bpo-38605: Revert making 'from __future__ import annotations' the default by pablogsal · Pull Request #25490 · python/cpython

Could you give a little bit context to explain the revert? I guess that it's related to the many threads on python-dev about it?

Is explained in the NEWs entry. I plan to explain it also on the final commit :)

@pablogsal also please bump the magic number (cached pycs might cause some issues) (it wasn't done in the initial PR, but rather get picked up on #22630)

@pablogsal also please bump the magic number (cached pycs might cause some issues) (it wasn't done in the initial PR, but rather get picked up on #22630)

We should be able to go back a version, I think. Cached pycs for alpha versions should not take lots of consideration

We should be able to go back a version, I think. Cached pycs for alpha versions should not take lots of consideration

Crap, there has been quite a lot of changes since then. Ok, bumping it is!

@pablogsal also please bump the magic number (cached pycs might cause some issues) (it wasn't done in the initial PR, but rather get picked up on #22630)

Done in ef38777a1f

Oops sorry, I wanted to remove my comment rather posting it, but I closed the PR instead... I reopened the PR.

We can also update the doc of __future__ module and Lib/__future__.py to mention that annotations feature is postponed to be "mandatory in 3.11".

	if (oparg & 0x04) {
	assert(PyTuple_CheckExact(TOP()));
	func->func_annotations = POP();
	}

This line should be changed to assert(PyTuple_CheckExact(TOP()) || PyDict_CheckExact(TOP()));.
I don't know why this pull request passes the test...

Are you taking #23316 into consideration?

Are you taking #23316 into consideration?

Yes. And I know understand why this assrtion passes.

def add(a: int, b: int) -> int:
    return a + b

  3           0 LOAD_CONST               0 ('a')
              2 LOAD_NAME                0 (int)
              4 LOAD_CONST               1 ('b')
              6 LOAD_NAME                0 (int)
              8 LOAD_CONST               2 ('return')
             10 LOAD_NAME                0 (int)
             12 BUILD_TUPLE              6
             14 LOAD_CONST               3 (<code object add at 0x7f30fc37b050, file "a.py", line 3>)
             16 LOAD_CONST               4 ('add')
             18 MAKE_FUNCTION            4 (annotations)
             20 STORE_NAME               1 (add)

Annotation is tuple even when PEP 563 is disabled. That's nice.

🤖 New build scheduled with the buildbot fleet by @pablogsal for commit 51a6f52234cf416f33a8f8ce625502dedd2bf0fd 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

I still would like if someone can formally approve the PR :)

LGTM but please address first the comment in Lib/test/test_dataclasses.py (I concur that it looks a revert of a bugfix, so it reintroduces a typo).

I suggest to first revert the change, and then write a second PR to announce that annotations are going to change again (in Python 3.11 or later).

I suggest to first revert the change, and then write a second PR to announce that annotations are going to change again (in Python 3.11 or later).

@vstinner What do you mean when you say "announce"? Announce where? In the What's new? A news entry? python-dev?

I suggest to first revert the change

Notice that this was certainly not a clean revert

@vstinner What do you mean when you say "announce"? Announce where? In the What's new? A news entry? python-dev?

Add a What's New in Python 3.10 entry to explain that the behavior changed but was then revert, and that it will change again in a future Python version.

Something like this announcement of future collections incompatible changes (collections.Mapping alias):
https://docs.python.org/dev/whatsnew/3.9.html#you-should-check-for-deprecationwarning-in-your-code

This announce was correct: the aliases were removed again in Python 3.10.

python-dev?

Any additional communication would be good, but the minimum would be a note in the What's New in Python 3.10.