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Description
This is a longer-term goal, not something that can be done without a carefully managed transition, but pip should remove support for building and installing packages without using PEP 517.
Before this can be done, we need to be sure that PEP 517 support is complete, and there are no edge cases remaining of projects that cannot build with PEP 517, but need the legacy path. There is also an open question on how we provide editable install support, which is not covered by PEP 517.
I have raised this issue so that we have a central point to link to which makes it clear that this is the intended long term goal.