diff options
| -rw-r--r-- | discord/ext/commands/help.py | 81 |
1 files changed, 52 insertions, 29 deletions
diff --git a/discord/ext/commands/help.py b/discord/ext/commands/help.py index 19c762e8..7a3b7e23 100644 --- a/discord/ext/commands/help.py +++ b/discord/ext/commands/help.py @@ -25,6 +25,7 @@ DEALINGS IN THE SOFTWARE. """ import itertools +import copy import functools import inspect import re @@ -166,15 +167,23 @@ def _not_overriden(f): class _HelpCommandImpl(Command): def __init__(self, inject, *args, **kwargs): - super().__init__(*args, **kwargs) + super().__init__(inject.command_callback, *args, **kwargs) + self._original = inject self._injected = inject - on_error = inject.on_help_command_error - try: - on_error.__help_command_not_overriden__ - except AttributeError: - # overridden - self.on_error = on_error + async def prepare(self, ctx): + self._injected = injected = self._original.copy() + injected.context = ctx + self.callback = injected.command_callback + + on_error = injected.on_help_command_error + if not hasattr(on_error, '__help_command_not_overriden__'): + if self.cog is not None: + self.on_error = self._on_error_cog_implementation + else: + self.on_error = on_error + + await super().prepare(ctx) async def _parse_arguments(self, ctx): # Make the parser think we don't have a cog so it doesn't @@ -221,13 +230,6 @@ class _HelpCommandImpl(Command): cog.walk_commands = wrapped_walk_commands self.cog = cog - on_error = self._injected.on_help_command_error - try: - on_error.__help_command_not_overriden__ - except AttributeError: - # overridden so let's swap it with our cog specific implementation - self.on_error = self._on_error_cog_implementation - def _eject_cog(self): if self.cog is None: return @@ -238,16 +240,18 @@ class _HelpCommandImpl(Command): cog.walk_commands = cog.walk_commands.__wrapped__ self.cog = None - on_error = self._injected.on_help_command_error - try: - on_error.__help_command_not_overriden__ - except AttributeError: - # overridden so let's swap it with our cog specific implementation - self.on_error = self._on_error_cog_implementation - class HelpCommand: r"""The base implementation for help command formatting. + .. note:: + + Internally instances of this class are deep copied every time + the command itself is invoked to prevent a race condition + mentioned in :issue:`2123`. + + This means that relying on the state of this class to be + the same between command invocations would not as expected. + Attributes ------------ context: Optional[:class:`Context`] @@ -275,6 +279,25 @@ class HelpCommand: MENTION_PATTERN = re.compile('|'.join(MENTION_TRANSFORMS.keys())) + def __new__(cls, *args, **kwargs): + # To prevent race conditions of a single instance while also allowing + # for settings to be passed the original arguments passed must be assigned + # to allow for easier copies (which will be made when the help command is actually called) + # see issue 2123 + self = super().__new__(cls) + + # Shallow copies cannot be used in this case since it is not unusual to pass + # instances that need state, e.g. Paginator or what have you into the function + # The keys can be safely copied as-is since they're 99.99% certain of being + # string keys + deepcopy = copy.deepcopy + self.__original_kwargs__ = { + k: deepcopy(v) + for k, v in kwargs.items() + } + self.__original_args__ = deepcopy(args) + return self + def __init__(self, **options): self.show_hidden = options.pop('show_hidden', False) self.verify_checks = options.pop('verify_checks', True) @@ -284,8 +307,13 @@ class HelpCommand: self.context = None self._command_impl = None + def copy(self): + obj = self.__class__(*self.__original_args__, **self.__original_kwargs__) + obj._command_impl = self._command_impl + return obj + def _add_to_bot(self, bot): - command = _HelpCommandImpl(self, self.command_callback, **self.command_attrs) + command = _HelpCommandImpl(self, **self.command_attrs) bot.add_command(command) self._command_impl = command @@ -707,12 +735,7 @@ class HelpCommand: some state in your subclass before the command does its processing then this would be the place to do it. - The default implementation sets :attr:`context`. - - .. warning:: - - If you override this method, be sure to call ``super()`` - so the help command can be set up. + The default implementation does nothing. .. note:: @@ -726,7 +749,7 @@ class HelpCommand: command: Optional[:class:`str`] The argument passed to the help command. """ - self.context = ctx + pass async def command_callback(self, ctx, *, command=None): """|coro| |