prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  Forbid setting user and chat data attributes
  Inevitably users will attempt to do `context.user_data = {'my': 'dict'}` or `context.chat_data = whatever`. This will lead to confusing behaviour.
  
  I propose making those fields properties without a setter, which will more helpfully error. Depending on how far we want to go, we can also suggest the user to use `update(other_dict)` if they attempt to set the field.
  
  See https://t.me/pythontelegrambotgroup/222138 onwards.
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `telegram/ext/callbackcontext.py`
  Content:
  ```
  1 #!/usr/bin/env python
  2 #
  3 # A library that provides a Python interface to the Telegram Bot API
  4 # Copyright (C) 2015-2018
  5 # Leandro Toledo de Souza <devs@python-telegram-bot.org>
  6 #
  7 # This program is free software: you can redistribute it and/or modify
  8 # it under the terms of the GNU Lesser Public License as published by
  9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU Lesser Public License for more details.
  16 #
  17 # You should have received a copy of the GNU Lesser Public License
  18 # along with this program.  If not, see [http://www.gnu.org/licenses/].
  19 """This module contains the CallbackContext class."""
  20 
  21 from telegram import Update
  22 
  23 
  24 class CallbackContext(object):
  25     """
  26     This is a context object passed to the callback called by :class:`telegram.ext.Handler`
  27     or by the :class:`telegram.ext.Dispatcher` in an error handler added by
  28     :attr:`telegram.ext.Dispatcher.add_error_handler` or to the callback of a
  29     :class:`telegram.ext.Job`.
  30 
  31     Note:
  32         :class:`telegram.ext.Dispatcher` will create a single context for an entire update. This
  33         means that if you got 2 handlers in different groups and they both get called, they will
  34         get passed the same `CallbackContext` object (of course with proper attributes like
  35         `.matches` differing). This allows you to add custom attributes in a lower handler group
  36         callback, and then subsequently access those attributes in a higher handler group callback.
  37         Note that the attributes on `CallbackContext` might change in the future, so make sure to
  38         use a fairly unique name for the attributes.
  39 
  40     Warning:
  41          Do not combine custom attributes and @run_async. Due to how @run_async works, it will
  42          almost certainly execute the callbacks for an update out of order, and the attributes
  43          that you think you added will not be present.
  44 
  45     Attributes:
  46         chat_data (:obj:`dict`, optional): A dict that can be used to keep any data in. For each
  47             update from the same chat it will be the same ``dict``.
  48         user_data (:obj:`dict`, optional): A dict that can be used to keep any data in. For each
  49             update from the same user it will be the same ``dict``.
  50         matches (List[:obj:`re match object`], optional): If the associated update originated from
  51             a regex-supported handler or had a :class:`Filters.regex`, this will contain a list of
  52             match objects for every pattern where ``re.search(pattern, string)`` returned a match.
  53             Note that filters short circuit, so combined regex filters will not always
  54             be evaluated.
  55         args (List[:obj:`str`], optional): Arguments passed to a command if the associated update
  56             is handled by :class:`telegram.ext.CommandHandler`, :class:`telegram.ext.PrefixHandler`
  57             or :class:`telegram.ext.StringCommandHandler`. It contains a list of the words in the
  58             text after the command, using any whitespace string as a delimiter.
  59         error (:class:`telegram.TelegramError`, optional): The Telegram error that was raised.
  60             Only present when passed to a error handler registered with
  61             :attr:`telegram.ext.Dispatcher.add_error_handler`.
  62         job (:class:`telegram.ext.Job`): The job that that originated this callback.
  63             Only present when passed to the callback of :class:`telegram.ext.Job`.
  64 
  65     """
  66 
  67     def __init__(self, dispatcher):
  68         """
  69         Args:
  70             dispatcher (:class:`telegram.ext.Dispatcher`):
  71         """
  72         if not dispatcher.use_context:
  73             raise ValueError('CallbackContext should not be used with a non context aware '
  74                              'dispatcher!')
