[Python-Dev] PEP 509: Add a private version to dict

[Yury Selivanov]

On 2016-01-20 5:01 PM, Greg Ewing wrote:
> Yury Selivanov wrote:
>> What I propose is to add a pointer "ma_extra" (same 64bits),
>> which will be set to NULL for most dict instances (instead of
>> ma_version).  "ma_extra" can then point to a struct that has a
>> globally unique dict ID (uint64), and a version tag (unit64).
>
> Why not just use a single global counter for allocating
> dict version tags, instead of one per dict?
>


Yeah, I think that's what we agreed on: 
https://mail.python.org/pipermail/python-dev/2016-January/142837.html

The only advantage of ma_extra pointer is that it allows to add more 
stuff to dicts in the future.

Yury