On 2018-07-08 10:31:04 -0700 (-0700), Nathaniel Smith wrote: [...]
Unless I'm missing something, that's unrelated :-). The "build isolation" we're talking about here is a new feature where pip tries to use a clean python environment for the build, and that issue is about an old feature where pip tries to use a clean copy of the source directory for the build.
Ahh, yes, apologies! I had incorrectly assumed the new build environment isolation was also going to have changes to build directory isolation.