Alex Waygood

> Hmm interesting. It seems that just including vendored file system causes a 60% perf regression because dropping it (the Zip has a ton of metadata) is so expensive. I...

> Hmm yeah, but we would also need to make it lazy in `Program` I don't think `Program` would need to own a reference to it if it was just...

Why does each test need to have its own `VendoredFileSystem` instance? I thought we agreed that using `--custom-typeshed-dir` and the `MemoryFileSystem` was sufficient for mocking out typeshed in tests. I...

> Either way. I prefer not to solve this as part of this PR. Sure — the reason for my questions was I was trying to understand the motivation for...

> Using the `with` introduced variable after the `with` block is more common and often acceptable. @AlexWaygood would you mind sharing an example? A commit merged to the CPython repo...

> The function should actually go to `typing` instead of `functools` as so it can be backported to older versions of python. We occasionally backport typing-adjacent things from other modules...

Your suggested guidelines LGTM overall. I have a couple of wording nitpicks, but probably better left as PR comments; I don't object to any of the overall substance!

I think @carljm is almost certainly our best django expert on the team 😄 Whereas I have never used django, Carl was both a member of the django core team...

Yeah, would definitely encourage y'all to do detailed perf testing before making any decisions. We made a ton of optimisations to `isinstance()` checks against `typing.Protocol` in 3.12 and they're _way_...

I wondered whether these docs would be better placed somewhere like https://typing.readthedocs.io/en/latest/. But I'm not sure it would be a great fit for that site, because: - Some of the...