
+    run_cmd(base_app, 'load {}'.format(test_dir))
+    out, err = capsys.readouterr()
+
+    assert "is not a file" in str(err)
+    assert base_app.cmdqueue == []
 
 def test_load_with_empty_file(base_app, capsys, request):
     test_dir = os.path.dirname(request.module.__file__)
@@ -481,8 +505,7 @@ def test_load_with_empty_file(base_app, capsys, request):
     run_cmd(base_app, 'load {}'.format(filename))
     out, err = capsys.readouterr()
 
-    # The load command requires non-empty scripts files
-    assert str(err).startswith("ERROR")
+    # The load command requires non-empty script files
     assert "is empty" in str(err)
     assert base_app.cmdqueue == []
 
@@ -724,7 +747,7 @@ def test_pipe_to_shell(base_app, capsys):
     out, err = capsys.readouterr()
 
     # Unfortunately with the improved way of piping output to a subprocess, there isn't any good way of getting
-    # access to the output produced by that subprocess within a unit test, but we can verify that no error occured
+    # access to the output produced by that subprocess within a unit test, but we can verify that no error occurred
     assert not err
 
 def test_pipe_to_shell_error(base_app, capsys):
@@ -1225,7 +1248,7 @@ Other
 ================================================================================
 alias               Define or display aliases
 help                List available commands with "help" or detailed help with "help cmd".
-history             View, run, edit, and save previously entered commands.
+history             View, run, edit, save, or clear previously entered commands.
 load                Runs commands in script file that is encoded as either ASCII or UTF-8 text.
 py                  Invoke python command, shell, or script
 pyscript            Runs a python script file inside the console
@@ -1802,3 +1825,74 @@ def test_onecmd_raw_str_quit(base_app):
     assert stop
     assert out == ''
 
+
+@pytest.fixture(scope="session")
+def hist_file():
+    fd, filename = tempfile.mkstemp(prefix='hist_file', suffix='.txt')
+    os.close(fd)
+    yield filename
+    # teardown code
+    try:
+        os.remove(filename)
+    except FileNotFoundError:
+        pass
+
+def test_existing_history_file(hist_file, capsys):
+    import atexit
+    import readline
+
+    # Create the history file before making cmd2 app
+    with open(hist_file, 'w'):
+        pass
+
+    # Create a new cmd2 app
+    app = cmd2.Cmd(persistent_history_file=hist_file)
+    out, err = capsys.readouterr()
+
+    # Make sure there were no errors
+    assert err == ''
+
+    # Unregister the call to write_history_file that cmd2 did
+    atexit.unregister(readline.write_history_file)
+
+    # Remove created history file
+    os.remove(hist_file)
+
+
+def test_new_history_file(hist_file, capsys):
+    import atexit
+    import readline
+
+    # Remove any existing history file
+    try:
+        os.remove(hist_file)
+    except OSError:
+        pass
+
+    # Create a new cmd2 app
+    app = cmd2.Cmd(persistent_history_file=hist_file)
+    out, err = capsys.readouterr()
+
+    # Make sure there were no errors
+    assert err == ''
+
+    # Unregister the call to write_history_file that cmd2 did
+    atexit.unregister(readline.write_history_file)
+
+    # Remove created history file
+    os.remove(hist_file)
+
+def test_bad_history_file_path(capsys, request):
+    # Use a directory path as the history file
+    test_dir = os.path.dirname(request.module.__file__)
+
+    # Create a new cmd2 app
+    app = cmd2.Cmd(persistent_history_file=test_dir)
+    out, err = capsys.readouterr()
+
+    if sys.platform == 'win32':
+        # pyreadline masks the read exception. Therefore the bad path error occurs when trying to write the file.
+        assert 'readline cannot write' in err
+    else:
+        # GNU readline raises an exception upon trying to read the directory as a file
+        assert 'readline cannot read' in err
diff --git a/tox.ini b/tox.ini
index c7ccdeac..a5e91d46 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py34,py35,py36,py37,py35-win,py36-win
+envlist = py34,py35,py36,py37,py35-win,py36-win,py37-win
 
 [pytest]
 testpaths = tests
@@ -73,3 +73,13 @@ deps =
   wcwidth
 commands = py.test -v
 
+[testenv:py37-win]
+deps =
+  codecov
+  pyperclip
+  pyreadline
+  pytest
+  pytest-cov
+commands =
+  py.test {posargs} --cov
+  codecov