Hm, I guess this should just be a property that returns whatever sys.stdout.encoding is, since that's how strings are actually being decoded. What are you using this for? (asking to try to understand if this is the right solution)

I guess this should just be a property that returns whatever sys.stdout.encoding is

This is a much better solution!

What are you using this for?

I don't remember that :D

I found another AttributeError for 'FakeOutput', this time for 'fileno'. I was using PyQtGraph. Issue #628.

Proposed solution in #629

I ran into the problem in bpython import as well.
I would look at what idle does in its code base:
see cpython run.py PseudoFile class for example. if FakeOutput only encodes 'utf-8' then just return that.

Here's my +1:

$ python3
Python 3.7.2 (default, Feb 12 2019, 08:16:38) 
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pipenv
>>> 
$ bpython
bpython version 0.17.1 on top of Python 3.7.2 /usr/local/opt/python/bin/python3.7
>>> import pipenv
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    import pipenv
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/__init__.py", line 47, in <module>
    from .cli import cli
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/cli/__init__.py", line 3, in <module>
    from .command import cli
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/cli/command.py", line 19, in <module>
    from .options import (
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/cli/options.py", line 11, in <module>
    from .. import environments
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/environments.py", line 7, in <module>
    from ._compat import fix_utf8
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/_compat.py", line 96, in <module>
    OUT_ENCODING, ERR_ENCODING = force_encoding()
  File "/Users/ryan.delaney/Library/Python/3.7/lib/python/site-packages/pipenv/_compat.py", line 60, in force_encoding
    stdout_encoding = sys.stdout.encoding
AttributeError: 'FakeOutput' object has no attribute 'encoding'
>>> 

The encoding issue exists in bpython 0.19 and Python 3.8.0

$ bpython
bpython version 0.19 on top of Python 3.8.0
>>> import sys
>>> sys.stdout.encoding
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    sys.stdout.encoding
AttributeError: 'FakeOutput' object has no attribute 'encoding'
`

The encoding issue still exists in bpython 0.19 and Python 3.8.2, my use case is Z3 solver:

>>> from z3 import *
>>> Tie, Shirt = Bools('Tie Shirt')
>>> s = Solver()
>>> s.add(Or(Tie, Shirt), Or(Not(Tie), Shirt), Or(Not(Shirt), Not(Tie)))
>>> s.check()
sat
>>> s.model()
Traceback (most recent call last):

The Z3 example comes from here: https://theory.stanford.edu/~nikolaj/programmingz3.html#sec-logical-interface