swiftpm2nix: init

pkgs/development/tools/swiftpm2nix/default.nix

@@ -0,0 +1,23 @@
+{ lib, stdenv, makeWrapper, jq, nix-prefetch-git }:
+
+stdenv.mkDerivation {
+  name = "swiftpm2nix";
+
+  nativeBuildInputs = [ makeWrapper ];
+
+  dontUnpack = true;
+
+  installPhase = ''
+    install -vD ${./swiftpm2nix.sh} $out/bin/swiftpm2nix
+    wrapProgram $out/bin/$name \
+      --prefix PATH : ${lib.makeBinPath [ jq nix-prefetch-git ]} \
+  '';
+
+  preferLocalBuild = true;
+
+  meta = {
+    description = "Generate a Nix expression to fetch swiftpm dependencies";
+    maintainers = with lib.maintainers; [ dtzWill trepetti dduan trundle stephank ];
+    platforms = lib.platforms.all;
+  };
+}

pkgs/development/tools/swiftpm2nix/swiftpm2nix.sh

@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+
+# Generates a Nix expression to fetch swiftpm dependencies, and a
+# configurePhase snippet to prepare a working directory for swift-build.
+
+set -eu -o pipefail
+shopt -s lastpipe
+
+pinFile="Package.resolved"
+stateFile=".build/workspace-state.json"
+
+for file in $pinFile $stateFile; do
+  if [[ ! -f "$file" ]]; then
+    echo >&2 "Missing $file. Run 'swift package resolve' first."
+    exit 1
+  fi
+done
+
+if [[ "$(jq .version $pinFile)" != "1" ]]; then
+  echo >&2 "Unsupported $pinFile version"
+  exit 1
+fi
+if [[ "$(jq .version $stateFile)" != "5" ]]; then
+  echo >&2 "Unsupported $stateFile version"
+  exit 1
+fi
+
+# Iterate dependencies and prefetch.
+sources=""
+jq -r '.object.dependencies[] | "\(.subpath) \(.packageRef.location) \(.state.checkoutState.revision)"' $stateFile \
+| while read -r name url rev; do
+  echo >&2 "-- Fetching $name"
+  sha256="$(nix-prefetch-git $url $rev | jq -r .sha256)"
+  sources+="
+    \"$name\" = fetchgit {
+      url = \"$url\";
+      rev = \"$rev\";
+      sha256 = \"$sha256\";
+    };"
+  echo >&2
+done
+sources+=$'\n'"  "
+
+# Generate output.
+mkdir -p nix
+# Copy the pin file as-is.
+cp $pinFile nix/Package.resolved
+# Copy the workspace state, but clear 'artifacts'.
+jq '.object.artifacts = []' < $stateFile > nix/workspace-state.json
+# Build an expression for fetching sources, and preparing the working directory.
+cat > nix/default.nix << EOF
+# This file was generated by swiftpm2nix.
+{ lib, fetchgit }: rec {
+  sources = {$sources};
+  configure = ''
+    mkdir -p .build/checkouts
+    ln -sf \${./Package.resolved} ./Package.resolved
+    install -m 0600 \${./workspace-state.json} ./.build/workspace-state.json
+  ''
+    + lib.concatStrings (lib.mapAttrsToList (name: src: ''
+      ln -s '\${src}' '.build/checkouts/\${name}'
+    '') sources)
+    + ''
+      # Helper that makes a swiftpm dependency mutable by copying the source.
+      swiftpmMakeMutable() {
+        local orig="\$(readlink .build/checkouts/\$1)"
+        rm .build/checkouts/\$1
+        cp -r "\$orig" .build/checkouts/\$1
+        chmod -R u+w .build/checkouts/\$1
+      }
+    '';
+}
+EOF
+echo >&2 "-- Generated ./nix"

pkgs/top-level/all-packages.nix

@@ -15044,6 +15044,8 @@ with pkgs;
   swiftPackages = recurseIntoAttrs (callPackage ../development/compilers/swift { });
   inherit (swiftPackages) swift;
 
+  swiftpm2nix = callPackage ../development/tools/swiftpm2nix { };
+
   swiProlog = callPackage ../development/compilers/swi-prolog {
     openssl = openssl_1_1;
     inherit (darwin.apple_sdk.frameworks) Security;