Relax lens lower bound

[endgame]

servant-multipart-0.11.3 depends on lens >= 4.17 && < 4.18, while the previous version depended on lens >= 4.0 && < 4.18.

servant-multipart uses four functions from Control.Lens, and looking at the lens changelog none of them seem to have recent changes to behaviour. Can the lower bound please be relaxed, and a metadata revision pushed to hackage?

(Among other things, this is currently breaking installing servant-multipart via nixpkgs on darwin.)

[alpmestan]

Thanks for reporting this issue!

Sure thing, I'll make a revision on hackage and reflect it in the repo later this morning (got to run right now).

[phadej]

I wonder how nixpkgs is broken.

Also note that latest servant-foreign also requires lens >= 4.17.

[alpmestan]

@endgame Hmm I just checked and the latest lens release is 4.17, which is included in both the previous version range and the one for servant-multipart-0.11.3, so I'm not sure exactly what the new bounds should be, and what the problem is. Could you show us the error message?

[endgame]

The version of lens currently in nixpkgs on my GNU/Linux and macOS/darwin machines both have lens-4.16.1.

Also, is servant-multipart using 0.15 specific features from {servant, servant-foreign, servant-server}? Those are also not currently in nixpkgs.

nixpkgs master has lens-4.17, so this is not especially pressing, but it would be nice to have since it's not using recent lens features.

[alpmestan]

Aaaaah, so we're requiring too recent a lens version...

[endgame]

Yes. From memory you're using view, (&), (.~) and (<>~), all of which have been around for a long time.

[phadej]

Note to self: lens-4.17 was uploaded at Tue Jul 3 17:05:19 UTC 2018; i.e. 6 months ago.
servant-multipart-0.11.3 at Tue Nov 13 22:03:02 UTC 2018, ~two months ago.

I'm really confused. Why you can upgrade to servant-multipart but cannot upgrade lens?
I'd rather poke at people maintaining packages with restricting upper bounds (I recall Chart at least has lens < 4.17 and other stuff)

[endgame]

At the time I reported this, nixpkgs on darwin had lens-4.16 and servant-multipart-0.11.3, and I was chasing build failures.

nixpkgs on my GNU/Linux machine is still giving me lens-4.16 but servant-multipart-0.11.2, so it builds.