ci: workaround for macOS GHA issue with wrapper fetching from spm plugin

Author: ktoso

Samples/SwiftJavaExtractJNISampleApp/build.gradle

@@ -209,3 +209,11 @@ jmh {
         "-Djextract.trace.downcalls=false"
     ]
 }
+
+task printGradleHome {
+    doLast {
+        println "Gradle Home: ${gradle.gradleHomeDir}"
+        println "Gradle Version: ${gradle.gradleVersion}"
+        println "Gradle User Home: ${gradle.gradleUserHomeDir}"
+    }
+}

Samples/SwiftJavaExtractJNISampleApp/ci-validate.sh

@@ -3,20 +3,37 @@
 set -x
 set -e
 
-# GitHub Actions workaround; We seem to be hitting gradle wrapper download issues, and this attempts to workaround them
-./gradlew -h
+if [[ "$(uname)" == "Darwin" && -n "$GITHUB_ACTION" ]]; then
+  # WORKAROUND: GitHub Actions on macOS issue with downloading gradle wrapper
+  # We seem to be hitting a problem when the swiftpm plugin, needs to execute gradle wrapper in a new gradle_user_home.
+  # Normally, this would just download gradle again and kick off a build, this seems to timeout *specifically* on
+  # github actions runners. 
+  # 
+  # It is not a sandbox problem, becuase the ./gradlew is run without sandboxing as we already execute 
+  # the entire swift build with '--disable-sandbox' for other reasons. 
+  #
+  # We cannot use the same gradle user home as the default one since we might make gradle think we're 
+  # building the same project concurrently, which we kind of are, however only a limited subset in order 
+  # to trigger wrap-java with those dependencies.
+  #
+  # TODO: this may use some further improvements so normal usage does not incur another wrapper download.
 
-GRADLE_USER_HOME="$(pwd)/.build/plugins/outputs/swiftjavaextractjnisampleapp/MySwiftLibrary/destination/JExtractSwiftPlugin/gradle-user-home"
-if [ -d "$HOME/.gradle" ] ; then
-  echo "COPY $HOME/.gradle to $GRADLE_USER_HOME"
-  mkdir -p "$GRADLE_USER_HOME"
-  cp -r "$HOME/.gradle/*" "$GRADLE_USER_HOME/" || true
-fi
+  ./gradlew -h # prime ~/.gradle/wrapper/dists/...
 
-# Verify the custom gradle home directory works  # TODO: remove this once verified
-./gradlew :SwiftKitCore:build --gradle-user-home $GRADLE_USER_HOME -p "$(pwd)/../../" --configure-on-demand --no-daemon
+  # Worst part of workaround here; we make sure to pre-load the resolved gradle wrapper downloaded distribution
+  # to the "known" location the plugin will use for its local builds, which are done in order to compile SwiftKitCore.
+  # This build is only necessary in order to drive wrap-java on sources generated during the build itself 
+  # which enables the "Implement Swift protocols in Java" feature of jextract/jni mode.
+  GRADLE_USER_HOME="$(pwd)/.build/plugins/outputs/swiftjavaextractjnisampleapp/MySwiftLibrary/destination/JExtractSwiftPlugin/gradle-user-home"
+  if [ -d "$HOME/.gradle" ] ; then
+    echo "COPY $HOME/.gradle to $GRADLE_USER_HOME"
+    mkdir -p "$GRADLE_USER_HOME"
+    cp -r "$HOME/.gradle/"* "$GRADLE_USER_HOME/" || true
+  fi
+fi
 
-swift build --disable-experimental-prebuilts --disable-sandbox --verbose  # FIXME: until prebuilt swift-syntax isn't broken on 6.2 anymore: https://github.com/swiftlang/swift-java/issues/418
+# FIXME: disable prebuilts until prebuilt swift-syntax isn't broken on 6.2 anymore: https://github.com/swiftlang/swift-java/issues/418
+swift build --disable-experimental-prebuilts --disable-sandbox  
 
 ./gradlew run
 ./gradlew test

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift

@@ -318,7 +318,7 @@ extension JNISwift2JavaGenerator {
           #".init(name: "\#(name)", signature: "\#(signature.mangledName)")"#
       }.joined(separator: ",\n")
 
-      return #"_JNIMethodIDCache(environment: try! JavaVirtualMachine.shared().environment(), className: "\#(fullClassName)", methods: [\#(methods)])"#
+      return #"_JNIMethodIDCache(className: "\#(fullClassName)", methods: [\#(methods)])"#
   }
 
   private func printEnumGetAsCaseThunk(