[issue28385] Non-informative exception while formatting strings.

[Марк Коренберг]

New submission from Марк Коренберг:

$ python3 -c "'{0:s}'.format(b'qwe')"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: non-empty format string passed to object.__format__

Spent many hours to detect bug in my code.

----------
components: Library (Lib)
messages: 278244
nosy: mmarkk
priority: normal
severity: normal
status: open
title: Non-informative exception while formatting strings.
versions: Python 3.5, Python 3.6, Python 3.7

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue28385>
_______________________________________