Error while debugging

[scriby]

This printed on the console, then the program exited with error code 134.

node: fibers.cc:440: static v8::Handlev8::Value Fiber::GetStarted(v8::Localv8::String, const v8::AccessorInfo&): Assertion `info.This()->InternalFieldCount() == 1' failed.

I was inspecting a variable with the debugger when it occurred.

Just thought I'd pass this along,

Chris

[laverdet]

Is there an easy way to repro this?

[scriby]

Here's how to reproduce:

1. Get a project set up with the asyncblock dependency
2. Run the following code (the exact code doesn't matter, but this works):

var asyncTask = function(callback) {
    process.nextTick(function() {
        callback(null, 1, 2, 3);
    });
};

asyncblock(function(flow) {
    asyncTask(flow.add());
    flow.wait();
});

1. I'm using the debugger built into the WebStorm editor, so if you can't reproduce in your environment, you might try installing it (it has a 30 day free trial)
2. Set a breakpoint on the asyncTask(flow.add()); line, and step in there
3. Once inside the asyncblock's flow.add method, try to inspect the contents of the "this" variable. I did this by right clicking -> evaluate expression -> "this" -> press enter -> expand the little triangle next to the variable
4. At this point, the error is printed to the console:

Assertion failed: (info.This()->InternalFieldCount() == 1), function GetStarted, file fibers.cc, line 440.

Thanks,

Chris

[laverdet]

Yeah this can be repro'd with:

var fiber = new Fiber(function(){});
var fiber2 = Object.create(fiber);
console.log(fiber.started);

Not really sure how to fix it though. The accessor is called but with the wrong this. I'd have to walk down the prototype chain to find the right one. Doesn't seem worth it.. I guess I could throw instead of crashing the application though.

[scriby]

Ok. I don't think it's that big of a deal assuming it only affects the debugger.