From d3f8dd15f3eb1e81eb0bdfeaed5b26550eca22f2 Mon Sep 17 00:00:00 2001
From: Vincent Ambo <tazjin@google.com>
Date: Fri, 23 Aug 2019 15:28:23 +0100
Subject: [PATCH] fix(gemma): Almost fix Gemma build by porting an old Elm

This pulls in an old version of Elm from NixOS 17.09 which can still
build the Elm code in Gemma.

However, the Common Lisp build is now broken in some other way.
---
 default.nix                | 11 ++++++++++-
 services/gemma/default.nix | 12 +++++-------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/default.nix b/default.nix
index 5d9f12820..8eb269506 100644
--- a/default.nix
+++ b/default.nix
@@ -12,7 +12,7 @@ let
     tazjin = {
       blog = import ./services/tazblog { inherit pkgs; };
       blog_cli = pkgs.callPackage ./tools/blog_cli {};
-      gemma = import ./services/gemma { inherit pkgs; };
+      gemma = pkgs.callPackage ./services/gemma {};
     };
 
     # Third-party projects (either vendored or modified from nixpkgs) go here:
@@ -25,6 +25,15 @@ let
       rev = "a7076c0f83e5c06ea9067b71171859fa2ba8afd9";
       sha256 = "1p4n2ja4ciw3qfskn65ggpy37mvgf2sslxqmqn8s8jjarnqcyfny";
     }) { pkgs = super; };
+
+    # Gemma needs an older version of Elm to be built. Updating it to
+    # the newer version is a lot of effort.
+    elmPackages = (import (super.fetchFromGitHub {
+      owner = "NixOS";
+      repo = "nixpkgs";
+      rev = "14f9ee66e63077539252f8b4550049381a082518";
+      sha256 = "1wn7nmb1cqfk2j91l3rwc6yhimfkzxprb8wknw5wi57yhq9m6lv1";
+    }) {}).elmPackages;
   };
 
   # The pinned commit here is identical to the public nixery.dev
diff --git a/services/gemma/default.nix b/services/gemma/default.nix
index 8c56e5668..537875b62 100644
--- a/services/gemma/default.nix
+++ b/services/gemma/default.nix
@@ -1,15 +1,9 @@
-with import <nixpkgs> {};
+{ stdenv, sbcl, lispPackages, elmPackages, pkgconfig }:
 
 stdenv.mkDerivation rec {
   name = "gemma";
-
   src = ./.;
 
-  # For the time being, Gemma can not be built because it requires an
-  # older version of Elm than what is available and Elm upgrade paths
-  # are painful.
-  broken = true;
-
   buildInputs = with lispPackages; [
     sbcl
     quicklisp
@@ -50,5 +44,9 @@ stdenv.mkDerivation rec {
     description = "Tool for tracking recurring tasks";
     homepage    = "https://github.com/tazjin/gemma";
     license     = licenses.gpl3;
+
+    # For the time being, Gemma can not be built because the Lisp build process
+    # broke in some way I haven't had time to debug.
+    broken = true;
   };
 }