github_packages: fix versioned bottle names.

[MikeMcQuaid]

@ cannot be used in Docker image names. Use AT instead (which we already use in class names so has some precedent).

Make mktemp consistent, too.

[BrewTestBot]

Review period skipped due to critical label.

[sjackman]

Name components may contain lowercase letters, digits and separators. A separator is defined as a period, one or two underscores, or one or more dashes. A name component may not start or end with a separator.

https://docs.docker.com/engine/reference/commandline/tag/

Upper case letters are not permitted in name components. Good idea otherwise!

[sjackman]

How about a single hyphen or underscore? gcc-10 has a nice ring to it.

$ ls *-[0-9]*.rb
ntfs-3g.rb pyqt-3d.rb
$ ls *-[0-9].rb
zsh: no matches found: *-[0-9].rb

I am actually surprised that no formulae match .*-[0-9].rb

[mistydemeo]

That still leaves slight ambiguity in parsing, but if we don't have any formulae that meet that pattern we're probably safe. Doesn't look like there are any third-party tap packages in formulae.brew.sh that suggests we'll probably be fine. We might want to think about writing an audit just for the main tap to ensure we don't accidentally commit formulae that would clash with another one?

[MikeMcQuaid]

Like @mistydemeo I’d rather figure out something unambiguous in parsing. We already use single dash, double dash, single underscore, single period as separators. We don’t use double underscores so I’d propose one of those.

Another slightly off the wall option that would be permitted would be gcc/10. Definitely no risk of clashing in that case and given we’re already doing core/gcc then core/gcc/10 feels like it makes sense. The more I think about this the more I like it. Thoughts?

Using valid character

[MikeMcQuaid]

@sjackman 👍🏻 d in Slack.

[mistydemeo]

I feel a little weird about / just because it looks like the org/repo divider in fully-qualified formula names. Not actually ambiguous in this context, just looks kind of weird. I'd slightly prefer a double underscore but I don't think it's too critical.