Move Gradle build logic to a setup hook

nix/build-gradle-package.nix

@@ -0,0 +1,145 @@
+# This file is generated by gradle2nix.
+#
+# Example usage (e.g. in default.nix):
+#
+#     with (import <nixpkgs> {});
+#     let
+#       buildGradle = callPackage ./gradle.nix {};
+#     in
+#       buildGradle {
+#         lockFile = ./gradle.lock;
+#
+#         src = ./.;
+#
+#         gradleFlags = [ "installDist" ];
+#
+#         installPhase = ''
+#           mkdir -p $out
+#           cp -r app/build/install/myproject $out
+#         '';
+#       }
+
+{
+  lib,
+  stdenv,
+  gradle,
+  buildMavenRepo,
+  gradleSetupHook,
+  writeText,
+}:
+
+{
+  # Path to the lockfile generated by gradle2nix (e.g. gradle.lock).
+  lockFile ? null,
+  pname ? "project",
+  version ? null,
+  # The Gradle package to use. Default is 'pkgs.gradle'.
+  gradlePackage ? gradle,
+  # Override the default JDK used to run Gradle itself.
+  buildJdk ? null,
+  # Override functions which fetch dependency artifacts.
+  # Names in this set are URL schemes such as "https" or "s3".
+  # Values are functions which take a dependency in the form
+  # `{ urls, hash }` and fetch into the Nix store. For example:
+  #
+  #   {
+  #     s3 = { name, urls, hash }: fetchs3 {
+  #       s3url = builtins.head urls;
+  #       # TODO This doesn't work without patching fetchs3 to accept SRI hashes
+  #       inherit name hash;
+  #       region = "us-west-2";
+  #       credentials = {
+  #         access_key_id = "foo";
+  #         secret_access_key = "bar";
+  #       };
+  #     };
+  #   }
+  fetchers ? { },
+  # Override artifacts in the offline Maven repository.
+  #
+  # This is an attrset is of the form:
+  #
+  #   {
+  #     "${group}:${module}:${version}" = {
+  #       "${filename}" = <override function>;
+  #     }
+  #   }
+  #
+  # The override function takes the original derivation from 'fetchers' (e.g. the result of
+  # 'fetchurl') and produces a new derivation to replace it.
+  #
+  # Examples:
+  #
+  # 1. Replace a dependency's JAR artifact:
+  #
+  #    {
+  #      "com.squareup.okio:okio:3.9.0"."okio-3.9.0.jar" = _: fetchurl {
+  #        url = "https://repo.maven.apache.org/maven2/com/squareup/okio/okio/3.9.0/okio-3.9.0.jar";
+  #        hash = "...";
+  #        downloadToTemp = true;
+  #        postFetch = "install -Dt $out/com/squareup/okio/okio/3.9.0/ $downloadedFile"
+  #      };
+  #    }
+  #
+  # 2. Patch a JAR containing native binaries:
+  #
+  #    {
+  #      "com.android.tools.build:aapt2:8.5.0-rc02-11315950" = {
+  #        "aapt2-8.5.0-rc02-11315950-linux.jar" = src: runCommandCC src.name {
+  #          nativeBuildInputs = [ jdk autoPatchelfHook ];
+  #          dontAutoPatchelf = true;
+  #        } ''
+  #          cp ${src} aapt2.jar
+  #          jar xf aapt2.jar aapt2
+  #          chmod +x aapt2
+  #          autoPatchelf aapt2
+  #          jar uf aapt2.jar aapt2
+  #          cp aapt2.jar $out
+  #        '';
+  #      }
+  #    }
+  overrides ? { },
+  ...
+}@args:
+
+let
+  inherit (builtins) removeAttrs;
+
+  gradleSetupHook' = gradleSetupHook.overrideAttrs (_: {
+    propagatedBuildInputs = [ gradlePackage ];
+  });
+
+  offlineRepo =
+    if lockFile != null then buildMavenRepo { inherit lockFile fetchers overrides; } else null;
+
+  buildGradlePackage = stdenv.mkDerivation (
+    finalAttrs:
+    {
+
+      inherit buildJdk pname version;
+
+      inherit (offlineRepo) gradleInitScript;
+
+      dontStrip = true;
+
+      nativeBuildInputs = (args.nativeBuildInputs or [ ]) ++ [ gradleSetupHook' ];
+
+      gradleFlags =
+        [ "--console=plain" ]
+        ++ lib.optional (finalAttrs.buildJdk != null) "-Dorg.gradle.java.home=${finalAttrs.buildJdk.home}";
+
+      passthru =
+        lib.optionalAttrs (offlineRepo != null) { inherit offlineRepo; } // (args.passthru or { });
+    }
+    // removeAttrs args [
+      "gradle"
+      "gradleInitScript"
+      "lockFile"
+      "fetchers"
+      "nativeBuildInputs"
+      "overlays"
+      "passthru"
+    ]
+  );
+in
+buildGradlePackage