Constraints do not work correctly when using ScriptFunctionInstance.Invoke

[dmsch]

I tried using ScriptFunctionInstance.Invoke to call Javascript callbacks from C# but get MemoryLimitExceededException or TimeoutException when called multiple times, although this, at least I think, should not be the case.

Example which throws MemoryLimitExceededException :

var engine = new Engine(options => { options.LimitMemory(1_000_000); });
            
engine.Execute("var callback = function(arg) {}");
var callback = engine.GetValue("callback") as ScriptFunctionInstance;
var testData = "Lorem Ipsum Dolor Sit Amet";
            
for (int i = 0; i < 100000; i++)
{
      callback.Invoke(testData); // Throws MemoryLimitExceededException after 2258 iterations.
}

Example which throws TimeoutException:

var engine = new Engine(options => { options.TimeoutInterval(TimeSpan.FromSeconds(5)); });
            
engine.Execute("var callback = function(arg) {}");
var callback = engine.GetValue("callback") as ScriptFunctionInstance;
var testData = "Lorem Ipsum Dolor Sit Amet";
            
for (int i = 0; i < 10; i++)
{
     callback.Invoke(testData); // Throws TimeoutException after 5 iterations
     Thread.Sleep(1000);
}

Is the ScriptFunctionInstance.Invoke method meant to be called externally, or would I be better off using Engine.Invoke instead?

[lahma]

Generally it's always better to route calls through Engine instance. Engine knows how to reset state between calls.

You could even go one step further and set the testData as variable into engine and then call engine.Evaluate("callback(testData)"), that's something I find a natural way to interact.

[lahma]

If it was up to me I'd probably remove other methods than Evaluate and Execute for running JS code, other ways tend to get tricky 🤷🏻‍♂️

/cc @sebastienros

[lahma]

Maybe Invoke would make more sense if it would allow only string as first parameter (the target), dunno. @dmsch how does engine.Invoke("callback", testData) behave in this case?

[dmsch]

engine.Invoke("callback", testData) also throws these Exceptions.

Created an example that shows why I tried to call the callbacks directly: https://gist.github.com/dmsch/5a243ea5352bfb5cc1f3322481f95b0e

[lahma]

Now also Invoke should follow set constraints properly: #986

[dmsch]

@lahma Thanks for the change.
This library is top-notch.