On Tue, Jun 27, 2017 at 12:27 AM, Nick Coghlan <ncogh...@gmail.com> wrote: > On 26 June 2017 at 22:36, Nathaniel Smith <n...@pobox.com> wrote: >> On Jun 25, 2017 12:46 AM, "Nick Coghlan" <ncogh...@gmail.com> wrote: >> >> On 25 June 2017 at 17:41, Nathaniel Smith <n...@pobox.com> wrote: >>> Maybe you're right and there are exactly 2 front-end use cases and it >>> will turn out that the current PEP addresses them perfectly. I don't >>> have a crystal ball; I'm making an argument from ignorance. >> >> I'm not - we have two concrete potential consumers of the interface >> (pip and tox, aka "build to use" and "build to test"), and I'm >> designing the interface to cover their needs (i.e. out-of-tree wheel >> builds and actual sdists). >> >> If we discover other use cases later, we'll worry about them then (and >> the easy of doing so is the nicest benefit of defining this as a >> Python API), but the temptation to design in hyper-flexibility now >> falls under YAGNI (You Ain' Gonna Need It). >> >> >> My proposal also covers their needs AFAICT? > > No, as you don't know in your proposal whether or not build_sdist can > fail until after you've already called it, and you always need to call > both `get_build_sdist_requires()` and `build_sdist()`, even if you > only care about doing an out-of-tree wheel build.
Ah, this is an interesting point, thank you! I hadn't thought of that. But... it doesn't seem like a big deal in practice? If a build backend knows that it can't build an sdist from a given tree, then its get_build_sdist_requires hook (which is arbitrary code after all) can surely figure this out and return []. Or we could allow get_build_sdist_requires to also return NotImplemented (defining that to mean "building sdists is not implemented, don't even try calling build_sdist"), though maybe that's unnecessary fiddliness. > 2. If you don't find the input preparation hook: > > - call `get_build_sdist_requires()` > - call `get_build_wheel_requires()` > - install both sets of additional dependencies > - call `build_sdist()` > - unpack the sdist into the build directory > - call `build_wheel()` Side note: I think this is wrong -- I think you can't call get_build_wheel_requires until after you've unpacked the sdist, because that's a whole new tree that might be arbitrarily different. (In practice I guess this should never happen, but we should be clear conceptually I think.) -n -- Nathaniel J. Smith -- https://vorpus.org _______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org https://mail.python.org/mailman/listinfo/distutils-sig
