Question about project *

[lorinder]

I have a cabal file containing the build rules depending on quite a number of packages. It looks a bit like this:

executable foo
    main-is:            Main.hs
    build-depends:
        base
      , bytestring
      , gi-gio
      , gi-glib
      , gi-gobject
      , gi-gtk
      , haskell-gi
      , haskell-gi-base
      , network
      , optparse-applicative
      , text
      , mylib

My goal is to have all the dependencies built with -fsplit-sections, so I added a simple cabal.project file, as follows:

packages:
  .

package *
  split-sections: True

My expectation was that this would cause a rebuild of all the dependencies, and, transitively, their dependencies, with that flag enabled. This expectation partly stems from the documentation, section 7.6., that placing those things into the package * section makes them apply to all external dependencies.

However, nothing happens. Doing the change, and running cabal build again seems to do nothing at all. I also tried other modifications, e.g., adding some ghc-options value to the package * section, but that seems to not have an effect, either.

What am I missing? (This is cabal 3.12.1.0 in case it matters.)

[mpickering]

Are you sure that the libraries are not built with split-sections? How are you verifying that?

If you look in the cabal store, you can inspect the cabal-hash.txt which records the options particular store entry was built with.

[nix-shell:~/cabal-regression]$ cat ~/.cabal/store/ghc-9.10.1-9ec8/zlib-0.7.1.0-24b85636be0d9814e7002710bdd5dc18c43a2d23ab18ee773790925a7d0b4f5a/cabal-hash.txt 
pkgid: zlib-0.7.1.0
component: ComponentLib
src: 6edd38b6b81df8d274952aa85affa6968ae86b2231e1d429ce8bc9083e6a55bc
pkg-config-deps: zlib 1.3.1
deps: base-4.20.0.0-7b2c, bytestring-0.12.1.0-3a9c, hsc2hs-0.68.10-e-hsc2hs-c53a4919fea100a55bcd563755ccb411e664098809aad9b9e094263493446790
compilerid: ghc-9.10.1
compilerabi: 9ec8
platform: x86_64-linux
flags: -bundled-c-zlib +non-blocking-ffi +pkg-config
shared-lib: True
stripped-exe: False
debug-info: 0