Static destructors called before class instance destructors

[Tristam MacDonald]

Sean Kelly Wrote:

> rkreis wrote:
> > Good day.
> > 
> > Using derelict, I noticed bad behavior: The app segfaulted inside of 
> > destructors. I later found out that derelict unloaded libraries and the 
> > destructor, freeing resources, tried to call such unloaded functions. 
> > This happens because a static destructor unloads all libraries. A simple 
> > test case shows that static destructors can be called before all 
> > instances are destructed. If an instance destructor then uses resources 
> > freed by the static destructor, things become problematic.
> > 
> > import std.stdio;
> > 
> > class Dude {
> >     private static char[] eek;
> > 
> >     public this() {
> >         writefln("Dude ctor");
> >     }
> > 
> >     public ~this() {
> >         writefln("Dude dtor - eek is '%s'", eek);
> >     }
> > 
> >     public static this() {
> >         writefln("Dude static ctor");
> >         eek = "Everything up and running";
> >     }
> > 
> >     public static ~this() {
> >         writefln("Dude static dtor");
> >         eek = "You're doomed";
> >     }
> > }
> > 
> > void main() {
> >     Dude d = new Dude();
> > }
> > outputs
> > Dude static ctor
> > Dude ctor
> > Dude static dtor
> > Dude dtor - eek is 'You're doomed'
> 
> Funny, I've recently been trying to decide how to handle this exact 
> situation.  When a D application shuts down, unreachable objects 
> may/will be collected then static dtors are run.  After that, there may 
> still be valid D objects floating around, either which the GC 
> incorrectly thought were reachable or that were reachable through static 
> references.  Should these objects never be finalized?  This would 
> certainly be the easier/cleaner approach to take, but I'm not sure how I 
> feel about leaving objects un-finalized.
> Sean

DO they actually get finalised at the moment? I seem to have noticed that a lot of destructors aren't run at program termination, unless fullCollect() is explicitly called.