Stub versioning

[JukkaL]

Several people have expressed interest in versioning stub files.

Here are some reasons:

• A library maintainer is worried that stubs maintained by 3rd parties for his or her library will get out of date, and people will complain to the library maintainer instead of the one who maintains the stubs.
• A new version of a library breaks compatibility with earlier versions and it's no longer possible to use the same stub with all version of the library in any meaningful way.

[vlasovskikh]

TypeScript guys have created a set of tools for managing their stubs:

• https://github.com/DefinitelyTyped/tsd

This is their contribution guide.

[matthiaskramm]

I like the TypeScript approach of putting the version into the file name. If we do the same thing, we might have something like
typeshed/python3/dist-packages/numpy-1.8.2.pyi

[gvanrossum]

Closing. We now have a policy for this.