pip install should crash when an invalid extra/optional dependency is specified

[boyleconnor]

What's the problem this feature will solve?

Pip users can sometimes accidentally mistype the name of an extra/optional dependency (e.g. pip install evaluate[evaluater] instead of pip install evaluate[evaluator]). This currently will lead to the desired extra dependency not being installed, and pip will give a warning to stderr (evaluate 0.4.2.dev0 does not provide the extra 'evaluater') but otherwise continue as normal (including producing a return code of 0).

This can lead to users not noticing that a dependency was not installed.

Describe the solution you'd like

Pip should crash when a user specifies a non-existent extra dependency, just as would be the case with a non-existent top-level package.

Alternative Solutions

I don't believe this section is applicable

Additional context

n/A

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[notatallshaw]

Duplicate of #9736, also similar to #11913 and #7122

I strongly agree, the real world use for extras does not match the wording of the specification and this should be updated. But probably going to have to discuss that with wider packaging community (discuss.python.org) not directly with Pip to get Pip to change it.

[boyleconnor]

Apologies for missing the duplicate. I'll close this issue so all discussion can be concentrated at #9736 or whatever broader Python community discussion this leads to.