1 files changed, 59 insertions, 0 deletions
diff --git a/pkgs/development/tools/godot/3/mono/make-deps.nix b/pkgs/development/tools/godot/3/mono/make-deps.nix
new file mode 100644
index 0000000000000..e47a5a68d64ba
--- /dev/null
+++ b/pkgs/development/tools/godot/3/mono/make-deps.nix
@@ -0,0 +1,59 @@
+{ godot3-mono, nuget-to-nix }:
+
+godot3-mono.overrideAttrs (self: base: {
+  pname = "godot3-mono-make-deps";
+
+  nativeBuildInputs = base.nativeBuildInputs ++ [ nuget-to-nix ];
+
+  nugetDeps = null;
+  nugetSource = null;
+  nugetConfig = null;
+
+  shouldConfigureNuget = false;
+
+  outputs = [ "out" ];
+  buildPhase = " ";
+  installPhase = ''echo "No output intended. Run make-deps.sh instead." > $out'';
+
+  # This script is used to update the accompanying deps.nix file, a nix expression listing the
+  # nuget packages that the godot-mono code depends on, along with their sha256 hashes. This
+  # file is referenced by the godot-mono derivation and needs to be updated every time the
+  # godot version is updated. The way it works is:
+  #
+  # 1) Creates and navigates to a temporary directory and then explicitly runs the unpack,
+  # patch, and configure phases from the godot-mono derivation.
+  # 2) Instead of building at this point, a nuget restore is performed, downloading all the
+  # nuget dependencies of godot-mono into a local folder.
+  # 3) Once these have been downloaded, the nuget-to-nix tool is used to generate a nix
+  # expression listing the locally obtained nuget packages, along with their sha256 hashes.
+  # 4) This nix expression is saved as deps.nix in the PWD.
+  #
+  # This process is impure, because it entails downloading files with unknown hashes, so it
+  # is run manually by the maintainer within a nix-shell environment. Running the accompanying
+  # make-deps.sh instead simplifies this.
+  makeDeps = ''
+    set -e
+    outdir="$(pwd)"
+    wrkdir="$(mktemp -d)"
+    trap 'rm -rf -- "$wrkdir"' EXIT
+    pushd "$wrkdir" > /dev/null
+      unpackPhase
+      cd source
+      patchPhase
+      configurePhase
+
+      # Without RestorePackagesPath set, it restores packages to a temp directory. Specifying
+      # a path ensures we have a place to run nuget-to-nix.
+      nugetRestore() { dotnet msbuild -t:Restore -p:RestorePackagesPath=nugetPackages $1; }
+
+      nugetRestore modules/mono/glue/GodotSharp/GodotSharp.sln
+      nugetRestore modules/mono/editor/GodotTools/GodotTools.sln
+
+      nuget-to-nix nugetPackages > "$outdir"/deps.nix
+    popd > /dev/null
+  '';
+
+  meta = base.meta // {
+    description = "Derivation with no output that exists to provide an environment for make-deps.sh";
+  };
+})