Add packer nightly formula

[sylviamoss]

This adds the packer nightly releases. The nightly releases are updated every 7 days.

I haven't tested the formula and would like some help with it.

[samsalisbury]

Hi @sylviamoss, I think this PR should include an update to util/formula_templater/config.hcl to add a template for packer-nightly but I’m not 100% if that supports conflicts_with and/or version "nightly".. I'll requests a review from @kpenfound as I think he will be in a better position to help with this hopefully!

[sylviamoss]

Got it! Thank you @samsalisbury

[azr]

Would it be a possibility and a good idea to rename the binary to packer-nightly here ? 🤔

[radeksimko]

Just to add some context here, Homebrew unfortunately doesn't have any decent/clean way of supporting multiple versions and we have in the past avoided adding these - see also #79

That said I'm certainly not in a position to say this is still a current stance and that it applies specifically to nightly releases, I'm merely adding the context.

If you are going ahead with this as a separate formula I would suggest change the class name to something unique - e.g. PackerNightly, otherwise I think that the whole tap will break for everyone due to duplicate classes.

Secondly you may want to consider making the version stanza something unique as well - the static value ("nightly") otherwise prevents Homebrew from performing upgrades. You could in theory set it to :latest, if you want to avoid updating the formula with every nightly release. The trade-off is that users would have to use brew upgrade --greedy-latest to upgrade that formula. That :latest symbol is more often used for auto-updating software, such as Chrome though.

The conflicts_with should be fine here, but I am not sure that it does what you think it does. AFAIK that stanza always refers to core formulas, not formulas in a tap, i.e. conflicts_with "packer" refers to https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/packer.rb

As for the binary name - I don't have too strong opinion on this, but it seems that the convention in the wild is to retain the name used for all other versions as opposed to adding the version there.

See also https://github.com/Homebrew/linuxbrew-core/blob/HEAD/Formula/[email protected] for inspiration.

[sylviamoss]

Thanks @radeksimko for the context. Know that I decided not to move forward with this. It makes sense to download non-stable nightly releases only from GitHub and making it explicit about it.