Yes vendoring would be a solution but it's too soon to say whether the problem is significant. Setuptools and pip have a different problem which is that the package manager isn't available yet. In pep517 the package manager is available.
On Sat, Jul 29, 2017, 17:50 Alex Grönholm <alex.gronh...@nextday.fi> wrote: > Daniel Holth kirjoitti 30.07.2017 klo 00:48: > > I think the proposal is that flit depends on click depends on flit and > neither one has a wheel and must be built from sdists. Then you have a > circular build problem. So don't do that. I put this in the same category > as accidentally conflicting with a stdlib module; it is confusing when it > happens but it's also fairly avoidable. > > Sure but vendorizing the dependencies would work around the problem, yes? > Like how setuptools does? > > > On Sat, Jul 29, 2017, 17:38 Alex Grönholm <alex.gronh...@nextday.fi> > wrote: > >> Donald Stufft kirjoitti 29.07.2017 klo 23:47: >> >> >> On Jul 29, 2017, at 12:46 PM, Nathaniel Smith <n...@pobox.com> wrote: >> >> I guess the most obvious example of when this would occur is: suppose >> click switches to using flit for builds, and then flit switches to using >> click for command line parsing. Now there's a bit of a chicken and egg >> problem where 'pip install click' will end up importing flit with the click >> source tree on the path, and this tree of course contains a directory named >> 'click', so unless special measures are taken flit will end up importing >> the code it's trying to build. >> >> But of course this can happen for lots of reasons; most packages have >> names that you wouldn't expect to randomly encounter at the root of a >> source tree very often, but with 100,000+ packages on pypi I expect it will >> happen eventually. >> >> This doesn't happen with setuptools because setuptools traditionally has >> few or no dependencies, but obviously we're changing that; the whole idea >> here is that now your build system has full access to pypi. >> >> >> >> This is something to be discouraged anyways, because it creates a sort of >> broken situation (the same situation that setuptools itself had). The >> problem is that if you’re starting from only sdists, you have a circular >> dependency that cannot be broken. You can’t build click, because click >> requires flit, but you can’t install flit, because flit requires click. The >> only way to fix this is to either have an already built wheel that you can >> use (which obviously was either built with a flit that didn’t require >> click, or a click that didn’t require flit, or it’s provenance can be >> traced back to that) or do some hacks that will hopefully resolve the >> situation good enough to get your first wheel built. >> >> Setuptools tried to depend on things, and it broke shit for a lot of >> people because of this. You basically can’t depend on anything as a build >> system that uses you as a build system. You can only depend on things that >> use other, different build systems in the entire dependency tree. Likely >> the best thing for build systems to do is either have no dependencies, or >> to have minimal dependencies that promise to only use setuptools (or >> another build tool, which one doesn’t matter, just as long as it has no >> dependencies) forever (and have setuptools or this other build tool promise >> to never take a dependency). >> >> Or vendorize their dependencies? To me it seems unrealistic for a build >> system to have no dependencies at all. Or perhaps this is exactly what you >> meant :) >> >> >> — >> Donald Stufft >> >> >> >> >> >> _______________________________________________ >> Distutils-SIG maillist - >> Distutils-SIG@python.orghttps://mail.python.org/mailman/listinfo/distutils-sig >> >> >> _______________________________________________ >> Distutils-SIG maillist - Distutils-SIG@python.org >> https://mail.python.org/mailman/listinfo/distutils-sig >> > >
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