NullException with Async JS calls

[Bodekaer]

Hey @amaitland,

I sometimes get a null exception on this line:
https://github.com/cefsharp/CefSharp/blob/JsBinding_WIP/CefSharp.Core/ManagedCefBrowserAdapter.h#L433

I cannot easily replicate it, but perhaps you can easily see what it could be?

[amaitland]

@Bodekaer I'll update the method to at least gracefully handle the null, unsure first off about what could be causing it, I can clean it up a little. Does it happen frequently enough to know if it's been successfully fixed?

Soon as #492 is merged into master I can update the JS branch, the logging API has been exposed, so we can put in some logging deeper into the Cef side of things and hopefully see what's going on.

[Bodekaer]

Sounds good. Stability is most important for us at the moment, and if the null is just handled for now, that should be ok.
It happens usually every 2-3 days, so I'll be able to report after 1 week whether it's still occurring with a pretty good certainty.

[amaitland]

I've simplified the method, and handled the possibility of null for frame

Let me know what you think

amaitland@16f3bc4

[Bodekaer]

Looks good.
Then I can always handle the null that is returned.

Thanks.

[Bodekaer]

How about including error info in the JavascriptResponse perhaps?
In case frame is null, I wouldn't really know what happened.

E.g. I would need to write something like:
if (cefBrowser.EvaluateScriptAsync(...) == null) { handleError(null); };
Perhaps instead return an empty JavascriptResponse with error info.

[amaitland]

Sounds like a reasonable request.

[Bodekaer]

I've upgraded to the latest updates from your branch, and now I get a similar null exception, but in this line of code:
https://github.com/amaitland/CefSharp/blob/JsBinding/Wip2/CefSharp.Core/ManagedCefBrowserAdapter.h#L115

Here is the call stack:

CefSharp.Core.dll!.CefRefPtr.{ctor}(CefRefPtr* r) Line 157 C++
CefSharp.Core.dll!.CefSharp.Internals.ClientAdapter.GetCefBrowser() Line 56 C++
CefSharp.Core.dll!CefSharp.ManagedCefBrowserAdapter.OnInitialized() Line 115 C++
CefSharp.Core.dll!.CefSharp.Internals.ClientAdapter.OnAfterCreated() Line 47 C++

[Bodekaer]

It still only happens in rare cases, and so far I'm not able to reproduce it.
I believe it's related to disposing the browser - although in this case it happens during initialization which is strange.

[amaitland]

Strange!

I've pushed a couple more changes, most are cleanup as I'm going, relevant one to you should be this one
amaitland@6b542ba

Basically passing in BrowserId as a param, should have a valid reference to browser.

See how that goes?

[Bodekaer]

Cool thx. I'll test it out.

[amaitland]

@Bodekaer Any luck with the latest set of changes?

[Bodekaer]

Sorry, been busy last few days with launching this years PG event (http://www.projectgetaway.com/).
I'll be fully back to coding on Sunday, and test it all out there.

[amaitland]

No problem!

FYI: As per #496 (comment) we're going to release a stable version 33.0.0 without JS Binding and release 33.1.0-pre version including the JS Binding shortly after.

So just looking at any open issues that maybe relevant to this new -pre release.

[Bodekaer]

Ahh cool. It's ok. We're anyways compiling our own builds here for now (with smaller additions here and there)

[amaitland]

@Bodekaer Still experiencing problems?

[Bodekaer]

Nope. All good here. Thanks for the heads up.

[amaitland]

Cool cool, no problem.