Nix: Wrap GHC and HLS, specifically, to provide (DY)?LD_LIBRARY_PATH.

We clearly do need this environment variable (at least on macOS); otherwise GHC spits out a slew of errors along the lines of "cannot find libodbc.dylib".

However, adding it directly to the shell causes serious problems. Wrapping GHC should limit the damage.

We've seen similar issues on macOS.

PR-URL: hasura/graphql-engine-mono#9203
Co-authored-by: Philip Lykke Carlsen <[email protected]>
GitOrigin-RevId: 9468d31e5b8ec86196809844842a1668386054bc

Author: 2 people

flake.nix

@@ -39,7 +39,7 @@
 
       formatter = pkgs.nixpkgs-fmt;
 
-      devShells.default = import ./nix/shell.nix { inherit pkgs; };
+      devShells.default = import ./nix/shell.nix { inherit pkgs system; };
     }
     );
 }

nix/shell.nix

@@ -1,7 +1,14 @@
-{ pkgs }:
+{ pkgs, system }:
 let
   versions = import ./versions.nix { inherit pkgs; };
 
+  # empty package, for shenanigans
+  empty = builtins.derivation {
+    inherit system;
+    name = "empty";
+    builder = pkgs.writeShellScript "null.sh" "${pkgs.coreutils}/bin/mkdir $out";
+  };
+
   # Unix ODBC Support
   freetdsWithODBC = pkgs.freetds.override {
     odbcSupport = true;
@@ -28,6 +35,40 @@ let
     configureFlags = [ "--disable-gui" "--sysconfdir=${odbcConfiguration}" ];
   });
 
+  # Ensure that GHC and HLS have access to all the dynamic libraries we have kicking around.
+  ghc =
+    let original = pkgs.haskell.compiler.${pkgs.ghcName};
+    in pkgs.stdenv.mkDerivation
+      {
+        name = original.name;
+        src = empty;
+        buildInputs = [ original pkgs.makeWrapper ];
+        installPhase = ''
+          mkdir -p "$out/bin"
+          makeWrapper ${original}/bin/ghc "$out/bin/ghc" \
+            --set LD_LIBRARY_PATH ${pkgs.lib.strings.makeLibraryPath dynamicLibraries} \
+            --set DYLD_LIBRARY_PATH ${pkgs.lib.strings.makeLibraryPath dynamicLibraries}
+        '';
+      };
+
+  hls =
+    let original = pkgs.haskell.packages.${pkgs.ghcName}.haskell-language-server;
+    in pkgs.stdenv.mkDerivation
+      {
+        name = original.name;
+        src = empty;
+        buildInputs = [ original pkgs.makeWrapper ];
+        installPhase = ''
+          mkdir -p "$out/bin"
+          makeWrapper ${original}/bin/haskell-language-server "$out/bin/haskell-language-server" \
+            --set LD_LIBRARY_PATH ${pkgs.lib.strings.makeLibraryPath dynamicLibraries} \
+            --set DYLD_LIBRARY_PATH ${pkgs.lib.strings.makeLibraryPath dynamicLibraries}
+          makeWrapper ${original}/bin/haskell-language-server-wrapper "$out/bin/haskell-language-server-wrapper" \
+            --set LD_LIBRARY_PATH ${pkgs.lib.strings.makeLibraryPath dynamicLibraries} \
+            --set DYLD_LIBRARY_PATH ${pkgs.lib.strings.makeLibraryPath dynamicLibraries}
+        '';
+      };
+
   baseInputs = [
     pkgs.stdenv
     pkgs.jq
@@ -56,15 +97,14 @@ let
   haskellInputs = [
     pkgs.cabal2nix
 
-    # The correct version of GHC.
-    pkgs.haskell.compiler.${pkgs.ghcName}
+    ghc
+    hls
 
     pkgs.haskell.packages.${pkgs.ghcName}.alex
     pkgs.haskell.packages.${pkgs.ghcName}.apply-refact
     (versions.ensureVersion pkgs.haskell.packages.${pkgs.ghcName}.cabal-install)
     pkgs.haskell.packages.${pkgs.ghcName}.ghcid
     pkgs.haskell.packages.${pkgs.ghcName}.happy
-    pkgs.haskell.packages.${pkgs.ghcName}.haskell-language-server
     (versions.ensureVersion pkgs.haskell.packages.${pkgs.ghcName}.hlint)
     pkgs.haskell.packages.${pkgs.ghcName}.hoogle
     pkgs.haskell.packages.${pkgs.ghcName}.hspec-discover