Added Cmd2ShlexError

Author: kmvanbrunt

cmd2/cmd2.py

@@ -50,7 +50,7 @@
 from .argparse_custom import CompletionItem, DEFAULT_ARGUMENT_PARSER
 from .clipboard import can_clip, get_paste_buffer, write_to_paste_buffer
 from .decorators import with_argparser
-from .exceptions import Cmd2ArgparseException, EmbeddedConsoleExit, EmptyStatement
+from .exceptions import Cmd2ArgparseError, Cmd2ShlexError, EmbeddedConsoleExit, EmptyStatement
 from .history import History, HistoryItem
 from .parsing import StatementParser, Statement, Macro, MacroArg, shlex_split
 from .rl_utils import rl_type, RlType, rl_get_point, rl_set_prompt, vt100_support, rl_make_safe_prompt, rl_warning
@@ -1599,9 +1599,8 @@ def onecmd_plus_hooks(self, line: str, *, add_to_history: bool = True, py_bridge
         stop = False
         try:
             statement = self._input_line_to_statement(line)
-        except (EmptyStatement, ValueError) as ex:
-            if isinstance(ex, ValueError):
-                # Since shlex.split() failed on syntax, let user know what's going on
+        except (EmptyStatement, Cmd2ShlexError) as ex:
+            if isinstance(ex, Cmd2ShlexError):
                 self.perror("Invalid syntax: {}".format(ex))
             return self._run_cmdfinalization_hooks(stop, None)
 
@@ -1683,7 +1682,7 @@ def onecmd_plus_hooks(self, line: str, *, add_to_history: bool = True, py_bridge
                         # Stop saving command's stdout before command finalization hooks run
                         self.stdout.pause_storage = True
 
-        except (Cmd2ArgparseException, EmptyStatement):
+        except (Cmd2ArgparseError, EmptyStatement):
             # Don't do anything, but do allow command finalization hooks to run
             pass
         except Exception as ex:
@@ -1743,6 +1742,8 @@ def _complete_statement(self, line: str) -> Statement:
 
         :param line: the line being parsed
         :return: the completed Statement
+        :raises: Cmd2ShlexError if a shlex error occurs (e.g. No closing quotation)
+                 EmptyStatement when the resulting Statement is blank
         """
         while True:
             try:
@@ -1754,7 +1755,7 @@ def _complete_statement(self, line: str) -> Statement:
                     # it's not a multiline command, but we parsed it ok
                     # so we are done
                     break
-            except ValueError:
+            except Cmd2ShlexError:
                 # we have unclosed quotation marks, lets parse only the command
                 # and see if it's a multiline
                 statement = self.statement_parser.parse_command_only(line)
@@ -1791,7 +1792,7 @@ def _complete_statement(self, line: str) -> Statement:
                 self._at_continuation_prompt = False
 
         if not statement.command:
-            raise EmptyStatement()
+            raise EmptyStatement
         return statement
 
     def _input_line_to_statement(self, line: str) -> Statement:
@@ -1800,6 +1801,8 @@ def _input_line_to_statement(self, line: str) -> Statement:
 
         :param line: the line being parsed
         :return: parsed command line as a Statement
+        :raises: Cmd2ShlexError if a shlex error occurs (e.g. No closing quotation)
+                 EmptyStatement when the resulting Statement is blank
         """
         used_macros = []
         orig_line = None
@@ -1818,7 +1821,7 @@ def _input_line_to_statement(self, line: str) -> Statement:
                 used_macros.append(statement.command)
                 line = self._resolve_macro(statement)
                 if line is None:
-                    raise EmptyStatement()
+                    raise EmptyStatement
             else:
                 break
 

cmd2/decorators.py

@@ -4,7 +4,7 @@
 from typing import Callable, List, Optional, Union
 
 from . import constants
-from .exceptions import Cmd2ArgparseException
+from .exceptions import Cmd2ArgparseError
 from .parsing import Statement
 
