nix/haskell-packages: replace IFD with importing generated files

Building.md

@@ -78,3 +78,23 @@ https://github.com/ocaml/dune/issues/57 to see when a coverage report is viable
    _pass_ it the path to the binary.)
 
 
+## Updating Haskell Packages
+
+When the `.cabal` file of a Haskell package is changed you need to make sure the
+corresponding `default.nix` file (stored in the same directory as the `.cabal`
+file) is kept in sync with it.
+
+As mentioned in the `default.nix` files, these files are automatically generated:
+
+```
+# THIS IS AN AUTOMATICALLY GENERATED FILE. DO NOT EDIT MANUALLY!
+# To regenerate this file execute the following command in this directory:
+#
+# cp $(nix-build ./generate.nix --no-link)/default.nix ./default.nix
+```
+
+Note that they also contain the instructions on how to update them.
+
+Don't worry if you forget to update the `default.nix` file. There are CI jobs
+(like [`haskellSrc2nix.lsp-int`](https://hydra.dfinity.systems/job/dfinity-ci-build/motoko/haskellSrc2nix.lsp-int)
+that check if the files are in sync and fail with a diff if they aren't.

default.nix

@@ -411,6 +411,25 @@ rec {
   };
   stdlib-adocs = stdlib-doc.adocs;
 
+  haskellSrc2nix =
+    let
+      check = dir: nixpkgs.runCommandNoCC "check-${builtins.baseNameOf dir}" {
+        preferLocalBuild = true;
+        allowSubstitutes = false;
+        nativeBuildInputs = [ nixpkgs.diffutils ];
+        expected = import (dir + "/generate.nix") { pkgs = nixpkgs; };
+        inherit dir;
+      } ''
+        diff -U 3 $expected/default.nix $dir/default.nix
+        touch $out
+      '';
+    in {
+      lsp-int = check ./test/lsp-int;
+      qc-motoko = check ./test/random;
+      ic-stub = check ./ic-stub;
+      winter = check ./winter;
+    };
+
   all-systems-go = nixpkgs.releaseTools.aggregate {
     name = "all-systems-go";
     constituents = [

ic-stub/default.nix

@@ -0,0 +1,24 @@
+# THIS IS AN AUTOMATICALLY GENERATED FILE. DO NOT EDIT MANUALLY!
+# To regenerate this file execute the following command in this directory:
+#
+# cp $(nix-build ./generate.nix --no-link)/default.nix ./default.nix
+{ mkDerivation, base, binary, bytestring, containers
+, data-default-class, filepath, hex-text, mtl, optparse-applicative
+, primitive, stdenv, text, transformers, utf8-string, vector
+, winter
+}:
+mkDerivation {
+  pname = "ic-stub";
+  version = "0.1.0.0";
+  src = ./.;
+  isLibrary = false;
+  isExecutable = true;
+  executableHaskellDepends = [
+    base binary bytestring containers data-default-class filepath
+    hex-text mtl optparse-applicative primitive text transformers
+    utf8-string vector winter
+  ];
+  doCheck = false;
+  license = "unknown";
+  hydraPlatforms = stdenv.lib.platforms.none;
+}

ic-stub/generate.nix

@@ -0,0 +1 @@
+{ pkgs ? import ../nix {} }: pkgs.localHaskellSrc2nixWithDoc "ic-stub" ./. "--no-check"

nix/default.nix

@@ -25,6 +25,46 @@ let
             };
           }
         )
+        (self: super: {
+          # A variant of `haskellSrc2nixWithDoc` for local Haskell packages.
+          localHaskellSrc2nixWithDoc = name: path: extraCabal2nixOptions:
+            self.haskellSrc2nixWithDoc {
+              inherit name extraCabal2nixOptions;
+              src = import ./gitSource.nix path;
+              src_subst = "./.";
+            };
+
+          # `haskellSrc2nixWithDoc` is used to generate `default.nix` files for
+          # Haskell packages which are intended to be stored in the repository.
+          #
+          # The function generates a directory containing a `default.nix` which
+          # is the result of running `cabal2nix` with the `extraCabal2nixOptions`
+          # on the provided `src`.
+          #
+          # A header is added to `default.nix` which contains instructions on
+          # how to regenerate that file.
+          #
+          # Finally the `src` attribute in the `default.nix` will be defined as
+          # `src_subst` such that it can be pointed to local or niv-managed
+          # sources.
+          haskellSrc2nixWithDoc = {name, src, src_subst, extraCabal2nixOptions}:
+            let
+              drv = pkgs.haskellPackages.haskellSrc2nix {
+                inherit name extraCabal2nixOptions src;
+              };
+            in drv.overrideAttrs (oldAttrs: {
+              message = ''
+                # THIS IS AN AUTOMATICALLY GENERATED FILE. DO NOT EDIT MANUALLY!\
+                # To regenerate this file execute the following command in this directory:\
+                #\
+                # cp $(nix-build ./generate.nix --no-link)/default.nix ./default.nix
+              '';
+              inherit src_subst;
+              installPhase = oldAttrs.installPhase + ''
+                sed -i "1i$message;s|src = .*|src = $src_subst;|" $out/default.nix
+              '';
+            });
+        })
       ];
     };
 in

nix/haskell-packages.nix

@@ -9,11 +9,11 @@ nix: subpath:
 
   lsp-test = nix.haskell.lib.dontCheck self.lsp-test_0_10_1_0;
 
