Why Jint.Runtime.ExecutionCanceledException can't be caught when calling anther engine's function

[Zaitonn]

here are my codes

public static readonly Dictionary<string, JsValue> VariablesExportedDict = new();

// export private variables for other engine calling
public static void Export(string key, JsValue jsValue)
{
    if (string.IsNullOrEmpty(key) || string.IsNullOrWhiteSpace(key))
    {
        throw new ArgumentException(nameof(key));
    }
    if (VariablesExportedDict.ContainsKey(key))
    {
        lock (VariablesExportedDict)
        {
            VariablesExportedDict[key] = jsValue;
        }
    }
    else
    {
        VariablesExportedDict.Add(key, jsValue);
    }
}

// a.js

serein.export('test', (x) => { serein.log(x) }); // export a function

// b.js

try {
    serein.import('test')(1)
} catch (e) {
    serein.log(e);
}

If the engine for a.js has disposed, the srcipt in b.js would throw an error because the origin engine of the exported function was not available.

But the try..catch statement can't catch the error successfully and throw an exception in C#. Here is some detail stack info

Jint.Runtime.ExecutionCanceledException: The script execution was canceled.
   在 Jint.Runtime.ExceptionHelper.ThrowExecutionCanceledException()
   在 Jint.Constraints.CancellationConstraint.Check()
   在 Jint.Engine.RunBeforeExecuteStatementChecks(Statement statement)
   在 Jint.Runtime.Interpreter.JintStatementList.Execute(EvaluationContext context)
   在 Jint.Native.Function.ScriptFunctionInstance.Call(JsValue thisArgument, JsValue[] arguments)
   在 Jint.Runtime.Interpreter.Expressions.JintCallExpression.EvaluateInternal(EvaluationContext context)
   在 Jint.Runtime.Interpreter.Expressions.JintExpression.GetValue(EvaluationContext context)
   在 Jint.Native.Function.ScriptFunctionInstance.Call(JsValue thisArgument, JsValue[] arguments)
   在 Jint.Engine.<>c__DisplayClass93_0.<Invoke>g__DoInvoke|0()
   在 Jint.Engine.ExecuteWithConstraints[T](Boolean strict, Func`1 callback)
   在 Serein.Core.JSPlugin.JSFunc.<>c__DisplayClass5_0.<SetTimer>b__0(Object _, ElapsedEventArgs _) 位置 C:\GitHub\Serein\Serein\Universal\Core\JSPlugin\JSFunc.cs:行号 159

As I expect, the engine should catch it and convert it into js error which should be caught. Is it a bug or a feature specially designed?

Looking forward to your reply :D
tkx

[lahma]

You need to configure engine's options ExceptionHandler.

jint/Jint/Options.cs

Lines 291 to 297 in 8b0da8a

	/// <summary>
	/// Exceptions that thrown from CLR code are converted to JavaScript errors and
	/// can be used in at try/catch statement. By default these exceptions are bubbled
	/// to the CLR host and interrupt the script execution. If handler returns true these exceptions are converted
	/// to JS errors that can be caught by the script.
	/// </summary>
	public ExceptionHandlerDelegate ExceptionHandler { get; set; } = static exception => false;

[lahma]

Can you write a xUnit test case showing the problem?

[Zaitonn]

I'm sorry that I'm not familiar with it :(

but i can give you my code

const {
    Drawing: {
        Bitmap,
        Graphics,
        Color,
        StringAlignment,
        StringFormat,
        Font,
        SolidBrush,
        RectangleF,
        Imaging: {
            ImageFormat
        }
    },
    IO: {
        File,
        Directory
    },
} = System;


function generate(text) {
    let img = Bitmap.FromFile('plugins/xibao/QQ图片20230202230157.jpg');
    if (!Directory.Exists('plugins/xibao/output'))
        Directory.CreateDirectory('plugins/xibao/output');
    let g = Graphics.FromImage(img);
    let format = new StringFormat();
    format.Alignment = StringAlignment.Center;
    g.drawString(text, new System.Drawing.Font("黑体", 30), // the error may be thrown when executing this line
        new SolidBrush(Color.Black),
        new RectangleF(2, 132, img.Width, 300),
        format
    )
    g.drawString(text, new System.Drawing.Font("黑体", 30),
        new SolidBrush(Color.Red),
        new RectangleF(0, 130, img.Width, 300),
        format
    )
    let file = `plugins/xibao/output/1.png`;
    img.save(file, ImageFormat.Png);
    img.Dispose();
}

generate("测试");

in 2048 it can successfully generate an image but 2049 not
I’m sure I have allowed the System.Drawing assembly

[lahma]

How did you configure the engine?

[Zaitonn]

https://github.com/Zaitonn/Serein/blob/a94e0cbe8477388826af82ab2ed7efaa6c3416aa/Serein/Universal/Core/JSPlugin/JSEngine.cs#L40-L77

the preloadconfig is designed for developer to configure the engine indirectly (it allows developer to determine which assembly should be loaded in the engine)

[Zaitonn]

can you reproduce it now?

[Genteure]

一个基于.NET 6和NET Framework 4.7.2的新时代我的世界极简服务器面板

Which runtime are you using at this time and how are you referencing System.Drawing?

[Zaitonn]

Which runtime are you using at this time

both net6.0 and net472
两个都用了 但是两个效果一样，都是报错

how are you referencing System.Drawing?

https://github.com/Zaitonn/Serein/blob/a94e0cbe8477388826af82ab2ed7efaa6c3416aa/Serein/Universal/Core/JSPlugin/JSEngine.cs#L40-L77

Read a config json file before reading the js file, and the config will provide a array of assemblies which should be loaded when initing a new engine
finally use cfg.AllowClr(params Assembly[])

先读个json文件确定这个新的js引擎的配置以及要加载的程序集名称，然后通过名称用System.Reflection.Assembly.Load获取到Assembly对象丢进一个列表里，最后转成数组传参给cfg.AllowClr(params Assembly[]) 是有点麻烦了（卑微