On Mon, 28 Jan 2019 at 2:35 AM, Thomas Kluyver <thomas@kluyver.me.uk> wrote:
On Sun, Jan 27, 2019, at 7:47 PM, Paul Moore wrote:
> What is more difficult is the question of whether the PEP should
> change. As Chris pointed out, the previous discussion ended up saying
> that the build directory should not be on sys.path, but acknowledged
> that mandating that might cause issues. So the question now is, are
> the issues we've seen big enough that we want to change PEP 517 to say
> that the build directory *should* be on sys.path?

I don't see that this issue is an argument for changing the PEP. It seems like a problem with the backend that should be supporting legacy use cases. The rule about the frontend not using the CWD to load the backend doesn't constrain what the backend does once loaded.

From my perspective, the original arguments about the CWD still stand, but in addition PEP 517 is out now and there are tools implementing it, so it would be more disruptive to make changes. So at least for now, I'm -1 on changing the rule about the CWD.