scriptenengine重用参数?

Question

我一直在遇到Kotlins JSR-223实现ScriptEngine的奇怪问题(kotlin-scripting-jsr223)

基本上，我有一个条件，我解析并编译成一个CompiledScript:

fun parse(clazz: KClass<out GenericEvent>, condition: String): String {
val simpleName = clazz.simpleName
return """
import ${clazz.java.name}

val condition: $simpleName.() -> Boolean = { ${trimQuotes(condition)} }

fun check(event: $simpleName) = condition.invoke(event)

""".trimIndent()
}

然后我使用(engine as Compilable).compile(code)将结果字符串编译成CompiledScript。

现在，每当我尝试在很短的时间内多次eval()这些CompiledScript时:

listener.compiledScript.eval()
return@Callable (engine as Invocable).invokeFunction("check", event)

似乎重用了以前使用过的旧参数。首先，我认为这是一个线程安全问题(因为它看起来很像一个)，但是使用互斥锁或单线程执行器来编译脚本并没有改变这种行为。

完整代码:

override suspend fun onEvent(e: GenericEvent) {
val events = listeners[e.javaClass] ?: return
events.forEach { listener ->
try {
val event = e.javaClass.cast(e)
if (listener.compiledScript != null) {
val result = executor.submit(Callable { // executor = Executors.newSingleThreadExecutor()
println(Thread.currentThread().id) // confirms it's always the same thread
listener.compiledScript.eval()
return@Callable (engine as Invocable).invokeFunction("check", event)
}).get()
if (result is Boolean && result)
listener.method.callSuspend(listener.instance, event)
} else {
listener.method.callSuspend(listener.instance, event)
}
} catch (throwable: Throwable) {
log.error("An error occurred while evaluating listener condition!", throwable)
}
}
}

一开始，这是预期的

Condition: message.contentRaw == "first"
Is actually: first

，但它创建了奇怪的，但总是相同的模式。

Condition: message.contentRaw == "first"
Is actually: second
Condition: message.contentRaw == "second"
Is actually: second
Condition: message.contentRaw == "first"
Is actually: second
Condition: message.contentRaw == "second"
Is actually: second
Condition: message.contentRaw == "first"
Is actually: second
Condition: message.contentRaw == "second"
Is actually: second

(如果条件不为真，则不应打印这些消息)

我之前做了一些调试，我在编译的代码中打印了条件和实际事件，它确实重用了check()中前面的事件参数，尽管我实际上使用了一个完全不同的参数。

Answer 1

通过创建新的SimpleScriptContext，将其传递给CompiledScript的eval()方法，然后在调用invokeFunction()之前使用新创建的上下文调用ScriptEngine#setContext来修复它

疯狂的东西!