Re: [boost] [serialization] Support for multiple class name strings

From: Zach Laine (whatwasthataddress_at_[hidden])
Date: 2007-03-16 09:58:43

On 3/15/07, Robert Ramey <ramey_at_[hidden]> wrote:
> Zach Laine wrote:
> > I did something stupid with my serialization code.  I blithely changed
> > the names of several polymorphic classes everywhere they appeared in
> > the code, since they had moved out of a class into that class's
> > namespace (e.g. SomeNS::View::Primitive became SomeNS::Primitive).
> > Several months later, I discovered that I could no longer read old
> > binary archives, because I was using Boost.Serialization's
> > BOOST_CLASS_EXPORT() macro, and this macro was now registering the
> > Primtive type with the name-string "Primitive", instead of
> > "View::Primitive", which is how it was saved in the oldest archives.
>
> Ouch.
>
> > would it be technically possible to add a
> > BOOST_CLASS_EXPORT_ALIAS() macro, or some such?  If it is possible,
> > I'm willing to supply the implementation.
>
> I might be possible by hacking your own copy of extended_type_info.hpp.  I
> don't think
> we'd want to include such thing in the library.  So I would suggest:
>
> a) make the hack
> b) make small program which loads your old archives and creates new ones.
> This should be very easy.
> c) Forget this ever happened.

Why don't you want to include such a feature in the library?  I'll
probably go ahead and create the alias-aware patch I was talking about
before, and start using the patched version of Boost until I no longer
need to support the old data format.  Unfortunately, I'm not in a
position to reprocess all the old-format data.

Zach Laine