[New-bugs-announce] [issue42848] asyncio produces an unexpected traceback with recursive __getattribute__

[asleep-cult]

New submission from asleep-cult <asleep.cult at gmail.com>:

The code below produces an unexpected traceback format that makes the source of an error very hard to find, this more than likely happens in less specific situations but this is how I came across it. I'm also not sure if this is an issue with asyncio, logging or the traceback module.


import asyncio

class Bar:
    def __init__(self):
        self.y = None

class Foo:
    def __init__(self):
        self._bar = Bar()
        self.y

    def __getattribute__(self, name):
        try:
            attr = super().__getattribute__(name)
        except AttributeError as e:
            try:
                attr = self.ooops_spelled_bar_wrong.__getattribute__(name)
            except AttributeError:
                raise e
        return attr

async def foo():
    Foo()

loop = asyncio.get_event_loop()
loop.create_task(foo())
loop.run_forever()


Traceback:


Exception in default exception handler
Traceback (most recent call last):
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 1733, in call_exception_handler    self.default_exception_handler(context)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 1707, in default_exception_handler
    logger.error('\n'.join(log_lines), exc_info=exc_info)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 1471, in error
    self._log(ERROR, msg, args, **kwargs)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 1585, in _log
    self.handle(record)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 1595, in handle
    self.callHandlers(record)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 1665, in callHandlers
    lastResort.handle(record)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 950, in handle
    self.emit(record)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 1081, in emit
    msg = self.format(record)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 925, in format
    return fmt.format(record)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 672, in format
    record.exc_text = self.formatException(record.exc_info)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\logging\__init__.py", line 622, in formatException
    traceback.print_exception(ei[0], ei[1], tb, None, sio)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 103, in print_exception
    for line in TracebackException(
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 493, in __init__
    context = TracebackException(
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 493, in __init__
    context = TracebackException(
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 493, in __init__
    context = TracebackException(
  [Previous line repeated 488 more times]
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 476, in __init__
    _seen.add(id(exc_value))
RecursionError: maximum recursion depth exceeded while calling a Python object
``` 

The code below procures the expected traceback

 
import traceback

class Bar:
    def __init__(self):
        self.y = None

class Foo:
    def __init__(self):
        self._bar = Bar()
        self.y

    def __getattribute__(self, name):
        try:
            attr = super().__getattribute__(name)
        except AttributeError as e:
            try:
                attr = self.ooops_spelled_bar_wrong.__getattribute__(name)
            except AttributeError:
                raise e
        return attr

try:
    Foo()
except:
    traceback.print_exc()


Traceback:


During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:/Development/test/test.py", line 15, in __getattribute__
    attr = super().__getattribute__(name)
AttributeError: 'Foo' object has no attribute 'ooops_spelled_bar_wrong'

# The part above is repeated hundreds of times

Traceback (most recent call last):
  File "c:/Development/test/test.py", line 24, in <module>
    Foo()
  File "c:/Development/test/test.py", line 11, in __init__
    self.y
  File "c:/Development/test/test.py", line 18, in __getattribute__
    attr = self.ooops_spelled_bar_wrong.__getattribute__(name)
  File "c:/Development/test/test.py", line 18, in __getattribute__
    attr = self.ooops_spelled_bar_wrong.__getattribute__(name)
  File "c:/Development/test/test.py", line 18, in __getattribute__
    attr = self.ooops_spelled_bar_wrong.__getattribute__(name)
  [Previous line repeated 992 more times]
  File "c:/Development/test/test.py", line 15, in __getattribute__
    attr = super().__getattribute__(name)
RecursionError: maximum recursion depth exceeded while calling a Python object

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:/Development/test/test.py", line 26, in <module>
    traceback.print_exc()
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 163, in print_exc
    print_exception(*sys.exc_info(), limit=limit, file=file, chain=chain)
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 103, in print_exception
    for line in TracebackException(
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 493, in __init__
    context = TracebackException(
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 493, in __init__
    context = TracebackException(
  File "C:\Users\User\AppData\Local\Programs\Python\Python38\lib\traceback.py", line 493, in __init__
    context = TracebackException(
  [Previous line repeated 495 more times]
RecursionError: maximum recursion depth exceeded

----------
components: Library (Lib)
messages: 384551
nosy: asleep-cult
priority: normal
severity: normal
status: open
title: asyncio produces an unexpected traceback with recursive __getattribute__
type: behavior
versions: Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue42848>
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