Disallow runs of special characters in project names

[dstufft]

It should not be allowed to upload a project named something like foo--bar. It creates hard to read project names.

[dstufft]

Here's a SQL query that will return a list of projects that currently use a run of special characters:

SELECT *
FROM (
    SELECT name,
           regexp_replace(name, '[_.]', '-', 'g') as dname,
           regexp_replace(name, '[-_.]+', '-', 'g') as rname
    FROM packages
) as s
WHERE dname != rname;

There are currently 13, we should reach out to them and see if they'd mind dropping any runs of special characters so we can enforce this easily in the database. There shouldn't be any issues with collisions or such since the normalization already eliminates runs of special characters.

[brainwane]

We discussed this idea in the Warehouse meeting today -- I presume that the change would be just for readability?

I'm marking it blocked since implementing it would require PEPs to be modified. And since this is a new change that doesn't get us closer to replacing legacy PyPI I've added it to a far future milestone.