diff options
Diffstat (limited to 'doc/languages-frameworks/haskell.section.md')
| -rw-r--r-- | doc/languages-frameworks/haskell.section.md | 61 |
1 files changed, 53 insertions, 8 deletions
diff --git a/doc/languages-frameworks/haskell.section.md b/doc/languages-frameworks/haskell.section.md index dde55c329a4ac..e363e90854ad3 100644 --- a/doc/languages-frameworks/haskell.section.md +++ b/doc/languages-frameworks/haskell.section.md @@ -923,14 +923,59 @@ for this to work. `justStaticExecutables drv` : Only build and install the executables produced by `drv`, removing everything -that may refer to other Haskell packages' store paths (like libraries and -documentation). This dramatically reduces the closure size of the resulting -derivation. Note that the executables are only statically linked against their -Haskell dependencies, but will still link dynamically against libc, GMP and -other system library dependencies. If dependencies use their Cabal-generated -`Paths_*` module, this may not work as well if GHC's dead code elimination -is unable to remove the references to the dependency's store path that module -contains. + that may refer to other Haskell packages' store paths (like libraries and + documentation). This dramatically reduces the closure size of the resulting + derivation. Note that the executables are only statically linked against their + Haskell dependencies, but will still link dynamically against libc, GMP and + other system library dependencies. + + If the library being built or its dependencies use their Cabal-generated + `Paths_*` module, this may not work as well if GHC's dead code elimination is + unable to remove the references to the dependency's store path that module + contains. (See [nixpkgs#164630][164630] for more information.) + + Importing the `Paths_*` module may cause builds to fail with this message: + + ``` + error: output '/nix/store/64k8iw0ryz76qpijsnl9v87fb26v28z8-my-haskell-package-1.0.0.0' is not allowed to refer to the following paths: + /nix/store/5q5s4a07gaz50h04zpfbda8xjs8wrnhg-ghc-9.6.3 + ``` + + If that happens, first disable the check for GHC references and rebuild the + derivation: + + ```nix + pkgs.haskell.lib.overrideCabal + (pkgs.haskell.lib.justStaticExecutables my-haskell-package) + (drv: { + disallowGhcReference = false; + }) + ``` + + Then use `strings` to determine which libraries are responsible: + + ``` + $ nix-build ... + $ strings result/bin/my-haskell-binary | grep /nix/store/ + ... + /nix/store/n7ciwdlg8yyxdhbrgd6yc2d8ypnwpmgq-hs-opentelemetry-sdk-0.0.3.6/bin + ... + ``` + + Finally, use `remove-references-to` to delete those store paths from the produced output: + + ```nix + pkgs.haskell.lib.overrideCabal + (pkgs.haskell.lib.justStaticExecutables my-haskell-package) + (drv: { + postInstall = '' + ${drv.postInstall or ""} + remove-references-to -t ${pkgs.haskellPackages.hs-opentelemetry-sdk} + ''; + }) + ``` + +[164630]: https://github.com/NixOS/nixpkgs/issues/164630 `enableSeparateBinOutput drv` : Install executables produced by `drv` to a separate `bin` output. This |