 
@@ -145,7 +145,7 @@ def cmd_wrapper(cmd2_app, statement: Union[Statement, str]):
             try:
                 args, unknown = parser.parse_known_args(parsed_arglist, namespace)
             except SystemExit:
-                raise Cmd2ArgparseException
+                raise Cmd2ArgparseError
             else:
                 setattr(args, '__statement__', statement)
                 return func(cmd2_app, args, unknown)
@@ -217,7 +217,7 @@ def cmd_wrapper(cmd2_app, statement: Union[Statement, str]):
             try:
                 args = parser.parse_args(parsed_arglist, namespace)
             except SystemExit:
-                raise Cmd2ArgparseException
+                raise Cmd2ArgparseError
             else:
                 setattr(args, '__statement__', statement)
                 return func(cmd2_app, args)

cmd2/exceptions.py

@@ -2,8 +2,17 @@
 """Custom exceptions for cmd2.  These are NOT part of the public API and are intended for internal use only."""
 
 
-class Cmd2ArgparseException(Exception):
-    """Custom exception class for when an argparse-decorated command has an error parsing its arguments"""
+class Cmd2ArgparseError(Exception):
+    """
+    Custom exception class for when a command has an error parsing its arguments.
+    This can be raised by argparse decorators or the command functions themselves.
+    The main use of this exception is to tell cmd2 not to run Postcommand hooks.
+    """
+    pass
+
+
+class Cmd2ShlexError(Exception):
+    """Raised when shlex fails to parse a command line string in StatementParser"""
     pass
 
 

cmd2/parsing.py

@@ -10,6 +10,7 @@
 
 from . import constants
 from . import utils
+from .exceptions import Cmd2ShlexError
 
 
 def shlex_split(str_to_split: str) -> List[str]:
@@ -330,7 +331,7 @@ def tokenize(self, line: str) -> List[str]:
 
         :param line: the command line being lexed
         :return: A list of tokens
-        :raises ValueError: if there are unclosed quotation marks
+        :raises: Cmd2ShlexError if a shlex error occurs (e.g. No closing quotation)
         """
 
         # expand shortcuts and aliases
@@ -341,7 +342,10 @@ def tokenize(self, line: str) -> List[str]:
             return []
 
         # split on whitespace
-        tokens = shlex_split(line)
+        try:
+            tokens = shlex_split(line)
+        except ValueError as ex:
+            raise Cmd2ShlexError(ex)
 
         # custom lexing
         tokens = self.split_on_punctuation(tokens)
@@ -355,7 +359,7 @@ def parse(self, line: str) -> Statement:
 
         :param line: the command line being parsed
         :return: a new :class:`~cmd2.Statement` object
-        :raises ValueError: if there are unclosed quotation marks
+        :raises: Cmd2ShlexError if a shlex error occurs (e.g. No closing quotation)
         """
 
         # handle the special case/hardcoded terminator of a blank line
@@ -518,8 +522,6 @@ def parse_command_only(self, rawinput: str) -> Statement:
         :param rawinput: the command line as entered by the user
         :return: a new :class:`~cmd2.Statement` object
         """
-        line = rawinput
-
         # expand shortcuts and aliases
         line = self._expand(rawinput)
 

tests/test_parsing.py

@@ -96,7 +96,7 @@ def test_tokenize(parser, line, tokens):
     assert tokens_to_test == tokens
 
 def test_tokenize_unclosed_quotes(parser):
-    with pytest.raises(ValueError):
+    with pytest.raises(exceptions.Cmd2ShlexError):
         _ = parser.tokenize('command with "unclosed quotes')
 
 @pytest.mark.parametrize('tokens,command,args', [
@@ -583,7 +583,7 @@ def test_parse_redirect_to_unicode_filename(parser):
     assert statement.output_to == 'café'
 
 def test_parse_unclosed_quotes(parser):
-    with pytest.raises(ValueError):
+    with pytest.raises(exceptions.Cmd2ShlexError):
         _ = parser.tokenize("command with 'unclosed quotes")
 
 def test_empty_statement_raises_exception():