[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Are circular dependencies inside a source package OK?

[Lucas Nussbaum]
> However, that creates many small dependency cycles. I am under the
> impression that dependency cycles are considered bad, but that we
> have many of them already, and that no important part of our
> infrastructure or tools really has problems with them. Also, they
> are limited to a single source package here.
> Is there a good reason not to do the above?

Dependency loops tend to break in edge cases, and I have run into a few:

 - Installing a lot of packages (~1000 packages done by Debian Edu), a
   while back caused the set of packages to be installed to be split
   into lumps, and some times this installation would fail because the
   split would happen in the middle of such loop.  I believe a
   workaround/fix for this has been implemented, but do not know the

 - When installing several packages and one of the packages fail to
   install, the recovery system for dpkg/apt fail and leave the system
   in an inconsistent state because only some of the packages in such
   loop have been unpacked and configured.

 - Piuparts is not able to come up with a sensible order to test
   packages when there are dependency loops.  A workaround has been
   implemented.  Suspect packages with loops are simply never tested
   by piuparts

All of these issues might of cause be seen as not important parts of
our infrastructure or not important problems, but I believe they are
enough to still consider package dependency loops a bad idea.

Are there other problems with dependency loops?

Happy hacking,
Petter Reinholdtsen

Reply to: