Update hackage-server for Cabal 3

[bgamari]

This ticket tracks the progress of porting hackage-server to Cabal-3.

[bgamari]

I started working on this a while ago (see https://github.com/bgamari/hackage-server/tree/cabal-3) but admittedly didn't make it very far. The problem was that I wasn't particularly happy with any of the options for rewriting the Pretty and Parsec instances for Day and UTCTime in Distribution.Server.Framework.Instances.

@hvr has also said that he wanted someone to verify that the Binary instances remained compatible (although I'll admit I don't know which Binary instances he was referring to; I don't see any such non-trivial instances in hackage-server).

[bgamari]

Ahh, I see. hackage-server uses cereal's Serialize class, not Binary. This is likely what @hvr was referring to. I compatibility is a concern we should presumably add some golden tests to verify this property before starting on the upgrade.

[bgamari]

PkgConfigVersionRange is unfortunately now a distinct type from VersionRange, which will be problematic in the IsDependency PkgconfigDependency instance.

[phadej]

See hackage-trustees/hackage-cli#13

[tfausak]

I started looking at this too. You can take a look at my branch, but it's still very much a work in progress.

I've spent about a day's worth of work on it so far. I have been having an extremely hard time making the upgrade to Cabal 3. So many things have changed, moved, or been deleted that it's hard to write code that's both backwards and forwards compatible. On top of that, some of the code that is forwards compatible is simply broken, like the Parsec instance for PackageIdentifier.

[tfausak]

I see a bunch of commits were recently pushed to master that seem to start addressing this issue: f3c5eb8, 11136d3, 70de659, b58a7df, 8924eca, add48b9, d003d77. Should I stop working on this?

[tfausak]

I'm not working on this anymore. As far as I can tell, the wip/cabal-3.0 branch is making good headway.

[dwijnand]

Oh. I wasn't aware of this thread or the progress reported here...

I wanted to create such a thread to mark trailing TODOs on the progress being made in wip/cabal-3.0:

• get the code passing on CI: b58d61e
• implement Pretty and Parsec for Time: 088bfed#diff-0251fd4f91872f46f89c3c26c76750b2R241-R242
• implement the flagAssignment field of BuildReport's FieldGrammar: 088bfed#diff-0251fd4f91872f46f89c3c26c76750b2R254

[bgamari]

What remains to be done here, @dwijnand?

[dwijnand]

I'm going to sync up with @hvr on this soon, but it builds already against Cabal 3 (in the wip/cabal-3.0 branch), what's left is upgrading the logic to the changes Cabal 3 brought.

[swamp-agr]

Hello @dwijnand,

I kindly ask you, do you have any news regarding this topic?
Do you know, who is planning to work on the issue?

Thanks,
Andrey

[dwijnand]

No, sorry, no news. I'm not sure who (if anyone) has taken up this task.

[alexbiehl]

@dwijnand can you summarize what's still missing? From the commits on your branch I can see you managed to build hackage with Cabal 3. What's left?