Viktor Dukhovni writes:

Just, for example:

$ cabal install --constraint "cabal-install ^>= 3.4" cabal-install

This fails due to a conflict between Cabal-3.4 and Cabal-syntax-3.10, (which is not the right choice of dependency for Cabal 3.4).

The hackage dependency data looks wrong, the "cabal-syntax" flag in "hackage-security" should not default to "on", and then an older version of "Cabal-syntax" would be chosen.

Which GHC version are you attempting to build with? My guess is that `cabal-install-3.4` excludes your GHC's `base` via its version constraints. Cheers, - Ben

On Sat, Nov 25, 2023 at 05:23:33PM -0500, Viktor Dukhovni wrote:

...

Which GHC version are you attempting to build with? My guess is that `cabal-install-3.4` excludes your GHC's `base` via its version constraints.

No, I'm specifically using GHC 8.10, which actually comes with the Cabal 3.4 library. Also tried 8.8 with same results.

Here's the build output: $ ghc --version The Glorious Glasgow Haskell Compilation System, version 8.8.4 $ cabal --version cabal-install version 3.0.1.0 compiled using version 3.0.1.0 of the Cabal library $ cabal install --constraint 'cabal-install ^>=3.4' cabal-install Resolving dependencies... Build profile: -w ghc-8.8.4 -O1 In order, the following will be built (use -v for more details): - Cabal-3.4.1.0 (lib) (requires build) - Cabal-syntax-3.10.2.0 (lib) (requires build) ... - hackage-security-0.6.2.3 (lib) (requires build) ... - cabal-install-3.4.1.0 (exe:cabal) (requires build) ... Installing Cabal-syntax-3.10.2.0 (lib) Completed Cabal-syntax-3.10.2.0 (lib) Starting hackage-security-0.6.2.3 (lib) Building hackage-security-0.6.2.3 (lib) Installing hackage-security-0.6.2.3 (lib) Completed hackage-security-0.6.2.3 (lib) Installing Cabal-3.4.1.0 (lib) Completed Cabal-3.4.1.0 (lib) Starting cabal-install-3.4.1.0 (exe:cabal) Building cabal-install-3.4.1.0 (exe:cabal) Failed to build exe:cabal from cabal-install-3.4.1.0. Build log ( /home/viktor/.cabal/logs/ghc-8.8.4/cabal-install-3.4.1.0-0f55dc0aa499748357ddf42c4e32b1e210d53da7ef90484735d9a77309f7612d.log ): Configuring executable 'cabal' for cabal-install-3.4.1.0.. Preprocessing executable 'cabal' for cabal-install-3.4.1.0.. Building executable 'cabal' for cabal-install-3.4.1.0.. [ 1 of 180] Compiling Distribution.Client.Compat.Directory ( Distribution/Client/Compat/Directory.hs, dist/build/cabal/cabal-tmp/Distribution/Client/Compat/Directory.o ) [ 2 of 180] Compiling Distribution.Client.Compat.ExecutablePath ( Distribution/Client/Compat/ExecutablePath.hs, dist/build/cabal/cabal-tmp/Distribution/Client/Compat/ExecutablePath.o ) ... [128 of 180] Compiling Distribution.Client.FetchUtils ( Distribution/Client/FetchUtils.hs, dist/build/cabal/cabal-tmp/Distribution/Client/FetchUtils.o ) Distribution/Client/FetchUtils.hs:195:36: error: • Couldn't match type ‘Distribution.Types.PackageId.PackageIdentifier’ with ‘Cabal-syntax-3.10.2.0:Distribution.Types.PackageId.PackageIdentifier’ NB: ‘Cabal-syntax-3.10.2.0:Distribution.Types.PackageId.PackageIdentifier’ is defined in ‘Distribution.Types.PackageId’ in package ‘Cabal-syntax-3.10.2.0’ ‘Distribution.Types.PackageId.PackageIdentifier’ is defined in ‘Distribution.Types.PackageId’ in package ‘Cabal-3.4.1.0’ Expected type: Cabal-syntax-3.10.2.0:Distribution.Types.PackageId.PackageIdentifier Actual type: PackageId • In the second argument of ‘Sec.downloadPackage'’, namely ‘pkgid’ In a stmt of a 'do' block: Sec.downloadPackage' rep pkgid path In the second argument of ‘($)’, namely ‘do info verbosity ("Writing " ++ path) Sec.downloadPackage' rep pkgid path’ | 195 | Sec.downloadPackage' rep pkgid path | ^^^^^ cabal: Failed to build exe:cabal from cabal-install-3.4.1.0. See the build log above for details. -- Viktor.