From c2ffd1f4a80efa1872c97c5ea6f3e1b692d7110f Mon Sep 17 00:00:00 2001
From: Rebecca Turner <rbt@sent.as>
Date: Mon, 9 Jun 2025 15:25:39 -0700
Subject: [PATCH] haskell.packages.*.ghcWithPackages: Fix on darwin

Previously, `ghcWithPackages` would fail to build on macOS because
package `.conf` files now contain a literal `${pkgroot}` (which of
course does not exist):

```
$ grep -Poz "dynamic-library-dirs:\s*\K .+\n" /nix/store/s5xrmb3583fd5qjrqsg73fblaq46gqpd-ghc-9.10.1-with-packages/lib/ghc-9.10.1/lib/package.conf.d/*
...
/nix/store/s5xrmb3583fd5qjrqsg73fblaq46gqpd-ghc-9.10.1-with-packages/lib/ghc-9.10.1/lib/package.conf.d/unix-2.8.5.1-ce1b.conf.copy: ${pkgroot}/../lib/aarch64-osx-ghc-9.10.1
...
```

Therefore, we use `ghc-pkg --simple-output list` to get a list of
`.conf` files and `ghc-pkg --simple-output field "$pkg"
dynamic-library-dirs` to get the value of the field while expanding
`${pkgroot}` prefixes.
---
 .../haskell-modules/with-packages-wrapper.nix | 22 ++++++++-----------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/pkgs/development/haskell-modules/with-packages-wrapper.nix b/pkgs/development/haskell-modules/with-packages-wrapper.nix
index d1b8aeebf4f8..528c87fef4b9 100644
--- a/pkgs/development/haskell-modules/with-packages-wrapper.nix
+++ b/pkgs/development/haskell-modules/with-packages-wrapper.nix
@@ -62,13 +62,6 @@ let
     else
       "$out/lib/${ghc.targetPrefix}${ghc.haskellCompilerName}"
       + lib.optionalString (ghc ? hadrian) "/lib";
-  # Boot libraries for GHC are present in a separate directory.
-  bootLibDir =
-    let
-      arch = if stdenv.targetPlatform.isAarch64 then "aarch64" else "x86_64";
-      platform = if stdenv.targetPlatform.isDarwin then "osx" else "linux";
-    in
-    "${ghc}/lib/${ghc.haskellCompilerName}/lib/${arch}-${platform}-${ghc.haskellCompilerName}";
   docDir = "$out/share/doc/ghc/html";
   packageCfgDir = "${libDir}/package.conf.d";
   paths = lib.concatLists (
@@ -154,14 +147,17 @@ else
           # symlinkJoin:
           rm -f $dynamicLinksDir/*
 
-          # Boot libraries are located differently than other libraries since GHC 9.6, so handle them separately.
-          if [[ -x "${bootLibDir}" ]]; then
-            find "${bootLibDir}" -name '*.dylib' -exec ln -s {} "$dynamicLinksDir" \;
-          fi
+          dynamicLibraryDirs=()
 
-          for d in $(grep -Poz "dynamic-library-dirs:\s*\K .+\n" $packageConfDir/*|awk '{print $2}'|sort -u); do
-            find "$d" -name '*.dylib' -exec ln -s {} "$dynamicLinksDir" \;
+          for pkg in $($out/bin/ghc-pkg list --simple-output); do
+            dynamicLibraryDirs+=($($out/bin/ghc-pkg --simple-output field "$pkg" dynamic-library-dirs))
           done
+
+          for dynamicLibraryDir in $(echo "''${dynamicLibraryDirs[@]}" | tr ' ' '\n' | sort -u); do
+            echo "Linking $dynamicLibraryDir/*.dylib from $dynamicLinksDir"
+            find "$dynamicLibraryDir" -name '*.dylib' -exec ln -s {} "$dynamicLinksDir" \;
+          done
+
           for f in $packageConfDir/*.conf; do
             # Initially, $f is a symlink to a read-only file in one of the inputs
             # (as a result of this symlinkJoin derivation).