  75         self._dispatcher = dispatcher
  76         self.chat_data = None
  77         self.user_data = None
  78         self.args = None
  79         self.matches = None
  80         self.error = None
  81         self.job = None
  82 
  83     @classmethod
  84     def from_error(cls, update, error, dispatcher):
  85         self = cls.from_update(update, dispatcher)
  86         self.error = error
  87         return self
  88 
  89     @classmethod
  90     def from_update(cls, update, dispatcher):
  91         self = cls(dispatcher)
  92         if update is not None and isinstance(update, Update):
  93             chat = update.effective_chat
  94             user = update.effective_user
  95 
  96             if chat:
  97                 self.chat_data = dispatcher.chat_data[chat.id]
  98             if user:
  99                 self.user_data = dispatcher.user_data[user.id]
  100         return self
  101 
  102     @classmethod
  103     def from_job(cls, job, dispatcher):
  104         self = cls(dispatcher)
  105         self.job = job
  106         return self
  107 
  108     def update(self, data):
  109         self.__dict__.update(data)
  110 
  111     @property
  112     def bot(self):
  113         """:class:`telegram.Bot`: The bot associated with this context."""
  114         return self._dispatcher.bot
  115 
  116     @property
  117     def job_queue(self):
  118         """
  119         :class:`telegram.ext.JobQueue`: The ``JobQueue`` used by the
  120             :class:`telegram.ext.Dispatcher` and (usually) the :class:`telegram.ext.Updater`
  121             associated with this context.
  122 
  123         """
  124         return self._dispatcher.job_queue
  125 
  126     @property
  127     def update_queue(self):
  128         """
  129         :class:`queue.Queue`: The ``Queue`` instance used by the
  130             :class:`telegram.ext.Dispatcher` and (usually) the :class:`telegram.ext.Updater`
  131             associated with this context.
  132 
  133         """
  134         return self._dispatcher.update_queue
  135 
  136     @property
  137     def match(self):
  138         """
  139         `Regex match type`: The first match from :attr:`matches`.
  140             Useful if you are only filtering using a single regex filter.
  141             Returns `None` if :attr:`matches` is empty.
  142         """
  143         try:
  144             return self.matches[0]  # pylint: disable=unsubscriptable-object
  145         except (IndexError, TypeError):
  146             return None
  147
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py
  --- a/telegram/ext/callbackcontext.py
  +++ b/telegram/ext/callbackcontext.py
  @@ -73,13 +73,31 @@
               raise ValueError('CallbackContext should not be used with a non context aware '
                                'dispatcher!')
           self._dispatcher = dispatcher
  -        self.chat_data = None
  -        self.user_data = None
  +        self._chat_data = None
  +        self._user_data = None
           self.args = None
           self.matches = None
           self.error = None
           self.job = None
   
  +    @property
  +    def chat_data(self):
  +        return self._chat_data
  +
  +    @chat_data.setter
  +    def chat_data(self, value):
  +        raise AttributeError("You can not assign a new value to chat_data, see "
  +                             "https://git.io/fjxKe")
  +
  +    @property
  +    def user_data(self):
  +        return self._user_data
  +
  +    @user_data.setter
  +    def user_data(self, value):
  +        raise AttributeError("You can not assign a new value to user_data, see "
  +                             "https://git.io/fjxKe")
  +
       @classmethod
       def from_error(cls, update, error, dispatcher):
           self = cls.from_update(update, dispatcher)
  @@ -94,9 +112,9 @@
               user = update.effective_user
   
               if chat:
  -                self.chat_data = dispatcher.chat_data[chat.id]
  +                self._chat_data = dispatcher.chat_data[chat.id]
               if user:
  -                self.user_data = dispatcher.user_data[user.id]
  +                self._user_data = dispatcher.user_data[user.id]
           return self
   
       @classmethod
  
