A pip sdist command

[konstin]

What's the problem this feature will solve?
PEP 517 defines build_wheel and build_sdist to build a wheel and a source distribution respectively. build_wheel can be used through pip wheel, while build_sdist is not available through the cli, even though the frontend part is already implemented.

Describe the solution you'd like
A pip sdist command akin to pip wheel, which take the path to a local project path or a vcs project url and builds a source distribution.

This was originally proposed in #1323, which was closed with the comment that "[...] we're probably going to want a command like this when we get abstract build systems [...]".

My reason for resurrecting this is this issue comment. The idea is to verify that the source distribution is complete in a build backend independent fashion, i.e. run pip sdist . && pip install myproject-1.2.3.tar.gz in ci.

Alternative Solutions

The pip build command from #6041. If pip build deprecates pip wheel I'd be happy about that, otherwise I believe would still be a good idea to a pip sdist that is symmetric to pip wheel.

Additional context

Thread with some additional discussion: pypa/packaging-problems#219

[pradyunsg]

There's an idea for a pip build command. See #6041. We will deprecate pip wheel if we go that route.

Closing as a duplicate since the build command would minimize the size of pip's CLI in terms of commands, and since I strongly prefer that anyway. :)

Thanks for filing this!