More of a meta-point, and a reminder: A PEP that has been accepted should not be changed. We used to allow this in some cases, but unless it's merely to clarify wording, PEPs are change specifications, and if you want to change anything you have to either do it as a new PEP or treat it as a minor new feature in the next Python release. Not every new feature requires a PEP. But PEPs are not documentation, and if the behavior changes, the PEP has to stay behind.

On Wed, Apr 6, 2022 at 4:48 PM S Pradeep Kumar <gohanpra@gmail.com> wrote:
Thanks to everyone who attended today's meetup. We had a pretty heated debate towards the end, so if you missed part of it, you can check out the recording, chat, and slides in the running Google Doc [1].

1. Inference carve-outs: Shannon Zhu and Eric Traut [2]. Type checkers differ in their behavior for many cases of unannotated variables, function parameters, or attributes. Shannon and Eric pointed out some of these cases and argued that we should standardize on the behavior for some, if not all, of them. I polled the participants and found 16 in favor of standardization, none against, and 2 saying “I don’t know”. Follow-up: We probably need to find a good way to standardize this.

2. TypedDicts and Extra Fields: Jonathan Scholbach and Steven Troxler [3]. 

Jonathan and Steven pointed out that, if we have a `BaseTypedDict` and a subtype `ChildTypedDict`, it is legal to assign a dictionary literal containing child-specific keys to a variable of type `ChildTypedDict` and then assign it to a TypedDict `BaseTypedDict`. But it is illegal to assign the dictionary literal directly to `BaseTypedDict`. They argued that this can be confusing for some users. Others argued that this feature prevented users from having a typo in a non-required field, which would not be caught by the type checker otherwise. We were discussing whether or not this warranted a change in the PEP and seemed to agree that we could get away with a clearer error message. We didn't actually get around to discussing whether to add a new `extra=True` flag to allow reading and writing arbitrary extra fields, as in TypeScript or Hack, and what the semantics would be (especially with subtyping).

Note: I'm sure people still have some points they want to make! Please continue the discussion in the OTHER, dedicated typing-sig thread [4], so that this thread is purely about Typing Meetup logistics.

3. PyCon Typing Summit: We'll be having a Typing Summit at PyCon on Thursday, April 28th from 1-5 pm: https://us.pycon.org/2022/events/typing-summit/. So, we'll have the next monthly Typing Meetup in late May.


On Wed, Apr 6, 2022 at 6:00 AM S Pradeep Kumar <gohanpra@gmail.com> wrote:
Reminder that the Typing Meetup is today at 10:00 am San Francisco time (UTC-7) / 6:00 pm London time (UTC+1).

--
S Pradeep Kumar


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S Pradeep Kumar
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