verification_info: {"golden_diff": "diff --git a/telegram/ext/callbackcontext.py b/telegram/ext/callbackcontext.py\n--- a/telegram/ext/callbackcontext.py\n+++ b/telegram/ext/callbackcontext.py\n@@ -73,13 +73,31 @@\n             raise ValueError('CallbackContext should not be used with a non context aware '\n                              'dispatcher!')\n         self._dispatcher = dispatcher\n-        self.chat_data = None\n-        self.user_data = None\n+        self._chat_data = None\n+        self._user_data = None\n         self.args = None\n         self.matches = None\n         self.error = None\n         self.job = None\n \n+    @property\n+    def chat_data(self):\n+        return self._chat_data\n+\n+    @chat_data.setter\n+    def chat_data(self, value):\n+        raise AttributeError(\"You can not assign a new value to chat_data, see \"\n+                             \"https://git.io/fjxKe\")\n+\n+    @property\n+    def user_data(self):\n+        return self._user_data\n+\n+    @user_data.setter\n+    def user_data(self, value):\n+        raise AttributeError(\"You can not assign a new value to user_data, see \"\n+                             \"https://git.io/fjxKe\")\n+\n     @classmethod\n     def from_error(cls, update, error, dispatcher):\n         self = cls.from_update(update, dispatcher)\n@@ -94,9 +112,9 @@\n             user = update.effective_user\n \n             if chat:\n-                self.chat_data = dispatcher.chat_data[chat.id]\n+                self._chat_data = dispatcher.chat_data[chat.id]\n             if user:\n-                self.user_data = dispatcher.user_data[user.id]\n+                self._user_data = dispatcher.user_data[user.id]\n         return self\n \n     @classmethod\n", "issue": "Forbid setting user and chat data attributes\nInevitably users will attempt to do `context.user_data = {'my': 'dict'}` or `context.chat_data = whatever`. This will lead to confusing behaviour.\r\n\r\nI propose making those fields properties without a setter, which will more helpfully error. Depending on how far we want to go, we can also suggest the user to use `update(other_dict)` if they attempt to set the field.\r\n\r\nSee https://t.me/pythontelegrambotgroup/222138 onwards.\n", "before_files": [{"content": "#!/usr/bin/env python\n#\n# A library that provides a Python interface to the Telegram Bot API\n# Copyright (C) 2015-2018\n# Leandro Toledo de Souza <devs@python-telegram-bot.org>\n#\n# This program is free software: you can redistribute it and/or modify\n# it under the terms of the GNU Lesser Public License as published by\n# the Free Software Foundation, either version 3 of the License, or\n# (at your option) any later version.\n#\n# This program is distributed in the hope that it will be useful,\n# but WITHOUT ANY WARRANTY; without even the implied warranty of\n# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n# GNU Lesser Public License for more details.\n#\n# You should have received a copy of the GNU Lesser Public License\n# along with this program.  If not, see [http://www.gnu.org/licenses/].\n\"\"\"This module contains the CallbackContext class.\"\"\"\n\nfrom telegram import Update\n\n\nclass CallbackContext(object):\n    \"\"\"\n    This is a context object passed to the callback called by :class:`telegram.ext.Handler`\n    or by the :class:`telegram.ext.Dispatcher` in an error handler added by\n    :attr:`telegram.ext.Dispatcher.add_error_handler` or to the callback of a\n    :class:`telegram.ext.Job`.\n\n    Note:\n        :class:`telegram.ext.Dispatcher` will create a single context for an entire update. This\n        means that if you got 2 handlers in different groups and they both get called, they will\n        get passed the same `CallbackContext` object (of course with proper attributes like\n        `.matches` differing). This allows you to add custom attributes in a lower handler group\n        callback, and then subsequently access those attributes in a higher handler group callback.\n        Note that the attributes on `CallbackContext` might change in the future, so make sure to\n        use a fairly unique name for the attributes.\n\n    Warning:\n         Do not combine custom attributes and @run_async. Due to how @run_async works, it will\n         almost certainly execute the callbacks for an update out of order, and the attributes\n         that you think you added will not be present.\n\n    Attributes:\n        chat_data (:obj:`dict`, optional): A dict that can be used to keep any data in. For each\n            update from the same chat it will be the same ``dict``.\n        user_data (:obj:`dict`, optional): A dict that can be used to keep any data in. For each\n            update from the same user it will be the same ``dict``.\n        matches (List[:obj:`re match object`], optional): If the associated update originated from\n            a regex-supported handler or had a :class:`Filters.regex`, this will contain a list of\n            match objects for every pattern where ``re.search(pattern, string)`` returned a match.\n            Note that filters short circuit, so combined regex filters will not always\n            be evaluated.\n        args (List[:obj:`str`], optional): Arguments passed to a command if the associated update\n            is handled by :class:`telegram.ext.CommandHandler`, :class:`telegram.ext.PrefixHandler`\n            or :class:`telegram.ext.StringCommandHandler`. It contains a list of the words in the\n            text after the command, using any whitespace string as a delimiter.\n        error (:class:`telegram.TelegramError`, optional): The Telegram error that was raised.