Implement and use helpers for economical classpath update in script configs

libraries/scripting/jvm-host/src/kotlin/script/experimental/jvmhost/impl/KJvmCompilerImpl.kt

@@ -51,6 +51,7 @@ import kotlin.script.experimental.jvm.JvmDependency
 import kotlin.script.experimental.jvm.impl.BridgeDependenciesResolver
 import kotlin.script.experimental.jvm.jdkHome
 import kotlin.script.experimental.jvm.jvm
+import kotlin.script.experimental.jvm.withUpdatedClasspath
 import kotlin.script.experimental.jvmhost.KJvmCompilerProxy
 import kotlin.script.experimental.util.getOrError
 
@@ -79,11 +80,8 @@ class KJvmCompilerImpl(val hostConfiguration: ScriptingHostConfiguration) : KJvm
 
             fun updateClasspath(classpath: List<File>) {
                 environment!!.updateClasspath(classpath.map(::JvmClasspathRoot))
-                if (classpath.isNotEmpty()) {
-                    updatedConfiguration = ScriptCompilationConfiguration(updatedConfiguration) {
-                        dependencies.append(JvmDependency(classpath))
-                    }
-                }
+
+                updatedConfiguration = updatedConfiguration.withUpdatedClasspath(classpath)
             }
 
             val disposable = Disposer.newDisposable()
@@ -122,9 +120,7 @@ class KJvmCompilerImpl(val hostConfiguration: ScriptingHostConfiguration) : KJvm
                         add(CLIConfigurationKeys.CONTENT_ROOTS, JvmClasspathRoot(file))
                     }
                 }
-                updatedConfiguration = ScriptCompilationConfiguration(updatedConfiguration) {
-                    dependencies.append(JvmDependency(standardLibs.map { it.second }))
-                }
+                updatedConfiguration = updatedConfiguration.withUpdatedClasspath(standardLibs.map { it.second })
 
                 put(CommonConfigurationKeys.MODULE_NAME, "kotlin-script") // TODO" take meaningful and valid name from somewhere
                 languageVersionSettings = LanguageVersionSettingsImpl(

libraries/scripting/jvm/src/kotlin/script/experimental/jvm/jvmScriptCompilation.kt

@@ -38,11 +38,42 @@ fun JvmScriptCompilationConfigurationBuilder.dependenciesFromClassloader(
     classLoader: ClassLoader = Thread.currentThread().contextClassLoader,
     wholeClasspath: Boolean = false
 ) {
-    ScriptCompilationConfiguration.dependencies.append(
-        JvmDependency(scriptCompilationClasspathFromContext(*libraries, classLoader = classLoader, wholeClasspath = wholeClasspath))
+    updateClasspath(
+        scriptCompilationClasspathFromContext(*libraries, classLoader = classLoader, wholeClasspath = wholeClasspath)
     )
 }
 
+fun ScriptCompilationConfiguration.withUpdatedClasspath(classpath: Collection<File>): ScriptCompilationConfiguration {
+
+    val newClasspath = classpath.filterNewClasspath(this[ScriptCompilationConfiguration.dependencies])
+        ?: return this
+
+    return ScriptCompilationConfiguration(this) {
+        dependencies.append(JvmDependency(newClasspath))
+    }
+}
+
+fun ScriptCompilationConfiguration.Builder.updateClasspath(classpath: Collection<File>) = updateClasspathImpl(classpath)
+
+fun JvmScriptCompilationConfigurationBuilder.updateClasspath(classpath: Collection<File>) = updateClasspathImpl(classpath)
+
+private fun PropertiesCollection.Builder.updateClasspathImpl(classpath: Collection<File>) {
+    val newClasspath = classpath.filterNewClasspath(this[ScriptCompilationConfiguration.dependencies])
+        ?: return
+
+    ScriptCompilationConfiguration.dependencies.append(JvmDependency(newClasspath))
+}
+
+private fun Collection<File>.filterNewClasspath(known: Collection<ScriptDependency>?): List<File>? {
+
+    if (isEmpty()) return null
+
+    val knownClasspath = known?.flatMapTo(hashSetOf<File>()) {
+        (it as? JvmDependency)?.classpath ?: emptyList()
+    }
+    return filterNot { knownClasspath?.contains(it) == true }.takeIf { it.isNotEmpty() }
+}
+
 @Deprecated("Unused")
 val JvmScriptCompilationConfigurationKeys.javaHome by PropertiesCollection.keyCopy(ScriptingHostConfiguration.jvm.javaHome)