[New-bugs-announce] [issue36787] Python3 regresison: String formatting of None object

[Gawain Bolton]

New submission from Gawain Bolton <gawain.bolton at gmail.com>:

Python 2.7.16 (default, Apr  6 2019, 01:42:57)
[GCC 8.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.                                                                
>>> print('{:^10}'.format(None))
   None

However this does not work with Python3:
Python 3.7.3 (default, Apr  3 2019, 05:39:12)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.                                                                
>>> print('{:^10}'.format(None))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported format string passed to NoneType.__format__

Given that the None type is output as a string, it makes sense for                                                           string formatting options to be usable with it.  It also makes code                                                              less fragile and avoids having to write special cases for when values                                                             
could be None.

----------
components: Library (Lib)
messages: 341355
nosy: Gawain Bolton
priority: normal
severity: normal
status: open
title: Python3 regresison: String formatting of None object
type: behavior

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue36787>
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