gradle: auto-detect nativeVersion

Instead of having to know the version of native-platform at the Nix
level, we use the file `lib/native-platform-<version>.jar` to figure
out the version of the library JAR to patch.

pkgs/development/tools/build-managers/gradle/default.nix

···
 rec {
   gen =
 
-    { version, nativeVersion, hash,
+    { version, hash,
 
       # The default JDK/JRE that will be used for derived Gradle packages.
       # A current LTS version of a JDK is a good choice.
···
     , testers
     , runCommand
     , writeText
+    , autoPatchelfHook
 
     # The JDK/JRE used for running Gradle.
     , java ? defaultJava
···
 
       dontBuild = true;
 
-      nativeBuildInputs = [ makeWrapper unzip ];
-      buildInputs = [ java ];
+      nativeBuildInputs = [
+        makeWrapper
+        unzip
+      ] ++ lib.optionals stdenv.isLinux [
+        autoPatchelfHook
+      ];
+
+      buildInputs = [
+        java
+        stdenv.cc.cc
+        ncurses5
+        ncurses6
+      ];
+
+      # We only need to patchelf some libs embedded in JARs.
+      dontAutoPatchelf = true;
 
       installPhase = with builtins;
         let
···
 
       fixupPhase = let arch = if stdenv.is64bit then "amd64" else "i386";
       in ''
+        . ${./patching.sh}
+
+        nativeVersion="$(extractVersion native-platform $out/lib/gradle/lib/native-platform-*.jar)"
         for variant in "" "-ncurses5" "-ncurses6"; do
-          mkdir "patching$variant"
-          pushd "patching$variant"
-          jar xf $out/lib/gradle/lib/native-platform-linux-${arch}$variant-${nativeVersion}.jar
-          patchelf \
-            --set-rpath "${stdenv.cc.cc.lib}/lib64:${lib.makeLibraryPath [ stdenv.cc.cc ncurses5 ncurses6 ]}" \
-            net/rubygrapefruit/platform/linux-${arch}$variant/libnative-platform*.so
-          jar cf native-platform-linux-${arch}$variant-${nativeVersion}.jar .
-          mv native-platform-linux-${arch}$variant-${nativeVersion}.jar $out/lib/gradle/lib/
-          popd
+          autoPatchelfInJar \
+            $out/lib/gradle/lib/native-platform-linux-${arch}$variant-''${nativeVersion}.jar \
+            "${stdenv.cc.cc.lib}/lib64:${lib.makeLibraryPath [ stdenv.cc.cc ncurses5 ncurses6 ]}"
         done
 
         # The scanner doesn't pick up the runtime dependency in the jar.
···
 
   gradle_8 = gen {
     version = "8.10";
-    nativeVersion = "0.22-milestone-26";
     hash = "sha256-W5xes/n8LJSrrqV9kL14dHyhF927+WyFnTdBGBoSvyo=";
     defaultJava = jdk21;
   };
 
   gradle_7 = gen {
     version = "7.6.4";
-    nativeVersion = "0.22-milestone-25";
     hash = "sha256-vtHaM8yg9VerE2kcd/OLtnOIEZ5HlNET4FEDm4Cvm7E=";
     defaultJava = jdk17;
   };
 
   gradle_6 = gen {
     version = "6.9.4";
-    nativeVersion = "0.22-milestone-20";
     hash = "sha256-PiQCKFON6fGHcqV06ZoLqVnoPW7zUQFDgazZYxeBOJo=";
     defaultJava = jdk11;
   };

pkgs/development/tools/build-managers/gradle/patching.sh

···
+extractVersion() {
+    local jar version
+    local prefix="$1"
+    shift
+    local candidates="$@"
+
+    jar="$(basename -a $candidates | sort | head -n1)"
+
+    version="${jar#$prefix-}"
+
+    echo "${version%.jar}"
+}
+
+autoPatchelfInJar() {
+    local file="$1" rpath="$2"
+    local work
+
+    work="$(mktemp -dt patching.XXXXXXXXXX)"
+    pushd "$work"
+
+    jar xf "$file"
+    rm "$file"
+
+    autoPatchelf -- .
+
+    jar cf "$file" .
+
+    popd
+}

pkgs/development/tools/build-managers/gradle/update.sh

···
     read -d "\n" gradle_hash gradle_path < <(nix-prefetch-url --print-path $url)
     gradle_hash=$(nix-hash --to-sri --type sha256 "$gradle_hash")
 
-    # Prefix and suffix for "native-platform" dependency.
-    gradle_native_prefix="gradle-$v/lib/native-platform-"
-    gradle_native_suffix=".jar"
-    tmp=$(mktemp)
-    zipinfo -1 "$gradle_path" "$gradle_native_prefix*$gradle_native_suffix" > $tmp
-    gradle_native=$(cat $tmp | head -n1)
-    gradle_native=${gradle_native#"$gradle_native_prefix"}
-    gradle_native=${gradle_native%"$gradle_native_suffix"}
-
-    # Supported architectures
-    #grep -Pho "(linux|osx)-\w+" $tmp | sort | uniq
-    rm -f $tmp
-
-    echo -e "{\\n  version = \"$v\";\\n  nativeVersion = \"$gradle_native\";\\n  sha256 = \"$gradle_hash\";\\n}" > $f
+    echo -e "{\\n  version = \"$v\";\\n  sha256 = \"$gradle_hash\";\\n}" > $f
 
     echo "$v DONE"
 done