This is happening, right? Adding a default `__annotations = {}` to modules and classes. (Though seems temporarily stuck.)

On Mon, Apr 19, 2021 at 10:10 PM Larry Hastings <> wrote:

As long as I'm gravedigging old conversations...!  Remember this one, also from January of this year?  Here's a link to the thread in the c.l.p-d Mailman archive.  The first message in the thread is a good overview of the problem:

Here's kind of where we left it:

On 1/12/21 7:48 PM, Guido van Rossum wrote:
On Tue, Jan 12, 2021 at 6:35 PM Larry Hastings <> wrote:
On 1/12/21 5:28 PM, Brett Cannon wrote:
The other thing to keep in mind is we are talking about every module, class, and function getting 64 bytes ... which I bet isn't that much.

Actually it's only every module and class.  Functions don't have this problem because they've always stored __annotations__ internally--meaning, peeking in their __dict__ doesn't work, and they don't support inheritance anyway.  So the number is even smaller than that.

If we can just make __annotations__ default to an empty dict on classes and modules, and not worry about the memory consumption, that goes a long way to cleaning up the semantics.

I would like that very much. And the exception for functions is especially helpful.

First of all, I've proposed a function that should also help a lot:

The function will be called inspect.get_annotations(o).  It's like typing.get_type_hints(o) except less opinionated.  This function would become the best practice for everybody who wants annotations**, like so:

import inspect
if hasattr(inspect, "get_annotations"):
    how_i_get_annotations = inspect.get_annotations
    # do whatever it was I did in Python 3.9 and before...

** Everybody who specifically wants type hints should instead call typing.get_type_hints(), and good news!, that function has existed for several versions now.  So they probably already do call it.

I'd still like to add a default empty __annotations__ dict to all classes and modules for Python 3.10, for everybody who doesn't switch to using this as-yet-unwritten inspect.get_annotations() function.  The other changes I propose in that thread (e.g. deleting __annotations__ always throws TypeError) would be nice, but honestly they aren't high priority.  They can wait until after Python 3.10.  Just these these two things (inspect.get_annotations() and always populating __annotations__ for classes and modules) would go a long way to cleaning up how people examine annotations.

Long-term, hopefully we can fold the desirable behaviors of inspect.get_annotations() into the language itself, at which point we could probably deprecate the function.  That wouldn't be until a long time from now of course.

Does this need a lot of discussion, or can I just go ahead with the bpo and PR and such?  I mean, I'd JFDI, as Barry always encourages, but given how much debate we've had over annotations in the last two weeks, I figured I should first bring it up here.

Happy two-weeks'-notice,


p.s. I completely forgot about this until just now--sorry.  At least I remembered before Python 3.10b1!

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