Hi all,
Someone can explain me why the scope attribute of r2 is not satisfied? It's a bug or an expected behaviour?

Paolo

module tests.d.scopes.t02.test;

class Resource {
    static int allocated = 0;
    this( bool mustThrow = false ){
        allocated ++;
        if( mustThrow ) throw new Exception("bang");
    }
    ~this(){
        allocated --;
    }
}

void main(){


    // Why the destructor of r2 is not called when exiting the scope?
    {
        try {
            scope r1 = new Resource();
            scope r2 = new Resource(true);
        }
        catch(Exception e){}
    }
    //assert( Resource.allocated == 0); // Expected
    assert( Resource.allocated == 1 ); // What's happening

}

On Mon, 13 Oct 2008 13:50:46 +0400, Paolo Invernizzi <arathorn@fastwebnet.it> wrote:

> Hi all,
> Someone can explain me why the scope attribute of r2 is not satisfied? It's a bug or an expected behaviour?
>
> Paolo
>
> module tests.d.scopes.t02.test;
>
> class Resource {
>     static int allocated = 0;
>     this( bool mustThrow = false ){
>         allocated ++;
>         if( mustThrow ) throw new Exception("bang");
>     }
>     ~this(){
>         allocated --;
>     }
> }
>
> void main(){
>    // Why the destructor of r2 is not called when exiting the scope?
>     {
>         try {
>             scope r1 = new Resource();
>             scope r2 = new Resource(true);
>         }
>         catch(Exception e){}
>     }
>     //assert( Resource.allocated == 0); // Expected
>     assert( Resource.allocated == 1 ); // What's happening
> }

Looks like no destructor is called if ctor throws an exception.
Try throwing outside of it and see what happens.

On Mon, 13 Oct 2008 05:50:46 -0400, Paolo Invernizzi <arathorn@fastwebnet.it> wrote:

>Hi all,
>Someone can explain me why the scope attribute of r2 is not satisfied? It's a bug or an expected behaviour?
>
>Paolo
>
>module tests.d.scopes.t02.test;
>
>class Resource {
>    static int allocated = 0;
>    this( bool mustThrow = false ){
>        allocated ++;
>        if( mustThrow ) throw new Exception("bang");
>    }
>    ~this(){
>        allocated --;
>    }
>}
>
>void main(){
> 
> 
>    // Why the destructor of r2 is not called when exiting the scope?
>    {
>        try {
>            scope r1 = new Resource();
>            scope r2 = new Resource(true);
>        }
>        catch(Exception e){}
>    }
>    //assert( Resource.allocated == 0); // Expected
>    assert( Resource.allocated == 1 ); // What's happening
> 
>}

because r2 wasn't successfully created and there is nothing to call the destructor on:

class Resource {
    static int allocated = 0;
    this( bool mustThrow = false )
   {
        scope(success)
            allocated++;
        if( mustThrow ) throw new Exception("bang");
    }
    ~this(){
        allocated --;
    }
}

Denis Koroskin Wrote:

> Looks like no destructor is called if ctor throws an exception. Try throwing outside of it and see what happens.

In that case everything is ok. So it's a bug?

    // In this case everything it's ok
    {
        try {
            scope r1 = new Resource();
            scope r2 = new Resource();
            throw new Exception("bang");
        }
        catch(Exception e){}
    }
    assert( Resource.allocated == 0); // Expected

Max Samukha Wrote:

> because r2 wasn't successfully created and there is nothing to call the destructor on:

I think is more complicated... see this:

module tests.d.scopes.t02.test;

class Resource {
    static int allocated = 0;
    this( bool mustThrow = false ){
        allocated ++;
        if( mustThrow ) throw new Exception("bang");
    }
    ~this(){
        allocated --;
    }
}
class Factory {
    Resource resource(bool b=false){
        return new Resource(b);
    }
}

import std.gc, std.stdio;
void main(){
    // In this case everything it's ok
    {
        try {
            scope r1 = new Resource(true);
            assert( false );
        }
        catch(Exception e){}
        assert( Resource.allocated == 1);
        std.gc.fullCollect();
        assert( Resource.allocated == 1 );
    }

    Resource.allocated = 0;

    // In this case the destructor IS called, only on collect...
    {
        auto f = new Factory();
        try {
            scope r1 = f.resource(true);
            assert( false );
        }
        catch(Exception e){}
        assert( Resource.allocated == 1);
        std.gc.fullCollect();
        assert( Resource.allocated == 0 ); // Dho! Destructor called!
    }
}

On Mon, 13 Oct 2008 08:03:32 -0400, Paolo Invernizzi <arathorn@fastwebnet.it> wrote:

>Max Samukha Wrote:
>
>> because r2 wasn't successfully created and there is nothing to call the destructor on:
>
>I think is more complicated... see this:
>
>module tests.d.scopes.t02.test;
>
>class Resource {
>    static int allocated = 0;
>    this( bool mustThrow = false ){
>        allocated ++;
>        if( mustThrow ) throw new Exception("bang");
>    }
>    ~this(){
>        allocated --;
>    }
>}
>class Factory {
>    Resource resource(bool b=false){
>        return new Resource(b);
>    }
>}
>
>import std.gc, std.stdio;
>void main(){
>    // In this case everything it's ok
>    {
>        try {
>            scope r1 = new Resource(true);
>            assert( false );
>        }
>        catch(Exception e){}
>        assert( Resource.allocated == 1);
>        std.gc.fullCollect();
>        assert( Resource.allocated == 1 );
>    }
> 
>    Resource.allocated = 0;
> 
>    // In this case the destructor IS called, only on collect...
>    {
>        auto f = new Factory();
>        try {
>            scope r1 = f.resource(true);
>            assert( false );
>        }
>        catch(Exception e){}
>        assert( Resource.allocated == 1);
>        std.gc.fullCollect();
>        assert( Resource.allocated == 0 ); // Dho! Destructor called!
>    }
>}
>

I think this is a bug.