Thanks, @ncoghlan. To clarify, in your suggestion are there any combinations or scenarios where either an error should be raised or a warning logged in current pip?
Also, is there any concern that when it comes time to standardizing editable mode, we won’t be able to (or for some reason might not want to) match setuptools’ current behavior using backends, in which case we would have to break compatibility in some other, possibly bigger way at a later date to make the API work?
Some people on the tracker were suggesting the use of a different flag / option name for the future PEP 517-defined editable mode (e.g. --develop, --source-install, --inplace, etc. as opposed to --editable). With the seamless approach you described, you’re saying no new option name would be needed in the future?