[Python-ideas] RFC: PEP: Add dict.__version__

[Serhiy Storchaka]

On 08.01.16 23:27, Victor Stinner wrote:
> Add a new read-only ``__version__`` property to ``dict`` and
> ``collections.UserDict`` types, incremented at each change.

This may be not the best name for a property. Many modules already have 
the __version__ attribute, this may make a confusion.

> The C code uses ``version++``. The behaviour on integer overflow of the
> version is undefined. The minimum guarantee is that the version always
> changes when the dictionary is modified.

For clarification, this code has defined behavior in C (we should avoid 
introducing new undefined behaviors). May be you mean that the bahavior 
is not specified from Python side (since it is platform and 
implementation defined).

> Usage of dict.__version__
> =========================

This also can be used for better detecting dict mutating during 
iterating: https://bugs.python.org/issue19332.