[Pkg-d-devel] Installing libphobos2-ldc75

[Russel Winder]

Matthias,

Thank you for taking the time to do a detailed reply. This is very much
appreciated.

(For future reference: I have done a Meson build for dinotify, and am now
doing one for unit-threaded. I wonder if these could be added to the list of
libraries built for Debian Sid.)

> This is intentional, check the LDC changelog.

OK, that works for me. I will have to admit to have reacted to the "face
value" situation without having dug deeper into things. Having read the text
below I feel I now appreciate the problem… 

> While usually it is very discouraged to have library packages conflict
> (and most of the time a sign that you are doing something wrong), in
> this case it is justified because we want to ensure that the current
> LDC transition does not break the user's systems or unrelated
> packages.
> In the past it happened often that some packages up in the dependency
> chain (e.g. gtk-d) were compiled with newer versions of LDC, and some
> packages lower in the chain were still on the old version (e.g. tilix)
> which caused them to just break without notice for users who had
> updated their system. This was made worse by LLVM and LDC bugs which
> got packages stuck in this state for quite a long time.
> 
> By making the new Phobos library conflict with the old one, we ensure
> users do only update to the new LDC runtime packages when nothing on
> their system uses the old ones anymore, effectively ensuring we don't
> break anything for them with the transition.
> This is far from ideal (ideally D would have a stable ABI...), but
> IMHO it's better than the previous state.
> 
> At the moment this is an experiment, if we find serious issue with it
> we'll have to think of something else to fix this issue (but at the
> moment it's working as expected).
> Just wait for all the stuff to be rebuilt with the new LDC, and then
> you should be able to easily update to the new version.

…I guess the summary of problem here is handling the closure over the
dependencies to ensure consistency. Given the phobos, gtkd, tilix problem, it
is a wonder this is not a more widespread problem throughout Debian. Or maybe
it is and there is a solution there that isn't going to work for the D stuff.

In case it hasn't been said elsewhere: thank you for being a Debian maintainer
and getting ldc2, druntime, phobos, gtkd, and tilix into Debian Sid. I am not
in a position to be a Debian or Fedora maintainer myself, but appreciate the
work done by them. If there are things I can do to support, feel free to ask.

 
-- 
Russel.
==========================================
Dr Russel Winder      t: +44 20 7585 2200
41 Buckmaster Road    m: +44 7770 465 077
London SW11 1EN, UK   w: www.russel.org.uk
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