On 27 June 2017 at 18:54, Nathaniel Smith <njs@pobox.com> wrote:
On Tue, Jun 27, 2017 at 12:27 AM, Nick Coghlan <ncoghlan@gmail.com> wrote:
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.)
No, both `get_build_wheel_requires()` and `build_wheel()` also have to work in-place - backends aren't allowed to assume that *all* builds will be out-of-tree, even though pip specifically is expected to work that way. Neither of these hooks is allowed to give different results depending on whether you're doing an in-place or out-of-tree build. To put it another way, there are two build paths that backends are required to support: - in-place, direct from the original source tree - out-of-tree, from an unpacked sdist There's also a third, optional, build path for backends that define `prepare_wheel_input_files`: - out-of-tree, from a prepared wheel input directory The result wheel should be "the same" regardless of how the build is executed. In practice, we expect there will be some variation, just because reproducible builds are hard. However, the output of the different paths should be at least as similar as any two builds of the same source tree run at different times with the same system configuration. Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia