Add Nix support for more reproductive build

[SnO2WMaN]

Description

Added some Nix files for more reproducible (or more no (global) environment configuration) builds. Primary goal is making it easier to handle png supported upstream SATySFi with Nix.

I forgot to check before working this, a similar attempt was made several month ago. #322

Current Status

I tested on Linux (x86_64-linux) but may be able to in x86_64-darwin. You need to enable Nix Flake.

• nix build ".#satysfi" for build satysfi executable binary and lib-satysfi with fonts.
• nix build ".#doc-demo" for build ./demo/demo.saty
• nix build ".#doc-lang" for build ./doc/doc-lang.saty
• nix build ".#doc-primitives" for build ./doc/doc-primitives.saty
• nix run ".#satysfi" -- ./tests/images/test.saty or else to build document with latest version satysfi.

All results to ./result

[SnO2WMaN]

Currently can build by nix build ".#satysfi'" (Note that satysfi')

Copy src from https://github.com/NixOS/nixpkgs/blob/762b003329510ea855b4097a37511eb19c7077f0/pkgs/tools/typesetting/satysfi/default.nix

However, it is completely dependent on the version of nixpkgs.ocamlPackage, in other words, it does not consider satysfi.opam at all.

I found that tweag/opam-nix may have some problems.

[SnO2WMaN]

Currently can't build document with png images ( supported in #329 ) and I don't know why

Happens error
https://github.com/SnO2WMaN/SATySFi/blob/1bc985722d86c9fe5d2a52145fdc221b4d225581/src/frontend/main.ml#L623-L628

Occurence (maybe)
https://github.com/SnO2WMaN/SATySFi/blob/1bc985722d86c9fe5d2a52145fdc221b4d225581/src/backend/loadRawImage.ml#L11-L14

camlimage not successfully resolved as a dependency?

[gfngfn]

Currently can't build document with png images ( supported in #329 ) and I don't know why

Happens error
https://github.com/SnO2WMaN/SATySFi/blob/1bc985722d86c9fe5d2a52145fdc221b4d225581/src/frontend/main.ml#L623-L628

Occurence (maybe)
https://github.com/SnO2WMaN/SATySFi/blob/1bc985722d86c9fe5d2a52145fdc221b4d225581/src/backend/loadRawImage.ml#L11-L14

Could you show us the displayed error message?

camlimage not successfully resolved as a dependency?

I think that that is unlikely. Succeeding in building SATySFi implies having succeeded in resolving dependency.

[leque]

I tried this branch and got an error like below:

$ nix run ".#satysfi" -- ./tests/images/test.saty
...
 ---- ---- ---- ----
  embedding fonts ...
! [Error] cannot load image file 'basn0g02.png';
      unsupported

This error seems to be raised by camlimages. I am afraid that camlimages is not built with png support. (It was not able to find libpng at configure time?)

[SnO2WMaN]

@leque
As you pointed out, I found that there is some problem between camlimages that Nix is (supposedly) building internally and libpng

Different output (more-detailed) when I switched to libpng12 (unpatched libpng 1.2.59)

 ---- ---- ---- ----
  embedding fonts ...
libpng warning: Invalid color type/bit depth combination in IHDR
libpng error: Invalid IHDR data
! [Error] cannot load image file 'basn0g02.png';
      png read error

[SnO2WMaN]

I have tested with overriding the official definition file for satysfi, and I found that the problem may be cause of either nixpkgs.ocamlPackages.camlimages or nixpkgs.libpng. Unfortunately, I'm not familiar with OCaml, so this pr will be postponed until some effective way of dealing with this problem.

[balsoft]

The aforementioned test passes if I run nix run . -- ./tests/images/test.saty with the following flake.nix and latest version of opam-nix (I have included some new overlays in there that fix camlimages and camlpdf here, so make sure to run nix flake lock --update-input opam-nix). I also took a liberty to fix your nix-filter invocation and remove some unneeded overlays.

{
  description = "Nix Flake for SATySFi";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    opam-nix.url = "github:tweag/opam-nix";
    satysfi-external-repo = {
      url = "github:gfngfn/satysfi-external-repo";
      flake = false;
    };

    # develop
    nix-filter.url =
      "github:numtide/nix-filter/3e1fff9ec0112fe5ec61ea7cc6d37c1720d865f8";
    devshell.url = "github:numtide/devshell";
    flake-utils.url = "github:numtide/flake-utils";
    flake-compat = {
      url = "github:edolstra/flake-compat";
      flake = false;
    };
  };
  outputs = { self, nixpkgs, nix-filter, opam-nix, satysfi-external-repo
    , devshell, flake-utils, ... }:
    flake-utils.lib.eachSystem [ "x86_64-linux" "x86_64-darwin" ] (system:
      let
        inherit (pkgs) lib stdenv;
        inherit (opam-nix.lib.${system}) buildDuneProject makeOpamRepoRec;
        pkgs = nixpkgs.legacyPackages.${system}.extend devshell.overlay;

        duneProject = buildDuneProject {
          repos = [
            opam-nix.inputs.opam-repository
            (makeOpamRepoRec satysfi-external-repo)
          ];
        } "satysfi" (with nix-filter.lib;
          filter {
            root = ./.;
            include = [
              "dune-project"
              "satysfi.opam"
              "Makefile"
              (inDirectory "bin")
              (inDirectory "obsolete")
              (inDirectory "src")
              (inDirectory "tools")
              (inDirectory "lib-satysfi")
            ];
            exclude = [ ".merlin" ];
          }) { satysfi = null; };
        duneProjectOverlay = self: super: {
          satysfi = super.satysfi.overrideAttrs (oa: {
            doNixSupport = false;
            removeOcamlReferences = true;
            preConfigure = ''
              substituteInPlace src/frontend/main.ml \
              --replace \
                '/usr/local/share/satysfi"; "/usr/share/satysfi' \
                $out/share/satysfi
            '';
            installPhase = with pkgs; ''
              cp -r ${lmodern}/share/fonts/opentype/public/lm/* lib-satysfi/dist/fonts/
              cp -r ${lmmath}/share/fonts/opentype/latinmodern-math.otf lib-satysfi/dist/fonts/
              cp -r ${ipaexfont}/share/fonts/opentype/* lib-satysfi/dist/fonts/
              cp -r ${junicode}/share/fonts/junicode-ttf/* lib-satysfi/dist/fonts/
              make install PREFIX=$out LIBDIR=$out/share/satysfi
              mkdir -p $out/share/satysfi/
              cp -r lib-satysfi/dist/ $out/share/satysfi/
            '';
          });
        };
        ocamlPkgs = duneProject.overrideScope' duneProjectOverlay;

        mkDoc = { name, root, entrypoint, output, }:
          stdenv.mkDerivation {
            name = "doc-${name}";
            buildInputs = with self.packages.${system}; [ satysfi ];
            src = with (nix-filter.lib);
              filter {
                root = root;
                exclude = [ (matchExt "pdf") (matchExt "satysfi-aux") ];
              };
            buildPhase = ''
              satysfi ${entrypoint} --output ${output}
            '';
            installPhase = ''
              mkdir -p $out
              cp ${output} $out
            '';
          };
      in {
        packages.default = self.packages.${system}.satysfi;
        packages.satysfi = ocamlPkgs.satysfi;

        packages.doc-demo = mkDoc {
          name = "demo";
          root = ./demo;
          entrypoint = "demo.saty";
          output = "demo.pdf";
        };
        packages.doc-lang = mkDoc {
          name = "lang";
          root = ./doc;
          entrypoint = "doc-lang.saty";
          output = "doc-lang.pdf";
        };
        packages.doc-primitives = mkDoc {
          name = "lang";
          root = ./doc;
          entrypoint = "doc-primitives.saty";
          output = "doc-primitives.pdf";
        };
        packages.tests-images = mkDoc {
          name = "tests-image";
          root = ./tests/images;
          entrypoint = "test.saty";
          output = "test.pdf";
        };

        apps.satysfi =
          flake-utils.lib.mkApp { drv = self.packages.${system}.satysfi; };

        apps.default = self.apps.${system}.satysfi;

        devShells.default = pkgs.devshell.mkShell {
          packages = with pkgs; [
            # develop
            treefmt # wrapper cli to run all formatters
            alejandra # Nix formatter
          ];
        };

        checks = {
          inherit (self.packages.${system})
            satysfi doc-demo doc-lang doc-primitives;
        };
      });
}

[SnO2WMaN]

@balsoft

I have tested that I can build documents with pngs here as well, thank you very much!. This PR is now undrafted.