Improve sqlite3 types

[JelleZijlstra]

No description provided.

[JelleZijlstra]

The new errors are correct but possibly too pedantic. I made fetchone() return Any | None, because it can in fact return None: https://github.com/python/cpython/blob/055760ed9e745a3104acbfa8a3b76eb26a72590d/Modules/_sqlite/cursor.c#L829. But often you know that there's at least one row (e.g., because you ran a COUNT query), so I'd be open to changing it back to Any. This is similar to the issues we've had with re.match possibly returning None.

[AlexWaygood]

The new errors are correct but possibly too pedantic. I made fetchone() return Any | None, because it can in fact return None: https://github.com/python/cpython/blob/055760ed9e745a3104acbfa8a3b76eb26a72590d/Modules/_sqlite/cursor.c#L829. But often you know that there's at least one row (e.g., because you ran a COUNT query), so I'd be open to changing it back to Any. This is similar to the issues we've had with re.match possibly returning None.

If the aim is to get these new stubs in before the next mypy release, maybe it'd be best to change it back to Any for now, and we can revisit it later?

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

rclip (https://github.com/yurijmikhalevich/rclip)
+ rclip/db.py:70: error: Argument 1 to "update" of "MutableMapping" has incompatible type "NewImage"; expected "SupportsKeysAndGetItem[str, None]"
+ rclip/db.py:70: note:         def __getitem__(self, str) -> None
- rclip/db.py:70: error: Argument 1 to "update" of "MutableMapping" has incompatible type "NewImage"; expected "SupportsKeysAndGetItem[Any, None]"
- rclip/db.py:70: note:         def __getitem__(self, Any) -> None