PEP 518: Use build isolation only for "modern" sdists

[pradyunsg]

Currently, the PEP 518 support in pip does every wheel build in isolation -- at least as per my understanding -- and this is not correct. This would break a lot of existing packages and we don't want to do that.

The correct behaviour here would be to branch on the "legacy" sdists to run as we did with pip 9 and to run "modern" sdists through the isolation currently in pip master.

I realized this thanks to #5033.

[ghost]

This is not correct, and in addition, not related to gh-5033. This issue should be closed.

[ghost]

pip/src/pip/_internal/operations/prepare.py

Lines 135 to 136 in 34cc364

	if not isolate:
	self.req.build_env = NoOpBuildEnvironment(no_clean=False)

[pradyunsg]

Ah right. I got misdirected by:

pip/src/pip/_internal/wheel.py

Line 629 in 34cc364

isolate=True)

It is indeed unrelated to #5033. I just remembered because of it. =)

[ghost]

Actually, that kwarg should be removed.

[pradyunsg]

Yep. I agree. =)

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.