Add Throwable.toString(sink) overload

[MartinNowak]

Add toString(sink) overload to Throwable, so that it can be used without the GC.

[IgorStepanov]

I hope, we'll remove this file in #482 :)

[ghost]

I thought the plan was to remove stuff from the Object class? Note that if you already had this toString in your class you're now forced to make it virtual. It may or may not be an issue.. Since Object is rarely (if ever) used in user/library code I don't see why we need to introduce virtuals.

[MartinNowak]

It's Throwable not Object.
The point here is that Throwable can't use the default Object.toString method because that requires a working GC. So instead this pull switches to a sink method.
Old code that only overrides string toString in exception classes will continue to work as before but this pull makes it possible to use custom messages even for uncatched Throwables.

[ghost]

Ah, I misread. Sorry.

[ghost]

buf is dead code.

[MartinNowak]

thx, done

[ghost]

Other than the small issues this LGTM.

[ghost]

Thanks.

[jacob-carlborg]

The commit db7dc40 causes problems with unit test failures.

extern (C) int printf (in char*, ...);

unittest {
    printf("Reached unittest.\n");
    assert(0);
    printf("After failed assertion.\n");
}

void main ()
{

}

The above code should print:

Reached unittest
core.exception.AssertError@main(7): unittest failure

And a stack trace. After the above mentioned commit it only prints "Reached unittest.". See http://forum.dlang.org/thread/lgxkcylkpugpktpstpgh@forum.dlang.org#post-lgxkcylkpugpktpstpgh:40forum.dlang.org.

[jacob-carlborg]

Reported as: http://d.puremagic.com/issues/show_bug.cgi?id=11362.

[ghost]

Argh, so we had no stack-trace tests before? Even some partial string matching could suffice.

Anyway @dawgfoto, any ideas what went wrong?

[complexmath]

It looks like no one updated core.exception, so all the standard exceptions may have lost their custom error messages. The exceptions defined there all override toString() only. Also, what about exceptions defined in Phobos? Have any of those been updated to work with this new output routine?

[MartinNowak]

It looks like no one updated core.exception, so all the standard exceptions may have lost their custom error messages.

AFAIR this only changed how uncatched exceptions were printed, they didn't show custom messages before because it's not possible to use toString without a GC.
I agree, that more exceptions should be changed to use the new sink overload.

[MartinNowak]

Can you please file a bugzilla ticket for this?

[complexmath]

Uncaught exceptions are handled before static module dtors are run and before the GC is terminated though. Custom messages should have worked up until this change. I'll file a ticket.