Method _get_actions_usage_parts

Lib/argparse.py:410–514

Get usage parts with split index for optionals/positionals. Returns (parts, pos_start) where pos_start is the index in parts where positionals begin. This preserves mutually exclusive group formatting across the optionals/positionals boundary (gh-75949).

(self, actions, groups)

        return len(string) > 2

    def _get_actions_usage_parts(self, actions, groups):
        """Get usage parts with split index for optionals/positionals.

        Returns (parts, pos_start) where pos_start is the index in parts
        where positionals begin.
        This preserves mutually exclusive group formatting across the
        optionals/positionals boundary (gh-75949).
        """
        actions = [action for action in actions if action.help is not SUPPRESS]
        # group actions by mutually exclusive groups
        action_groups = dict.fromkeys(actions)
        for group in groups:
            for action in group._group_actions:
                if action in action_groups:
                    action_groups[action] = group
        # positional arguments keep their position
        positionals = []
        for action in actions:
            if not action.option_strings:
                group = action_groups.pop(action)
                if group:
                    group_actions = [
                        action2 for action2 in group._group_actions
                        if action2.option_strings and
                           action_groups.pop(action2, None)
                    ] + [action]
                    positionals.append((group.required, group_actions))
                else:
                    positionals.append((None, [action]))
        # the remaining optional arguments are sorted by the position of
        # the first option in the group
        optionals = []
        for action in actions:
            if action.option_strings and action in action_groups:
                group = action_groups.pop(action)
                if group:
                    group_actions = [action] + [
                        action2 for action2 in group._group_actions
                        if action2.option_strings and
                           action_groups.pop(action2, None)
                    ]
                    optionals.append((group.required, group_actions))
                else:
                    optionals.append((None, [action]))

        # collect all actions format strings
        parts = []
        t = self._theme
        pos_start = None
        for i, (required, group) in enumerate(optionals + positionals):
            start = len(parts)
            if i == len(optionals):
                pos_start = start
            in_group = len(group) > 1
            for action in group:
                # produce all arg strings
                if not action.option_strings:
                    default = self._get_default_metavar_for_positional(action)