Comment by leni536

The section about the "perfect ABI stability" is rather naive. If you have a 3rd party library that exposes a class like this in a header:

  class SomePublicClass {
    pystd::HashMap<pystd::U8String, size_t> member;
    /*...*/
  };

and distribute that 3rd party library as compiled against a particular pystd version and the headers, then that build is tied to one particular "epoch" or version of pystd, you can't safely link that library against a program that uses a different "epoch" of pystd.

It's also not a new idea either. libc++ puts everything inside an inline namespace `std::__1`. There is a reason that they never bumped that.