Allow filtered sources

Fixes #31

Author: raphiz

buildGradleApplication/mkM2Repository.nix

@@ -11,16 +11,29 @@
   repositories ? ["https://plugins.gradle.org/m2/" "https://repo1.maven.org/maven2/"],
   verificationFile ? "gradle/verification-metadata.xml",
 }: let
-  filteredSrc = lib.fileset.toSource {
-    root = src;
-    fileset = lib.path.append src verificationFile;
-  };
+  verificationXmlFile =
+    if lib.isPath src
+    then lib.path.append src verificationFile
+    else let
+      storePathPrefix = "${src}/";
+    in
+      lib.cleanSourceWith {
+        src = storePathPrefix;
+        filter = path: type: let
+          relPath = lib.removePrefix storePathPrefix path;
+        in
+          if type == "directory"
+          then lib.strings.hasPrefix relPath verificationFile
+          else relPath == verificationFile;
+      }
+      + "/"
+      + verificationFile;
 
   depSpecs = builtins.filter dependencyFilter (
     # Read all build and runtime dependencies from the verification-metadata XML
     builtins.fromJSON (builtins.readFile (
       runCommand "depSpecs" {buildInputs = [python3];}
-      "python ${./parse.py} ${filteredSrc}/${verificationFile} ${builtins.toString (builtins.map lib.escapeShellArg repositories)}> $out"
+      "python ${./parse.py} ${verificationXmlFile} ${builtins.toString (builtins.map lib.escapeShellArg repositories)}> $out"
     ))
   );
   mkDep = depSpec: {
@@ -34,7 +47,7 @@
   # write a dedicated script for the m2 repository creation. Otherwise, the m2Repository derivation might crash with 'Argument list too long'
   m2Repository =
     runCommand "${pname}-${version}-m2-repository"
-    {src = filteredSrc;}
+    {}
     (
       "mkdir $out"
       + lib.concatMapStringsSep "\n" (dep: "mkdir -p $out/${dep.path}\nln -s ${builtins.toString dep.jar} $out/${dep.path}/${dep.name}") dependencies

examples/hello-world/package.nix

@@ -13,7 +13,18 @@ in
   buildGradleApplication {
     inherit gradle version jdk;
     pname = "hello-world";
-    src = ./.;
+    src = lib.cleanSourceWith {
+      src = lib.cleanSource ./.;
+      filter = path: type: let
+        ignore = builtins.elem (baseNameOf path);
+      in
+        ! ignore [
+          "package.nix"
+          "gradlew.bat"
+          "gradlew"
+        ];
+    };
+
     meta = with lib; {
       description = "Hello World Application";
       longDescription = ''