Further customization of argparse applying patch submitted to https://bugs.python.org/issue15112

Added additional tests - now at 100% coverage of pyscript_bridge.py
Still need handling of special action types: StoreTrue/False, store_const, count

Author: anselor

cmd2/argparse_completer.py

@@ -64,7 +64,8 @@ def my_completer(text: str, line: str, begidx: int, endidx:int, extra_param: str
 
 
 # imports copied from argparse to support our customized argparse functions
-from argparse import ZERO_OR_MORE, ONE_OR_MORE, ArgumentError, _
+from argparse import ZERO_OR_MORE, ONE_OR_MORE, ArgumentError, _, _get_action_name, SUPPRESS
+
 import re as _re
 
 
@@ -538,7 +539,10 @@ def _print_action_help(self, action: argparse.Action) -> None:
 
         prefix = '  {0: <{width}}    '.format(prefix, width=20)
         pref_len = len(prefix)
-        help_lines = action.help.splitlines()
+        if action.help is not None:
+            help_lines = action.help.splitlines()
+        else:
+            help_lines = ['']
         if len(help_lines) == 1:
             print('\nHint:\n{}{}\n'.format(prefix, help_lines[0]))
         else:
@@ -872,3 +876,259 @@ def _match_argument(self, action, arg_strings_pattern):
                                     'Expected between {} and {} arguments'.format(action.nargs_min, action.nargs_max))
 
