Re: [Python-Dev] Fwd: str(IntEnum)

On Fri, Feb 20, 2015 at 12:36 PM, Florian Bruhin wrote:

* Demian Brecht [2015-02-20 10:24:53 -0800]:

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These and other implementations return a string representation of the instance’s value, not a string representation of the object itself. Whereas elsewhere in the standard library:

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str(ProtocolError('url', 42, 'msg', '')) '’ str(URLError('reason')) '<urlopen error reason>’ str(Cookie(0, '', '', '4', '', '', '', '', '', '', '', 0, '', '', '', '')) ''

The specific problem that I encountered was when swapping an IntEnum implementation for ints in http.client, which caused a change in logging output (from int.__str__ to Enum.__str__) , which was a bit of a surprise, especially given the value is a builtin type.

I think that a decent rule around the usage of __str__ is that it should be a string representation of the value, not of the object. Failing the ability to logically coerce the value to a string, it should simply fall back to repr(obj).

Of course, I realize that the chances of this change being made to such a fundamental (and largely inconsequential) feature are likely nil, but I thought I’d share my thoughts anyways.

>>> foo = object() >>> str(foo) '