[Python-Dev] Can Python guarantee the order of keyword-only parameters? (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Tue Nov 28 23:55:37 EST 2017

On 29 November 2017 at 03:13, Brett Cannon <brett at python.org> wrote:

On Tue, 28 Nov 2017 at 03:33 Nick Coghlan <ncoghlan at gmail.com> wrote:

P.S. Note that inspect.getfullargspec() was actually undeprecated a while back - enough folks that didn't need access to the function annotations were reimplementing it for themselves "because the standard library API is deprecated" that the most logical course of action was to just declare it as being supported again. I don't think that changes the argument here though - it just means guaranteed order preservation in that API will only happen if we declare dicts to be insertion ordered in general. OT for this thread, but is there an issue number tracking the un-deprecating? Basically I want to make sure there is an issue tracking deprecating it again when we stop worrying about any Python 2/3 support.

The issue is https://bugs.python.org/issue27172, but the undeprecation isn't a Python 2/3 issue, it's a "tuples, lists and dicts are really handy representations of things, and Python developers often prefer them to more structured objects" issue.

The modern inspect.getfullargspec implementation is a relatively thin wrapper around inspect.signature, and the only lossy part of the output transformation is that you can't tell the difference between positional-only and positional-or-keyword parameters.

Cheers, Nick.

-- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia

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