         return super(ACArgumentParser, self)._match_argument(action, arg_strings_pattern)
+
+    def _parse_known_args(self, arg_strings, namespace):
+        # replace arg strings that are file references
+        if self.fromfile_prefix_chars is not None:
+            arg_strings = self._read_args_from_files(arg_strings)
+
+        # map all mutually exclusive arguments to the other arguments
+        # they can't occur with
+        action_conflicts = {}
+        for mutex_group in self._mutually_exclusive_groups:
+            group_actions = mutex_group._group_actions
+            for i, mutex_action in enumerate(mutex_group._group_actions):
+                conflicts = action_conflicts.setdefault(mutex_action, [])
+                conflicts.extend(group_actions[:i])
+                conflicts.extend(group_actions[i + 1:])
+
+        # find all option indices, and determine the arg_string_pattern
+        # which has an 'O' if there is an option at an index,
+        # an 'A' if there is an argument, or a '-' if there is a '--'
+        option_string_indices = {}
+        arg_string_pattern_parts = []
+        arg_strings_iter = iter(arg_strings)
+        for i, arg_string in enumerate(arg_strings_iter):
+
+            # all args after -- are non-options
+            if arg_string == '--':
+                arg_string_pattern_parts.append('-')
+                for arg_string in arg_strings_iter:
+                    arg_string_pattern_parts.append('A')
+
+            # otherwise, add the arg to the arg strings
+            # and note the index if it was an option
+            else:
+                option_tuple = self._parse_optional(arg_string)
+                if option_tuple is None:
+                    pattern = 'A'
+                else:
+                    option_string_indices[i] = option_tuple
+                    pattern = 'O'
+                arg_string_pattern_parts.append(pattern)
+
+        # join the pieces together to form the pattern
+        arg_strings_pattern = ''.join(arg_string_pattern_parts)
+
+        # converts arg strings to the appropriate and then takes the action
+        seen_actions = set()
+        seen_non_default_actions = set()
+
+        def take_action(action, argument_strings, option_string=None):
+            seen_actions.add(action)
+            argument_values = self._get_values(action, argument_strings)
+
+            # error if this argument is not allowed with other previously
+            # seen arguments, assuming that actions that use the default
+            # value don't really count as "present"
+            if argument_values is not action.default:
+                seen_non_default_actions.add(action)
+                for conflict_action in action_conflicts.get(action, []):
+                    if conflict_action in seen_non_default_actions:
+                        msg = _('not allowed with argument %s')
+                        action_name = _get_action_name(conflict_action)
+                        raise ArgumentError(action, msg % action_name)
+
+            # take the action if we didn't receive a SUPPRESS value
+            # (e.g. from a default)
+            if argument_values is not SUPPRESS:
+                action(self, namespace, argument_values, option_string)
+
+        # function to convert arg_strings into an optional action
+        def consume_optional(start_index):
+
+            # get the optional identified at this index
+            option_tuple = option_string_indices[start_index]
+            action, option_string, explicit_arg = option_tuple
+
+            # identify additional optionals in the same arg string
+            # (e.g. -xyz is the same as -x -y -z if no args are required)
+            match_argument = self._match_argument
+            action_tuples = []
+            while True:
+
+                # if we found no optional action, skip it
+                if action is None:
+                    extras.append(arg_strings[start_index])
+                    return start_index + 1
+
+                # if there is an explicit argument, try to match the
+                # optional's string arguments to only this
+                if explicit_arg is not None:
+                    arg_count = match_argument(action, 'A')
+
+                    # if the action is a single-dash option and takes no
+                    # arguments, try to parse more single-dash options out
+                    # of the tail of the option string
+                    chars = self.prefix_chars
+                    if arg_count == 0 and option_string[1] not in chars:
+                        action_tuples.append((action, [], option_string))
+                        char = option_string[0]
+                        option_string = char + explicit_arg[0]
+                        new_explicit_arg = explicit_arg[1:] or None
+                        optionals_map = self._option_string_actions
+                        if option_string in optionals_map:
+                            action = optionals_map[option_string]
+                            explicit_arg = new_explicit_arg
+                        else:
+                            msg = _('ignored explicit argument %r')
+                            raise ArgumentError(action, msg % explicit_arg)
+
+                    # if the action expect exactly one argument, we've
+                    # successfully matched the option; exit the loop
+                    elif arg_count == 1:
+                        stop = start_index + 1
+                        args = [explicit_arg]
+                        action_tuples.append((action, args, option_string))
+                        break
+
+                    # error if a double-dash option did not use the
+                    # explicit argument
+                    else:
+                        msg = _('ignored explicit argument %r')
+                        raise ArgumentError(action, msg % explicit_arg)
+
+                # if there is no explicit argument, try to match the
+                # optional's string arguments with the following strings
+                # if successful, exit the loop
+                else:
+                    start = start_index + 1
+                    selected_patterns = arg_strings_pattern[start:]
+                    arg_count = match_argument(action, selected_patterns)
+                    stop = start + arg_count
+                    args = arg_strings[start:stop]
+                    action_tuples.append((action, args, option_string))
+                    break
+
+            # add the Optional to the list and return the index at which
+            # the Optional's string args stopped
+            assert action_tuples
+            for action, args, option_string in action_tuples:
