fix remote dependencies being inaccessible at runtime

Author: Grabsky

src/main/kotlin/dev/echonine/kite/Kite.kt

@@ -48,7 +48,7 @@ class Kite : JavaPlugin(), Listener {
             }
         }
         // Bump this if cache is no longer compatible between releases.
-        const val CACHE_VERSION = "3"
+        const val CACHE_VERSION = "4"
     }
 
     override fun onEnable() {

src/main/kotlin/dev/echonine/kite/scripting/ScriptManager.kt

@@ -16,6 +16,7 @@ import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlinx.coroutines.withContext
 import net.kyori.adventure.text.logger.slf4j.ComponentLogger
 import org.jetbrains.annotations.Unmodifiable
+import java.net.URLClassLoader
 import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.coroutines.resume
 import kotlin.script.experimental.api.ResultWithDiagnostics
@@ -123,10 +124,16 @@ internal class ScriptManager(val plugin: Kite) {
                 }
             }
         }
+        // Building a classloader that includes any JARs downloaded into the per-script libs directory.
+        val dependencies = Kite.Structure.CACHE_DIR.resolve(script.name).resolve("libs").walkTopDown()
+            .filter { it.isFile && it.extension == "jar" }
+            .map { it.toURI().toURL() }
+            .toList()
+        val classLoader = if (dependencies.isEmpty() == false) URLClassLoader(dependencies.toTypedArray(), Kite::class.java.classLoader) else Kite::class.java.classLoader
         // Creating EvaluationConfiguration based on KiteEvaluationConfiguration template.
         val evaluationConfiguration = KiteEvaluationConfiguration.with {
             jvm {
-                baseClassLoader(Kite::class.java.classLoader)
+                baseClassLoader(classLoader)
             }
             implicitReceivers(script)
             providedProperties(mapOf(

src/main/kotlin/dev/echonine/kite/scripting/configuration/KiteCompilationConfiguration.kt

@@ -91,9 +91,12 @@ object KiteCompilationConfiguration : ScriptCompilationConfiguration({
                 ?: return@onAnnotations context.compilationConfiguration.asSuccess()
             val scriptBaseDir = (context.script as? FileBasedScriptSource)?.file?.parentFile
             val importedSources: MutableList<FileScriptSource> = mutableListOf()
-            // We don't want to share the instance of KiteLibraryManager between compiler runs.
-            // Reason: It can easily stock up on stale repositories and dependencies.
-            val libraryManager = KiteLibraryManager()
+            val libsDirectory = Kite.Structure.CACHE_DIR.resolve("${context.compilationConfiguration[displayName]}").resolve("libs")
+            // Creating KiteLibraryManager instance. Downloads are placed in scripts' own 'plugins/Kite/cache/{SCRIPT}/libs/' directory because:
+            //   (1) this improves script isolation
+            //   (2) this does not require any extra tracking to know which dependencies should be added to runtime classpath
+            // We also don't want to share the instance of KiteLibraryManager between compiler runs. It can easily stock up on stale repositories and dependencies.
+            val libraryManager = KiteLibraryManager(libsDirectory)
             // Adding all declared repositories to the KiteLibraryManager instance.
             annotations.filterIsInstance<Repository>().map { it.repository }.forEach(libraryManager::addRepository)
             // Getting declared @Dependency and @Relocation annotations.

src/main/kotlin/dev/echonine/kite/scripting/libraries/KiteLibraryManager.kt

@@ -34,7 +34,7 @@ private class SoftLogAdapter(logger: Logger) : JDKLogAdapter(logger) {
 
 // This class is based on BukkitLibraryLoader and exists solely to track resolved dependencies.
 // Neither LibraryLoader#downloadLibrary nor LibraryLoader#loadLibrary do not return a comprehensive list of resolved dependencies.
-class KiteLibraryManager : LibraryManager(SoftLogAdapter(Kite.INSTANCE!!.logger), Kite.Structure.KITE_DIR.toPath(), Kite.Structure.LIBS_DIR.name) {
+class KiteLibraryManager(libsDirectory: File) : LibraryManager(SoftLogAdapter(Kite.INSTANCE!!.logger), libsDirectory.parentFile.toPath(), libsDirectory.name) {
     val resolvedPaths = ConcurrentHashMap.newKeySet<File>()!!
 
     // See that super method is not called here.