Switch from readline to haskeline

[joncol]

Apparently readline doesn't build with newer versions of cabal.

[arybczak]

How come? I can build it just fine with cabal-3.12.1.0 and GHC 9.10.1 locally 🤔 Where's the error?

[arybczak]

I'm necessarily opposed to the idea of replacing readline with haskeline btw, I'm just wondering what's the error you're getting though, because I'm not getting it.

[arybczak]

Although I see haskeline has strict dependency bounds and readline doesn't, so the latter is most likely less annoying to deal with when testing new GHC versions.

[joncol]

How come? I can build it just fine with cabal-3.12.1.0 and GHC 9.10.1 locally 🤔 Where's the error?

Can you also run cabal build hpqtypes-tests without problems?

I'm on:

➜ ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.6.6
~/work/scrive/hpqtypes (master) ✗
➜ cabal --version
cabal-install version 3.12.1.0
compiled using version 3.12.1.0 of the Cabal library

[joncol]

To be clear, the full error I'm seeing is this:

➜ cabal build hpqtypes-tests
Build profile: -w ghc-9.6.6 -O1
In order, the following will be built (use -v for more details):
 - readline-1.0.3.0 (lib:readline) (requires download & build)
 - hpqtypes-1.12.0.0 (test:hpqtypes-tests) (configuration changed)
Downloading  readline-1.0.3.0
Downloaded   readline-1.0.3.0
Starting     readline-1.0.3.0 (all, legacy fallback: build-type is Configure cabal-version is less than 1.8)

Failed to build readline-1.0.3.0. The failure occurred during the configure
step.
Build log (
/home/jco/.cache/cabal/logs/ghc-9.6.6/readline-1.0.3.0-f7e7ddbf6183a73d4de473c70156ea933231f0968c5c058d277648afe74b2733.log
):
Warning: readline.cabal:27:32: version operators used. To use version
operators the package needs to specify at least 'cabal-version: >= 1.8'.
Warning: readline.cabal:9:1: Tabs used as indentation at 9:1, 10:1, 12:1,
13:1, 15:1, 16:1
Configuring readline-1.0.3.0...
checking for gcc... /nix/store/zznja5f8v3jafffyah1rk46vpfcn38dv-gcc-wrapper-13.3.0/bin/cc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether /nix/store/zznja5f8v3jafffyah1rk46vpfcn38dv-gcc-wrapper-13.3.0/bin/cc accepts -g... yes
checking for /nix/store/zznja5f8v3jafffyah1rk46vpfcn38dv-gcc-wrapper-13.3.0/bin/cc option to accept ISO C89... none needed
checking for GNUreadline.framework... checking for readline... no
checking for tputs in -lncurses... yes
checking for readline in -lreadline... no
checking for rl_readline_version... no
configure: error: readline not found, so this package cannot be built
See `config.log' for more details.
Error: [Cabal-7125]
Failed to build readline-1.0.3.0 (which is required by test:hpqtypes-tests from hpqtypes-1.12.0.0). See the build log above for details.

[joncol]

And when I try to add readline package to my system, I get the following build error:

error: builder for '/nix/store/hbjy5pw2fkg09a8w8gy0i25l736pr20x-readline-1.0.3.0-setup.drv' failed with exit code 1;
       last 15 log lines:
       > Running phase: unpackPhase
       > unpacking source archive /nix/store/fsi8nmsvz677plwqjyd7b6h084mx4bkg-readline-1.0.3.0.tar.gz
       > source root is readline-1.0.3.0
       > setting SOURCE_DATE_EPOCH to timestamp 1361098403 of file readline-1.0.3.0/readline.cabal
       > Running phase: patchPhase
       > Running phase: buildPhase
       > Compiling package Setup.hs
       > Loaded package environment from /nix/store/qlflxpz6cn4bvqx6hn6kk6mfcgph2c04-readline-1.0.3.0-setup-configFiles/ghc-environment
       > [1 of 2] Compiling Main             ( Setup.hs, Setup.o )
       >
       > Setup.hs:6:29: error: [GHC-88464]
       >     Variable not in scope: defaultUserHooks :: UserHooks
       >   |
       > 6 | main = defaultMainWithHooks defaultUserHooks
       >   |                             ^^^^^^^^^^^^^^^^
       For full logs, run 'nix log /nix/store/hbjy5pw2fkg09a8w8gy0i25l736pr20x-readline-1.0.3.0-setup.drv'.

Then I saw this: https://stackoverflow.com/a/67521967/278903

Maybe it's just an issue on my system :/.

[arybczak]

If you install the readline C library (or make it available in your nix-shell or something), cabal build hpqtypes-tests should successfully install readline, the Haskell package.

[joncol]

If you install the readline C library (or make it available in your nix-shell or something), cabal build hpqtypes-tests should successfully install readline, the Haskell package.

Installing the readline library doesn't seem to help.

Probably, it's my Nix configuration going wrong. I think the problem I'm running into is that Setup.hs of the readline-1.0.3.0 source contains the following:

main :: IO ()
main = defaultMainWithHooks defaultUserHooks

And that defaultUserHooks was apparently deprecated a long time ago, so I get a build error for it. https://hackage.haskell.org/package/Cabal-2.0.1.0/docs/src/Distribution-Simple.html has the following note:

{-# DEPRECATED defaultUserHooks
     "Use simpleUserHooks or autoconfUserHooks, unless you need Cabal-1.2\n             compatibility in which case you must stick with defaultUserHooks" #-}

Maybe there's some way to specify the Cabal version to use for a specific library that I don't know about.

But this is really not that important really, so feel free to close this PR. Your call :).