+                take_action(action, args, option_string)
+            return stop
+
+        # the list of Positionals left to be parsed; this is modified
+        # by consume_positionals()
+        positionals = self._get_positional_actions()
+
+        # function to convert arg_strings into positional actions
+        def consume_positionals(start_index):
+            # match as many Positionals as possible
+            match_partial = self._match_arguments_partial
+            selected_pattern = arg_strings_pattern[start_index:]
+            arg_counts = match_partial(positionals, selected_pattern)
+
+            ####################################################################
+            # Applied mixed.patch from https://bugs.python.org/issue15112
+            if 'O' in arg_strings_pattern[start_index:]:
+                # if there is an optional after this, remove
+                # 'empty' positionals from the current match
+
+                while len(arg_counts) > 1 and arg_counts[-1] == 0:
+                    arg_counts = arg_counts[:-1]
+            ####################################################################
+
+            # slice off the appropriate arg strings for each Positional
+            # and add the Positional and its args to the list
+            for action, arg_count in zip(positionals, arg_counts):
+                args = arg_strings[start_index: start_index + arg_count]
+                start_index += arg_count
+                take_action(action, args)
+
+            # slice off the Positionals that we just parsed and return the
+            # index at which the Positionals' string args stopped
+            positionals[:] = positionals[len(arg_counts):]
+            return start_index
+
+        # consume Positionals and Optionals alternately, until we have
+        # passed the last option string
+        extras = []
+        start_index = 0
+        if option_string_indices:
+            max_option_string_index = max(option_string_indices)
+        else:
+            max_option_string_index = -1
+        while start_index <= max_option_string_index:
+
+            # consume any Positionals preceding the next option
+            next_option_string_index = min([
+                index
+                for index in option_string_indices
+                if index >= start_index])
+            if start_index != next_option_string_index:
+                positionals_end_index = consume_positionals(start_index)
+
+                # only try to parse the next optional if we didn't consume
+                # the option string during the positionals parsing
+                if positionals_end_index > start_index:
+                    start_index = positionals_end_index
+                    continue
+                else:
+                    start_index = positionals_end_index
+
+            # if we consumed all the positionals we could and we're not
+            # at the index of an option string, there were extra arguments
+            if start_index not in option_string_indices:
+                strings = arg_strings[start_index:next_option_string_index]
+                extras.extend(strings)
+                start_index = next_option_string_index
+
+            # consume the next optional and any arguments for it
+            start_index = consume_optional(start_index)
+
+        # consume any positionals following the last Optional
+        stop_index = consume_positionals(start_index)
+
+        # if we didn't consume all the argument strings, there were extras
+        extras.extend(arg_strings[stop_index:])
+
+        # make sure all required actions were present and also convert
+        # action defaults which were not given as arguments
+        required_actions = []
+        for action in self._actions:
+            if action not in seen_actions:
+                if action.required:
+                    required_actions.append(_get_action_name(action))
+                else:
+                    # Convert action default now instead of doing it before
+                    # parsing arguments to avoid calling convert functions
+                    # twice (which may fail) if the argument was given, but
+                    # only if it was defined already in the namespace
+                    if (action.default is not None and
+                        isinstance(action.default, str) and
+                        hasattr(namespace, action.dest) and
+                        action.default is getattr(namespace, action.dest)):
+                        setattr(namespace, action.dest,
+                                self._get_value(action, action.default))
+
+        if required_actions:
+            self.error(_('the following arguments are required: %s') %
+                       ', '.join(required_actions))
+
+        # make sure all required groups had one option present
+        for group in self._mutually_exclusive_groups:
+            if group.required:
+                for action in group._group_actions:
+                    if action in seen_non_default_actions:
+                        break
+
+                # if no actions were used, report the error
+                else:
+                    names = [_get_action_name(action)
+                             for action in group._group_actions
+                             if action.help is not SUPPRESS]
+                    msg = _('one of the arguments %s is required')
+                    self.error(msg % ' '.join(names))
+
+        # return the updated namespace and the extra arguments
+        return namespace, extras

cmd2/pyscript_bridge.py

@@ -114,6 +114,7 @@ def traverse_parser(parser):
                                 process_flag(action, values)
                         else:
                             process_flag(action, self._args[action.dest])
+                    # TODO: StoreTrue/StoreFalse
                     else:
                         process_flag(action, self._args[action.dest])
 

tests/pyscript/media_movies_add2.py

@@ -0,0 +1 @@
+app.media.movies.add('My Movie', 'PG-13', actor=('Mark Hamill'), director=('George Lucas', 'J. J. Abrams'))

tests/test_pyscript.py

@@ -106,6 +106,8 @@ def test_pyscript_help(ps_app, capsys, request, command, pyscript_file):
     ('media movies list -r PG PG-13', 'media_movies_list7.py'),
     ('media movies add "My Movie" PG-13 --director "George Lucas" "J. J. Abrams"',
      'media_movies_add1.py'),
+    ('media movies add "My Movie" PG-13 --director "George Lucas" "J. J. Abrams" "Mark Hamill"',
+     'media_movies_add2.py'),
 ])
 def test_pyscript_out(ps_app, capsys, request, command, pyscript_file):
     test_dir = os.path.dirname(request.module.__file__)