Build with aeson >= 2.0

[jneira]

• I am continuing @Anton-Latukha's work from try enable brittany #2473 in this branch https://github.com/jneira/haskell-language-server/tree/brittany-9.0.1

• As the new version of brittany needs aeson >= 2.0 we have to jump into that wagon (or patch brittany to support aeson <= 2.0 and ghc-9.0.1 at same time)

• So we have to go down the rabbit hole to get aeson-2 for ghc >= 9.01:

  • Support aeson >= 2.0 ennocramer/floskell#68
  • On Hackage lsp-types release restricts to aeson <1.6 lsp#373
  • Add support for aeson >= 2.0 stylish-haskell#387

• Upstream brittany deps which need support for ghc-9.0.1 (so needed to make available brittany+9.0.1 in hackage)

  • multistate: Allow base 4.15 lspitzner/multistate#8
  • data-tree-print: Allow base < 4.17 and ghc <= 9.2.1 lspitzner/data-tree-print#3
  • butcher: Support for base-4.15 and ghc-9.0.* lspitzner/butcher#8

• Needed to support aeson-2 for ghc < 9.0.1 (not mandatory)

  • Consider backport support for extras >=1.7.10 and aeson >= 2.0 to hlint-3.2 ndmitchell/hlint#1328
  • Brittany support for aeson-2.0 + ghc < 9.0.1

[jneira]

Of course floskell is not buildable with aeson >= 2.0:

src/Floskell/ConfigFile.hs:93:26: error:
Error:     • Couldn't match type: HashMap.HashMap k0 JSON.Value
                     with: Data.Aeson.KeyMap.KeyMap JSON.Value
      Expected: JSON.Object
        Actual: HashMap.HashMap k0 JSON.Value
    • In the first argument of ‘JSON.Object’, namely
        ‘(HashMap.unionWith mergeJSON l r)’
      In the expression: JSON.Object (HashMap.unionWith mergeJSON l r)
      In an equation for ‘mergeJSON’:
          mergeJSON (JSON.Object l) (JSON.Object r)
            = JSON.Object (HashMap.unionWith mergeJSON l r)
   |
93 |             JSON.Object (HashMap.unionWith mergeJSON l r)
   |                          ^^^^^^^^^^^^^^^

[jneira]

or patch brittany to support aeson <= 2.0 and ghc-9.0.1 at same time

given aeson >= 2.0 inlcudes an important security related patch i think we should try to use it here

[jneira]

PR to add aeson >= 2.0 to floskell: ennocramer/floskell#69

[jneira]

hls-plugin-api needs to be patched, several errors like:

src\Ide\Plugin\Properties.hs:240:25: error:
Error:     • Couldn't match expected type ‘A.Key’ with actual type ‘T.Text’
    • In the second argument of ‘(A..:)’, namely ‘keyName’
      In a stmt of a 'do' block: txt <- o A..: keyName
      In the expression:
        do txt <- o A..: keyName
           if txt `elem` enumValues then
               pure txt
           else
               fail
                 $ "invalid enum member: "
                     <> show txt <> ". Expected one of " <> show enumValues
    |
240 |           txt <- o A..: keyName

    | 

the fix should be backwards compatible as we have to support libraries with only support for aeson < 2.0 (hlint-3.2) or aeson >= 2.0 (brittany)

[jneira]

After checking master version of lsp packages works with hls, including the test suite, will release new versions

[michaelpj]

I suspect we can sort out hls-plugin-api in a way that works nicely both pre- and post-2.0

[jneira]

I suspect we can sort out hls-plugin-api in a way that works nicely both pre- and post-2.0

@michaelpj
haskell/aeson#881 (comment) suggests create a fromKey/toKey and make it work with Text and Aeson.Key using CPP but i would love to do it without cpp conditions (like you did for lsp, using hte Aeson api differently)