-  lsp-int = self.callCabal2nix "lsp-int" (subpath "test/lsp-int") { };
+  lsp-int = super.callPackage ../test/lsp-int {};
 
-  qc-motoko = self.callCabal2nix "qc-motoko" (subpath "test/random") { };
+  qc-motoko = super.callPackage ../test/random {};
 
-  winter = self.callCabal2nixWithOptions "winter" nix.sources.winter "--no-check" {};
+  winter = super.callPackage ../winter {};
 
-  ic-stub = self.callCabal2nixWithOptions "ic-stub" (subpath "ic-stub") "-frelease" { };
+  ic-stub = super.callPackage ../ic-stub {};
 }

test/lsp-int/default.nix

@@ -0,0 +1,21 @@
+# THIS IS AN AUTOMATICALLY GENERATED FILE. DO NOT EDIT MANUALLY!
+# To regenerate this file execute the following command in this directory:
+#
+# cp $(nix-build ./generate.nix --no-link)/default.nix ./default.nix
+{ mkDerivation, base, data-default, directory, filepath
+, haskell-lsp-types, hspec, HUnit, lens, lsp-test, stdenv, text
+}:
+mkDerivation {
+  pname = "lsp-int";
+  version = "0";
+  src = ./.;
+  isLibrary = false;
+  isExecutable = true;
+  executableHaskellDepends = [
+    base data-default directory filepath haskell-lsp-types hspec HUnit
+    lens lsp-test text
+  ];
+  description = "Integration tests for the language server";
+  license = "unknown";
+  hydraPlatforms = stdenv.lib.platforms.none;
+}

test/lsp-int/generate.nix

@@ -0,0 +1 @@
+{ pkgs ? import ../../nix {} }: pkgs.localHaskellSrc2nixWithDoc "lsp-int" ./. ""

test/random/default.nix

@@ -0,0 +1,22 @@
+# THIS IS AN AUTOMATICALLY GENERATED FILE. DO NOT EDIT MANUALLY!
+# To regenerate this file execute the following command in this directory:
+#
+# cp $(nix-build ./generate.nix --no-link)/default.nix ./default.nix
+{ mkDerivation, base, exceptions, managed, process, QuickCheck
+, quickcheck-text, quickcheck-unicode, stdenv, tasty
+, tasty-quickcheck, text, turtle
+}:
+mkDerivation {
+  pname = "qc-motoko";
+  version = "1";
+  src = ./.;
+  isLibrary = false;
+  isExecutable = true;
+  executableHaskellDepends = [
+    base exceptions managed process QuickCheck quickcheck-text
+    quickcheck-unicode tasty tasty-quickcheck text turtle
+  ];
+  description = "generate randomised tests for Motoko";
+  license = "unknown";
+  hydraPlatforms = stdenv.lib.platforms.none;
+}

test/random/generate.nix

@@ -0,0 +1 @@
+{ pkgs ? import ../../nix {} }: pkgs.localHaskellSrc2nixWithDoc "qc-motoko" ./. ""

winter/default.nix

@@ -0,0 +1,38 @@
+# THIS IS AN AUTOMATICALLY GENERATED FILE. DO NOT EDIT MANUALLY!
+# To regenerate this file execute the following command in this directory:
+#
+# cp $(nix-build ./generate.nix --no-link)/default.nix ./default.nix
+{ mkDerivation, pkgs, array, base, binary, byte-order, bytestring
+, cmdargs, containers, data-default-class, data-fix, deepseq
+, directory, filepath, FloatingHex, lifted-base, microlens-platform
+, monad-control, mtl, nats, parsec, primitive, primitive-unaligned
+, process, stdenv, tasty, tasty-hunit, tasty-quickcheck, temporary
+, text, transformers, vector
+}:
+mkDerivation {
+  pname = "winter";
+  version = "1.0.0";
+  src = pkgs.sources.winter;
+  isLibrary = true;
+  isExecutable = true;
+  libraryHaskellDepends = [
+    array base binary byte-order bytestring containers
+    data-default-class data-fix deepseq FloatingHex lifted-base
+    microlens-platform monad-control mtl nats parsec primitive
+    primitive-unaligned text transformers vector
+  ];
+  executableHaskellDepends = [
+    base binary bytestring cmdargs containers data-default-class mtl
+    parsec text
+  ];
+  testHaskellDepends = [
+    array base binary bytestring containers data-default-class data-fix
+    deepseq directory filepath FloatingHex lifted-base
+    microlens-platform monad-control mtl parsec primitive process tasty
+    tasty-hunit tasty-quickcheck temporary text transformers vector
+  ];
+  doCheck = false;
+  homepage = "https://github.com/dfinity/winter";
+  description = "Haskell port of the WebAssembly OCaml reference interpreter";
+  license = stdenv.lib.licenses.mit;
+}

winter/generate.nix

@@ -0,0 +1,15 @@
+{ pkgs ? import ../nix {} }:
+let
+  drv = pkgs.haskellSrc2nixWithDoc {
+    name = "winter";
+    src = pkgs.sources.winter;
+    src_subst = "pkgs.sources.winter";
+    extraCabal2nixOptions = "--no-check";
+  };
+in
+drv.overrideAttrs (oldAttrs: {
+  installPhase = oldAttrs.installPhase + ''
+    # Accept `pkgs` as an argument because the `src` depends on it.
+    sed -i "s|{ mkDerivation|{ mkDerivation, pkgs|" $out/default.nix
+  '';
+})