pytest >= 5.4.0 raises INTERNALERROR AttributeError with pytest-sugar installed #6951
Description
With both 5.4.0 and 5.4.1, running pytest in the following environment:
```
$ pip list
Package Version
------------------ -------
apipkg 1.5
attrs 19.3.0
coverage 5.0.4
execnet 1.7.1
importlib-metadata 1.5.0
more-itertools 8.2.0
packaging 20.3
pip 20.0.2
pluggy 0.13.1
py 1.8.1
pyparsing 2.4.6
pytest 5.4.1
pytest-cov 2.8.1
pytest-forked 1.1.3
pytest-html 2.1.1
pytest-metadata 1.8.0
pytest-sugar 0.9.2
pytest-xdist 1.31.0
setuptools 46.0.0
six 1.14.0
termcolor 1.1.0
wcwidth 0.1.8
wheel 0.34.2
zipp 3.1.0
```
Raises the following error:
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/_pytest/main.py", line 187, in wrap_session
INTERNALERROR> config._do_configure()
:INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/_pytest/config/__init__.py", line 820, in _do_configure
INTERNALERROR> self.hook.pytest_configure.call_historic(kwargs=dict(config=self))
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pluggy/hooks.py", line 308, in call_historic
INTERNALERROR> res = self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pluggy/manager.py", line 93, in _hookexec
INTERNALERROR> return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pluggy/manager.py", line 87, in <lambda>
INTERNALERROR> firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR> File "/~foo/.venv/lib/python3.6/site-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR> return outcome.get_result()
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pluggy/callers.py", line 80, in get_result
INTERNALERROR> raise ex[1].with_traceback(ex[2])
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR> res = hook_impl.function(*args)
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pytest_sugar.py", line 171, in pytest_configure
INTERNALERROR> sugar_reporter = SugarTerminalReporter(standard_reporter)
INTERNALERROR> File "~/foo/.venv/lib/python3.6/site-packages/pytest_sugar.py", line 209, in __init__
INTERNALERROR> self.writer = self._tw
INTERNALERROR> AttributeError: can't set attribute
Note that the above environment is the result of installing the following requirements into a clean virtualenv:
pytest
pytest-cov
pytest-forked
pytest-html
pytest-metadata
pytest-sugar
pytest-xdist
Uninstalling pytest-sugar fixes the issue, as does downgrading pytest to 5.3.5.
I've experienced this error with python 3.6.8 on Ubuntu 18.04, and python 3.7.3 on macOS Catalina.