implementing overlays with haskellPackages

clean-source-haskell.nix

@@ -1,5 +1,6 @@
-src:
-  if (builtins.typeOf src) == "path"
+pkgs: src:
+  let lib = pkgs.lib;
+  in if (builtins.typeOf src) == "path"
     then lib.cleanSourceWith {
       filter = with pkgs.stdenv;
         name: type: let baseName = baseNameOf (toString name); in ! (

default.nix

@@ -0,0 +1,8 @@
+{
+  fetchNixpkgs = import ./fetch-nixpkgs.nix;
+  cleanSourceHaskell = import ./clean-source-haskell.nix;
+  haskellPackages = ./haskell-packages.nix;
+  maybeEnv = import ./maybe-env.nix;
+  jemallocOverlay = import ./overlays/jemalloc.nix;
+  getPackages = import ./get-packages.nix;
+}

fetch-nixpkgs.nix

@@ -1,5 +1,5 @@
-let
-  spec = builtins.fromJSON (builtins.readFile ../nixpkgs-src.json);
+srcJson: let
+  spec = builtins.fromJSON (builtins.readFile srcJson);
 in builtins.fetchTarball {
   url = "${spec.url}/archive/${spec.rev}.tar.gz";
   inherit (spec) sha256;

get-packages.nix

@@ -0,0 +1,5 @@
+haskellPackages: filter:
+  let
+    cusutmPackages = lib.filterAttrs (name: drv: filter name) haskellPackages;
+  in
+    customPackages

haskell-packages.nix

@@ -2,11 +2,14 @@
 , forceDontCheck
 , enableProfiling
 , enablePhaseMetrics
+, enableHaddockHydra
 , enableBenchmarks
+, enableSplitCheck
 , fasterBuild
 , enableDebugging
 , filter
 , requiredOverlay
+, pkgsGenerated
 }:
 
 with pkgs.lib;
@@ -16,23 +19,27 @@ let
   ghc = pkgs.haskell.compiler.ghc822;
 
   # This will yield a set of haskell packages, based on the given compiler.
-  kgsBase = ((import ../pkgs { inherit pkgs; }).override {
+  pkgsBase = ((import pkgsGenerated { inherit pkgs; }).override {
     inherit ghc;
   });
 
   # Overlay logic for *haskell* packages.
-  requiredOverlay    = import requiredOverlay             { inherit pkgs enableProfiling; };
-  benchmarkOverlay   = import ./overlays/benchmark.nix    { inherit pkgs filter; };
-  debugOverlay       = import ./overlays/debug.nix        { inherit pkgs; };
-  fasterBuildOverlay = import ./overlays/faster-build.nix { inherit pkgs filter; };
-  dontCheckOverlay   = import ./overlays/dont-check.nix   { inherit pkgs; };
-  metricOverlay      = import ./overlays/metric.nix       { inherit pkgs; };
+  requiredOverlay'    = import requiredOverlay              { inherit pkgs enableProfiling; };
+  benchmarkOverlay    = import ./overlays/benchmark.nix     { inherit pkgs filter; };
+  debugOverlay        = import ./overlays/debug.nix         { inherit pkgs; };
+  fasterBuildOverlay  = import ./overlays/faster-build.nix  { inherit pkgs filter; };
+  dontCheckOverlay    = import ./overlays/dont-check.nix    { inherit pkgs; };
+  metricOverlay       = import ./overlays/metric.nix        { inherit pkgs; };
+  haddockHydraOverlay = import ./overlays/haddock-hydra.nix { inherit pkgs filter; };
+  splitCheckOverlay   = import ./overlays/split-check.nix   { inherit pkgs filter; };
 
-  activeOverlays = [ requiredOverlay ]
+  activeOverlays = [ requiredOverlay' ]
       ++ optional enablePhaseMetrics metricOverlay
       ++ optional enableBenchmarks benchmarkOverlay
       ++ optional enableDebugging debugOverlay
       ++ optional forceDontCheck dontCheckOverlay
+      ++ optional forceDontCheck splitCheckOverlay
+      ++ optional forceDontCheck haddockHydraOverlay
       ++ optional fasterBuild fasterBuildOverlay;
 
 in

maybe-env.nix

@@ -0,0 +1,8 @@
+# Gets the value of an environment variable, with a default if it's
+# unset or empty.
+env: default:
+  let
+    result = builtins.getEnv env;
+  in if result != ""
+     then result
+     else default

overlays/benchmark.nix

@@ -1,6 +1,9 @@
-{ pkgs, filter }:
+let
+  isBenchmark = args: !((args.isExecutable or false) || (args.isLibrary or true));
 
-with import ../../lib.nix;
+in { pkgs, filter }:
+
+with pkgs.lib;
 
 self: super: {
   mkDerivation = args: super.mkDerivation (args // optionalAttrs (filter args.pname) {

overlays/faster-build.nix

@@ -3,7 +3,7 @@
 
 { pkgs, filter }:
 
-with import ../../lib.nix;
+with pkgs.lib;
 
 self: super: {
   mkDerivation = args: super.mkDerivation (args // optionalAttrs (filter args.pname) {

overlays/haddock-hydra.nix

@@ -0,0 +1,16 @@
+{ pkgs, filter }:
+
+with pkgs.lib;
+
+self: super: {
+    mkDerivation = args: super.mkDerivation (args // optionalAttrs (filter args.pname) {
+      doHaddock = true;
+      postInstall = ''
+        ${args.postInstall or ""}
+        mkdir -pv $doc/nix-support
+        tar -czvf $doc/${args.pname}-docs.tar.gz -C $doc/share/doc/html .
+        echo "file binary-dist $doc/${args.pname}-docs.tar.gz" >> $doc/nix-support/hydra-build-products
+        echo "report ${args.pname}-docs.html $doc/share/doc/html index.html" >> $doc/nix-support/hydra-build-products
+      '';
+    });
+  }

overlays/split-check.nix

@@ -0,0 +1,9 @@
+{ pkgs, filter }:
+
+with pkgs.lib;
+
+self: super: {
+    mkDerivation = args: super.mkDerivation (args // optionalAttrs (filter args.pname) {
+      splitCheck = true;
+    });
+  }

run-haskell.nix

@@ -0,0 +1,11 @@
+name: pkgs: hspkgs: deps: env: code: let
+    lib = pkgs.lib;
+    ghc = hspkgs.ghcWithPackages deps;
+    flags = lib.optionalString pkgs.stdenv.isDarwin "-liconv";  # https://github.com/NixOS/nixpkgs/issues/46814
+    builtBinary = pkgs.runCommand "${name}-binary" { buildInputs = [ ghc ]; } ''
+      mkdir -p $out/bin/
+      ghc ${pkgs.writeText "${name}.hs" code} ${flags} -o $out/bin/${name}
+    '';
+  in pkgs.runCommand name env ''
+    ${builtBinary}/bin/$name
+  ''