[breischl]

I read the article as saying it ignores all upper-bounds, and 4.0 is just an example. I could be wrong though - it seems ambiguous to me.

But if we accept that it currently ignores any upper-bounds checks greater than v3, that's interesting. Does that imply that once Python 4 is available, uv will slow down due to needing to actually run those checks?

[VorpalWay]

Are there any plans to actually make a 4.0 ever? I remember hearing a few years ago that after the transition to 3.0, the core devs kind of didn't want to repeat that mess ever again.

That said, even if it does happen, I highly doubt that is the main part of the speed up compared to pip.

[bastawhiz]

I think there's a future where we get a 4.0, but it's not any time soon. I think they'd want an incredibly compelling backwards-incompatible feature before ripping that band-aid off. It would be setting up for a decade of transition, which shouldn't be taken lightly.

[zahlman]

There are indeed not any such plans.

[cmrx64]

That would deliver a blow to the integrity of the rest of that section because those sorts of upper bound constraints immediately reducible to “true” cannot cause backtracking of any kind.