\n            Only present when passed to a error handler registered with\n            :attr:`telegram.ext.Dispatcher.add_error_handler`.\n        job (:class:`telegram.ext.Job`): The job that that originated this callback.\n            Only present when passed to the callback of :class:`telegram.ext.Job`.\n\n    \"\"\"\n\n    def __init__(self, dispatcher):\n        \"\"\"\n        Args:\n            dispatcher (:class:`telegram.ext.Dispatcher`):\n        \"\"\"\n        if not dispatcher.use_context:\n            raise ValueError('CallbackContext should not be used with a non context aware '\n                             'dispatcher!')\n        self._dispatcher = dispatcher\n        self.chat_data = None\n        self.user_data = None\n        self.args = None\n        self.matches = None\n        self.error = None\n        self.job = None\n\n    @classmethod\n    def from_error(cls, update, error, dispatcher):\n        self = cls.from_update(update, dispatcher)\n        self.error = error\n        return self\n\n    @classmethod\n    def from_update(cls, update, dispatcher):\n        self = cls(dispatcher)\n        if update is not None and isinstance(update, Update):\n            chat = update.effective_chat\n            user = update.effective_user\n\n            if chat:\n                self.chat_data = dispatcher.chat_data[chat.id]\n            if user:\n                self.user_data = dispatcher.user_data[user.id]\n        return self\n\n    @classmethod\n    def from_job(cls, job, dispatcher):\n        self = cls(dispatcher)\n        self.job = job\n        return self\n\n    def update(self, data):\n        self.__dict__.update(data)\n\n    @property\n    def bot(self):\n        \"\"\":class:`telegram.Bot`: The bot associated with this context.\"\"\"\n        return self._dispatcher.bot\n\n    @property\n    def job_queue(self):\n        \"\"\"\n        :class:`telegram.ext.JobQueue`: The ``JobQueue`` used by the\n            :class:`telegram.ext.Dispatcher` and (usually) the :class:`telegram.ext.Updater`\n            associated with this context.\n\n        \"\"\"\n        return self._dispatcher.job_queue\n\n    @property\n    def update_queue(self):\n        \"\"\"\n        :class:`queue.Queue`: The ``Queue`` instance used by the\n            :class:`telegram.ext.Dispatcher` and (usually) the :class:`telegram.ext.Updater`\n            associated with this context.\n\n        \"\"\"\n        return self._dispatcher.update_queue\n\n    @property\n    def match(self):\n        \"\"\"\n        `Regex match type`: The first match from :attr:`matches`.\n            Useful if you are only filtering using a single regex filter.\n            Returns `None` if :attr:`matches` is empty.\n        \"\"\"\n        try:\n            return self.matches[0]  # pylint: disable=unsubscriptable-object\n        except (IndexError, TypeError):\n            return None\n", "path": "telegram/ext/callbackcontext.py"}], "after_files": [{"content": "#!/usr/bin/env python\n#\n# A library that provides a Python interface to the Telegram Bot API\n# Copyright (C) 2015-2018\n# Leandro Toledo de Souza <devs@python-telegram-bot.org>\n#\n# This program is free software: you can redistribute it and/or modify\n# it under the terms of the GNU Lesser Public License as published by\n# the Free Software Foundation, either version 3 of the License, or\n# (at your option) any later version.\n#\n# This program is distributed in the hope that it will be useful,\n# but WITHOUT ANY WARRANTY; without even the implied warranty of\n# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n# GNU Lesser Public License for more details.\n#\n# You should have received a copy of the GNU Lesser Public License\n# along with this program.  If not, see [http://www.gnu.org/licenses/].\n\"\"\"This module contains the CallbackContext class.\"\"\"\n\nfrom telegram import Update\n\n\nclass CallbackContext(object):\n    \"\"\"\n    This is a context object passed to the callback called by :class:`telegram.ext.Handler`\n    or by the :class:`telegram.ext.Dispatcher` in an error handler added by\n    :attr:`telegram.ext.Dispatcher.add_error_handler` or to the callback of a\n    :class:`telegram.ext.Job`.\n\n    Note:\n        :class:`telegram.ext.Dispatcher` will create a single context for an entire update. This\n        means that if you got 2 handlers in different groups and they both get called, they will\n        get passed the same `CallbackContext` object (of course with proper attributes like\n        `.matches` differing). This allows you to add custom attributes in a lower handler group\n        callback, and then subsequently access those attributes in a higher handler group callback.\n        Note that the attributes on `CallbackContext` might change in the future, so make sure to\n        use a fairly unique name for the attributes.