#1698 js: Exception handling is broken in Opera browser

mnasyrov Mon 14 Nov 2011

I have a simple code that throws an exception and catches it. But it does not work in Opera 11.52 and Fantom 1.0.60.

The source code:

echo ("Begin")
try
{
  throw ArgErr("Hello!")
}
catch (ArgErr e)
{
  echo("Error: " + e)
}
echo ("End")

I expect the following output in a browser console:

Begin
Error: sys::ArgErr: Hello!
End

But the browser throws a native exception, which is similar to the following:

Begin
Uncaught exception: 

Error thrown at line 27, column 6 in <anonymous function: fan.hello.helloApp.main>(args) in http://localhost:8080/pod/hello/hello.js:
    throw $_u1;
called from line 2, column 45 in <anonymous function: window.onload>() in http://localhost:8080/:
    fan.hello.helloApp.main();

Here is a compiled javascript code of the example:

fan.sys.ObjUtil.echo("Begin");
try
{
    throw fan.sys.ArgErr.make("Hello!");
}
catch ($_u1)
{
    $_u1 = fan.sys.Err.make($_u1);
    if ($_u1 instanceof fan.sys.ArgErr)
    {
        var e = $_u1;
        var e;
        fan.sys.ObjUtil.echo(fan.sys.Str.plus("Error:",e));
    }
    else
    {
        throw $_u1; // <-- THE EXCEPTION IS THROWN FROM HERE
    }
}
;
fan.sys.ObjUtil.echo("End");

It's a very strange behaviour. It seems like Opera prevents reassignment to $_u1 variable in $_u1 = fan.sys.Err.make($_u1); statement and keeps its original value. It may be enought to fix a "Fantom to JS" compiler" to use another variable to store an instance of Fantom's Error.

andy Mon 14 Nov 2011

Is this unique to Opera? Does it work properly in other browsers? Can you post some more debug:

try
{
  throw ArgErr("Hello!")
}
catch (Err e)
{
  echo("Error: $e.typeof")
}

mnasyrov Tue 15 Nov 2011

Yes, my example doesn't work in Opera and works in Chrome, Safari, FireFox and IE9.

Andy, Opera prints Error: sys::Err for your code, while other browsers prints Error: sys::ArgErr.

andy Tue 15 Nov 2011

Promoted to ticket #1698 and assigned to andy

andy Thu 8 Jun

Ticket cancelled

Cancelling since Opera is now based on Chromium

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