Re: fun with libgal

[Adrian Bunk <bunk@fs.tum.de>]

On Thu, 24 Jan 2002, Takuo KITAME wrote:

> AB> How do you want to solve the problems with inter-library dependencies?
>
> AB> Consider something like the following:
>
> AB> Package: evolution
> AB> Version: 1.0.1-1
> AB> Depends: libgal19, libgtkhtml20
>
> AB> Package: libgtkhtml20
> AB> Version: 1.0.0-1
> AB> Depends: libgal18
>
>
> AB> This means that evolution is linked with _both_ libgal.so.18 and
> AB> libgal.so.19. It might work in most cases but if you are unlucky there
> AB> might be run-time failures in the program (hint: libpng2 <-> libpng3).
>
> AB> As long as only one libgalXY package is in testing at a time this means
> AB> that this problem can't occur in testing.
>
> It can be resolved with Versioned Build-Depends.

Could you explain this a bit further, especially the problem when the
library gets compiled with a more recent version of libgal, e.g.:

Package: evolution
Version: 1.0.1-1
Depends: libgal19, libgtkhtml20

Package: libgtkhtml20
Version: 1.0.0-2
Depends: libgal19

This looks perfect, but what happens when libgal20 comes but no new
libgtkhtml21, but libgtkhtml20 gets recompiled with the more recent
libgal, IOW:

Package: libgtkhtml20
Version: 1.0.0-7
Depends: libgal20


How do you want to set up the build dependencies to ensure that:
- the above scenario can't happen
- in the case no new libgtkhtml gets released for a longer time (it's not
  important whether this is realistic for libgtkhtml, I'm interested in
  the general question) to make it possible to compile packages that need
  both libgtkhtml and a extremely recent version of libgal

?


TIA
Adrian