\n\n    Warning:\n         Do not combine custom attributes and @run_async. Due to how @run_async works, it will\n         almost certainly execute the callbacks for an update out of order, and the attributes\n         that you think you added will not be present.\n\n    Attributes:\n        chat_data (:obj:`dict`, optional): A dict that can be used to keep any data in. For each\n            update from the same chat it will be the same ``dict``.\n        user_data (:obj:`dict`, optional): A dict that can be used to keep any data in. For each\n            update from the same user it will be the same ``dict``.\n        matches (List[:obj:`re match object`], optional): If the associated update originated from\n            a regex-supported handler or had a :class:`Filters.regex`, this will contain a list of\n            match objects for every pattern where ``re.search(pattern, string)`` returned a match.\n            Note that filters short circuit, so combined regex filters will not always\n            be evaluated.\n        args (List[:obj:`str`], optional): Arguments passed to a command if the associated update\n            is handled by :class:`telegram.ext.CommandHandler`, :class:`telegram.ext.PrefixHandler`\n            or :class:`telegram.ext.StringCommandHandler`. It contains a list of the words in the\n            text after the command, using any whitespace string as a delimiter.\n        error (:class:`telegram.TelegramError`, optional): The Telegram error that was raised.\n            Only present when passed to a error handler registered with\n            :attr:`telegram.ext.Dispatcher.add_error_handler`.\n        job (:class:`telegram.ext.Job`): The job that that originated this callback.\n            Only present when passed to the callback of :class:`telegram.ext.Job`.\n\n    \"\"\"\n\n    def __init__(self, dispatcher):\n        \"\"\"\n        Args:\n            dispatcher (:class:`telegram.ext.Dispatcher`):\n        \"\"\"\n        if not dispatcher.use_context:\n            raise ValueError('CallbackContext should not be used with a non context aware '\n                             'dispatcher!')\n        self._dispatcher = dispatcher\n        self._chat_data = None\n        self._user_data = None\n        self.args = None\n        self.matches = None\n        self.error = None\n        self.job = None\n\n    @property\n    def chat_data(self):\n        return self._chat_data\n\n    @chat_data.setter\n    def chat_data(self, value):\n        raise AttributeError(\"You can not assign a new value to chat_data, see \"\n                             \"https://git.io/fjxKe\")\n\n    @property\n    def user_data(self):\n        return self._user_data\n\n    @user_data.setter\n    def user_data(self, value):\n        raise AttributeError(\"You can not assign a new value to user_data, see \"\n                             \"https://git.io/fjxKe\")\n\n    @classmethod\n    def from_error(cls, update, error, dispatcher):\n        self = cls.from_update(update, dispatcher)\n        self.error = error\n        return self\n\n    @classmethod\n    def from_update(cls, update, dispatcher):\n        self = cls(dispatcher)\n        if update is not None and isinstance(update, Update):\n            chat = update.effective_chat\n            user = update.effective_user\n\n            if chat:\n                self._chat_data = dispatcher.chat_data[chat.id]\n            if user:\n                self._user_data = dispatcher.user_data[user.id]\n        return self\n\n    @classmethod\n    def from_job(cls, job, dispatcher):\n        self = cls(dispatcher)\n        self.job = job\n        return self\n\n    def update(self, data):\n        self.__dict__.update(data)\n\n    @property\n    def bot(self):\n        \"\"\":class:`telegram.Bot`: The bot associated with this context.\"\"\"\n        return self._dispatcher.bot\n\n    @property\n    def job_queue(self):\n        \"\"\"\n        :class:`telegram.ext.JobQueue`: The ``JobQueue`` used by the\n            :class:`telegram.ext.Dispatcher` and (usually) the :class:`telegram.ext.Updater`\n            associated with this context.\n\n        \"\"\"\n        return self._dispatcher.job_queue\n\n    @property\n    def update_queue(self):\n        \"\"\"\n        :class:`queue.Queue`: The ``Queue`` instance used by the\n            :class:`telegram.ext.Dispatcher` and (usually) the :class:`telegram.ext.Updater`\n            associated with this context.\n\n        \"\"\"\n        return self._dispatcher.update_queue\n\n    @property\n    def match(self):\n        \"\"\"\n        `Regex match type`: The first match from :attr:`matches`.\n            Useful if you are only filtering using a single regex filter.\n            Returns `None` if :attr:`matches` is empty.\n        \"\"\"\n        try:\n            return self.matches[0]  # pylint: disable=unsubscriptable-object\n        except (IndexError, TypeError):\n            return None\n", "path": "telegram/ext/callbackcontext.py"}]}