Throwing InvalidMemoryOperationError

[Etienne Cimon via Digitalmars-d]

On Thursday, 4 June 2015 at 16:49:07 UTC, Adam D. Ruppe wrote:
> On Thursday, 4 June 2015 at 16:32:39 UTC, Etienne Cimon wrote:
>> Wouldn't that be with `this() in { assert() }` ?
>
> Not necessarily. Consider something like a file wrapper, if 
> fopen is null inside the ctor, you'd generally throw on that.
>
>> My concern is the fact that the destructor won't be called. Or 
>> will it?
>
> It won't be for deterministic objects (structs on the stack) 
> but is for GC'd objects (eventually).
>
> I don't think it should be called since if the constructor 
> fails, the object doesn't really exist and there's nothing to 
> destroy. You can reliably clean up intermediate things in a 
> constructor using scope(failure):
>
> struct Foo {
>    FILE* file, file2;
>    this(something somename) {
>         file = fopen(somename);
>         if(file is null) throw FileException(somename);
>         scope(failure) { fclose(file); file = null; }
>         file2 = fopen(somename2);
>         if(file2 is null) throw FileException(somename2);
>    }
>    ~this() {
>       if(file !is null) fclose(file);
>       if(file2 !is null) fclose(file2);
>    }
> }
>
>
>
> That'd work whether the destructor is called automatically or 
> not and isn't too hard to write since scope(failure) is pretty 
> convenient.

Nice, I'll try and use that once I find the reason I get this 
error:

https://travis-ci.org/etcimon/botan/jobs/65410185#L426

Somewhere random in a 100k line code base, a deadlock is 
triggered in the GC by some object's destructor. :/