[Python-Dev] Guarantee ordered dict literals in v3.7?

[Eric Fahlgren]

On Thu, Dec 21, 2017 at 7:51 PM, Stephen J. Turnbull <
turnbull.stephen.fw at u.tsukuba.ac.jp> wrote:

> I understand the motivation to guarantee order, but it's a programmer
> convenience that has nothing to do with the idea of mapping, and the
> particular (insertion) order is very special and usually neither
> relevant nor reproducible.  I have no problem whatsoever with just
> documenting any failure to preserve order while reproducing dicts,
> *except* that a process that inserts keys in the same order had better
> result in the same insertion order.
>

​json, pickle == png, i.e., guaranteed lossless.
repr, pprint == jpg, lossy for very specific motivating reasons.​

In particular, I use pprint output in regression baselines, and if the long
documented sort-by-key behavior changed, I would not be happy.
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