QScriptEngine::popContext crash

[tonka3000]

Hy@everybody,

i have some troubles with the QScriptEngine and the context. I have a simple script (originally written in coffeescript). I call these script with the engine (with a new pushed context) and i get an crash after popContext().
The script is a simple recursive function which call itself 1000 times. I have created much more complex apps with QtScript and never had problems like these!

// Generated by CoffeeScript 1.7.1
(function() {
  var param1, recursive;
 
  param1 = 0;
 
  recursive = function() {
    param1 = param1 + 1;
    if (param1 < 1000) {
      return recursive();
    }
  };
 
  recursive();
 
}).call(this);

// Generated by CoffeeScript 1.7.1
(function() {
  var param1, recursive;

  param1 = 0;

  recursive = function() {
    param1 = param1 + 1;
    if (param1 < 1000) {
      return recursive();
    }
  };

  recursive();

}).call(this);

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My cpp code is very simple:

QScriptEngine engine;
QScriptContext* newContext = engine.pushContext();
engine.evaluate(jscode);
engine.popContext(); // after this point it crashes!

QScriptEngine engine;
QScriptContext* newContext = engine.pushContext();
engine.evaluate(jscode);
engine.popContext(); // after this point it crashes!

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It crashes after engine.popContext(). I need the context to avoid variables in the global-object by default (and this snippet worked the last 2 months).

If i change the recursive counter in the script from 1000 to 10, it works well.

Working script:

[CODE]// Generated by CoffeeScript 1.7.1
(function() {
  var param1, recursive;
 
  param1 = 0;
 
  recursive = function() {
    param1 = param1 + 1;
    if (param1 < 10) {
      return recursive();
    }
  };
 
  recursive();
 
}).call(this);

[CODE]// Generated by CoffeeScript 1.7.1
(function() {
  var param1, recursive;

  param1 = 0;

  recursive = function() {
    param1 = param1 + 1;
    if (param1 < 10) {
      return recursive();
    }
  };

  recursive();

}).call(this);

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[/CODE]

I can reproduce this problems with 4.7.3 and 4.8.5 (i have not tested 5.x yet). I'm on a Windows 7 x64 SP1 machine with Visual Studio 2010 SP1 compiler.

Does anybody has this problem?
Can anybody reproduce this error on your windows/linux/mac machine?

BTW: This code works perfectly in node.js

Thanks in advance
Tonka

[anda_skoa]

It would be easier to try reproducing it if there was something to compile and run.

Cheers,
_

[tonka3000]

Hy anda_skoa,

i've write a simple console-program with an example script. At the moment (weekend) i've only have a mac and Qt 5.2, and here it is working.

I've add the QtCreator project to this thread.
The first argument of the app has to be the script-file.

Thanks for your help

Greetings
Tonka

[anda_skoa]

Works for me on Linux, 64bit, with both Qt 4.8.6 and 5.3.1

Cheers,
_

[tonka3000]

Thanks for testing. I think thats a windows only problem.
I hope somebody could test my example on a windows x64 system.

Greetings
Tonka

[ars]

Fails on windows 7, 64 bit with TDM GCC 4.8, 64 bit and Qt 4.7.3. Reducing the recursion to 814 in the js file gives success (recursion >= 815 gives failure).

Works without problems on linux 64 bit (gcc 4.8 and Qt 4.8.5).

Regards
ars

[wysota]

What is the backtrace upon the crash?

[tonka3000]

Ars, thanks for testing. It seems that this bug is only in windows (and I think only in x64).

The strangest thing about this error is that the script runs to the end, and then it breaks. At Friday I have debug this bug a little bit and seems that the callframe of the JavaScript Core is broken, but I can't find a reason why.

If I remove the context push (and pop), nothing breaks (but without the context I get garbage in my global object).

Does anybody know if it works in ein x86?

Greetings
Tonka

---

Added after 31 minutes:

There is an bugfix in qt 4.8.6 which solve some memory problems with recursiv function. Maybe this will fix the crash (could not test it myself before monday)

Greetings
Tonka

[wysota]

Have you tried simply replacing the global object and setting the original one as its prototype instead of using contexts?

[tonka3000]

wysota, thats an interresting idea, i will try that on monday.
Thanks

[tonka3000]

I've created a github-repo for the testapp https://github.com/tonka3000/QtScrip...iveFunctionBug

I've rebuild this bug on the following versions on windows

* 4.7.3 x64 (MSVC 2010 SP1 x64)
* 4.8.5 x86 (from Qt-Project.org MSVC2010)
* 4.8.6 x86 (from Qt-Project.org MSVC2010)
* 5.3.2 x86 (from Qt-Project.org MSVC2010)

In the next view days i try to implement my own context-system (with the global-object change tip from wysota).
I also will open a bug-report on the offical qt-bugtracker.

Greetings
Tonka

---

Added after 24 minutes:

here is the link to the bug-report on qt-project.org
https://bugreports.qt-project.org/browse/QTBUG-41558