If you write "from typing import *" you get "re" and "io" for free, which is surprising if this import occurs after an actual "import re" or "import io".

The solution is not to include those two in __all__. You can still use them -- use "from typing import re" explicitly or reference them as "typing.re".

Because typing is provisional I'll fix this in 3.5.2 as well.

Cross-reference: https://github.com/python/typing/issues/178

I would argue against changing this. They seem to be documented classes, so I guess this would break pydoc. It is a similar situation to os.open(), threading.enumerate(), etc. But I don’t have a strong opinion, and accept other people like keeping __all__ a minimal set of names and not reflecting the full API.

Well, PEP 484 and typing.py are provisional. So small changes, even to documented behavior, are fine.  (I'm also changing @overload, per the change in PEP 484 that was discussed recently.)

Can you suggest a doc change?

My concern with pydoc is that currently when you do “python -m pydoc typing” you get stuff like

CLASSES
    builtins.object
        typing.io
        typing.re
        [. . .]
    
    io = class typing.io(builtins.object)
     |  Wrapper namespace for IO generic classes.
     |  [. . .]
    
    re = class typing.re(builtins.object)
     |  Wrapper namespace for re type aliases.
     |  [. . .]

If I comment out these two entries from typing.__all__, there is no longer any mention of “re” or “io” in the pydoc output.

I'm no expert on pydoc, but I don't think it should be a reason to
keep these two names in __all__; __all__ is there primarily to guide
"import *" and it's clear that "from typing import *" overwriting a
previously-imported re or io module is a bad idea.

But maybe pydoc just needs to learn to look for another variable in
addition to __all__? Maybe __alldoc__?

The __alldoc__ is an interesting idea to think about. Anyway, I haven’t actually tried the typing module yet, so I will let you decide the best way forward.

New changeset be3c4151d9bf by Guido van Rossum in branch '3.5':
Many changes from the upstream repo (https://github.com/python/typing).
https://hg.python.org/cpython/rev/be3c4151d9bf