[OE-core] [PATCH 7/8] busybox: Put klogd/syslogd alternative links in syslog package

[Mark Hatle]

On 9/6/18 5:51 PM, Richard Purdie wrote:
> Just to follow up, I'm trying separating out busybox-syslog's
> recommends from busybox into the higher level packagegroups. The patch
> is in -next and will run tests overnight.
> 
> Doing this is probably good anyway but it does feel like we're working
> around an rpm/dnf issue. I'm open to better ideas...

Circular dependencies can result in non-deterministic behavior.  RPM does not
have any difference in dependency resolution (ordering) for depends vs
recommends.  (The only difference is a recommend is not an error.)  Due to this,
a circular dependency will result in behavior that may change the order of
circular dependent items based on external factors such as file list order, date
codes or ???

RPM does (or at least used to) permit you to specify a way to break circular
dependencies.  But this was a static list of known circular dependencies which
you would simply specify in the macros file which had to be installed first.

The 'correct' way to break this is only specify ACTUAL dependencies, and
realistically there should never be a circular dependency based on a pre-post
install action.  Otherwise, expect non-deterministic breakage.

There is also a way to explicitly set dependencies for the install scriptlets
themselves, but I don't know how this influences the ordering of the
installation.   But this would likely require some special syntax for busybox
(or other early load environments) which likely would be worse then a package group.

(I don't know how or if DNF handles this differently BTW.)

--Mark