Reflect rebrand of "preview" to "nightly"

[shonfeder]

A correlate of ocaml-dune/binary-distribution#171

As we prepare to bring milestone https://github.com/ocaml/dune/milestone/62 to a close, we are clarifying the nature of the so called "preview" by rebranding it as merely a nightly binary of dune.

[Leonidas-from-XIV]

Good idea! Found a typo but apart from that its good to go.

[shym]

This looks good to me too (I’ve updated the PR by integrating @Leonidas-from-XIV’s remark and wrapping the commit message).

Shall we also rename dev into nightly?

[Leonidas-from-XIV]

It could be reasonable, to avoid muddying the waters (which is an issue we had with the preview):

• dev I would expect that if some change in Dune is merged, I can run the action and it builds dune and implements the just-merged change.
• nightly I would expect it to use the Dune nightly binary and only updates every, well, night.

[mbarbin]

• dev I would expect that if some change in Dune is merged, I can run the action and it builds dune and implements the just-merged change.

Experimenting with the current tip makes sense to me as a use-case - I wonder then if in this case you may as well call it main? (in some way that's the same conceptually as a tagged version, but using a branch). I am not super confident there, this is just sharing a thought.

[shym]

• nightly I would expect it to use the Dune nightly binary and only updates every, well, night.

Exactly 😄 I added a commit to that effect.

Regarding the build with the current main, I’d imagine that the extra energy and time used to build dune from source is probably not useful to others besides dune developers, so I’d rather not add this (besides the fact this would be far beyond this PR).

[mbarbin]

Regarding the build with the current main, I’d rather not add this (besides the fact this would be far beyond this PR).

That sounds reasonable to me (I was just opining on the name if anything). Having the repo fetch pre-compiled binaries only and offering a fast & cached strategy by default is very valuable. Other use cases should probably not be advertised, if anything to encourage sparse use of CI resources, etc.

Exciting news about dune-pkg MSP getting close!

[Leonidas-from-XIV]

Ok, then I would say that the state of this PR is ok to be merged (modulo some DCO stuff). The dev/main thing can be added in a separate PR if there's interest.

[shym]

Ok, then I would say that the state of this PR is ok to be merged

Great! I’ll give some time to Shon to chip in about the changes and merge if that’s ok with him.

[shonfeder]

Sorry for missing this. The changes look fine to me!