On Tue, Jul 10, 2018 at 2:30 AM Paul Moore email@example.com wrote:
On 9 July 2018 at 20:27, Pradyun Gedam firstname.lastname@example.org wrote:
On Sun, Jul 8, 2018 at 9:14 AM Nathaniel Smith email@example.com wrote:
This suggests that our decision should be based on: if we want to be relatively more aggressive about rolling out build isolation, then we should key on the existence of pyproject.toml. If we want to be relatively more conservative, then we should key on the existence of build-system.requires.
Indeed. I too feel that's what this comes down to. I had a wordier way to come to this conclusion which I've removed from this mail now. :)
An important thing here is that being aggressive here let's us piggy-back on the adoption of tools that use pyproject.toml and I'd say it's a good thing to have more people using the standard explicitly.
OK. That's basically pip's current behaviour.
This discussion is getting fragmented, unfortunately. I've just commented on the pip issue at https://github.com/pypa/pip/issues/5416#issuecomment-403616780 as I'm still trying to find the motivating issues behind this discussion.
For now I'll point out that PEP 518 doesn't say *anything* about how tools use the information in `pyproject.toml` - there's no mention of build isolation. Unless I missed something - please point it out if I did, The only thing I can find is in PEP 517. So discussions of pip's isolation behaviour are mostly pip-specific implementation details at the moment, and not really relevant to this thread.
Ah, okay. So, isolation is purely an implementation issue, so it doesn't need to come around in this discussion which is about how we should change the PEP. I guess I'm still figuring out where to draw the line between implementation details and the PEP details here since they should/would influence each other both ways. I'll try to be more careful about stuff like this in the future. :)
Once I've collected a bit more information, I'll summarise here. But I think there's only minor changes to PEP 518 needed, and nothing for pip.