bpo-31351: Fix RC 0 in ensurepip when pip fails

[iafilatov]

ensurepip discards pip's return code which leads to broken venvs. Make sure EC is propagated to that scripts that run ensurepip in a separate process (e.g. python -m ensurepip) can detect failure.

I decided to keep the return value of the public version of bootstrap() unmodified although I'm not sure it's correct because it leaves no way to check if pip has succeeded or not (and I doubt there's a lot of code that relies on bootstrap() returning None).

https://bugs.python.org/issue31351

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[ncoghlan]

This looks good to me. Just one additional change needed, which is to mention the command line return value with a corresponding .. versionchanged: 3.7.0 note in https://docs.python.org/3/library/ensurepip.html#command-line-interface

[bedevere-bot]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I didn't expect the Spanish Inquisition!. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[ncoghlan]

As far as the return value of ensurepip.bootstrap() goes, I agree it makes sense to pursue the command-line-only fix first, and then consider changing the Python API in a follow-up patch (since we may decide we want to indicate bootstrap errors with an exception instead of a return value)

[iafilatov]

I didn't expect the Spanish Inquisition!

[bedevere-bot]

Nobody expects the Spanish Inquisition!

@ncoghlan: please review the changes made to this pull request.

[miss-islington]

Thanks @iafilatov for the PR, and @ncoghlan for merging it 🌮🎉.. I'm working now to backport this PR to: 2.7, 3.6.
🐍🍒⛏🤖

[bedevere-bot]

GH-3683 is a backport of this pull request to the 3.6 branch.

[miss-islington]

Thanks @iafilatov for the PR, and @ncoghlan for merging it 🌮🎉.. I'm working now to backport this PR to: 2.7.
🐍🍒⛏🤖

[miss-islington]

Sorry, @iafilatov and @ncoghlan, I could not cleanly backport this to 2.7 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker 9adda0cdf89432386b7a04444a6199b580d287a1 2.7

[bedevere-bot]

GH-3734 is a backport of this pull request to the 2.7 branch.