Re: [gentoo-portage-dev] [PATCH] emerge(1): document --oneshot caveats (bug 563482)

[Zac Medico <zmedico@gentoo.org>]

On 10/21/2015 09:13 AM, Rob Wortman wrote:
> On 2015-10-20 at 22:11:24 -0700, zmedico@gentoo.org wrote:
>> Any packages that are not reachable from @world are ripe for removal by
>> --depclean, so we allow their dependencies to break in order to satisfy
>> other dependencies (like in bug 563482). If you don't use --deep, then
>> emerge may try to build something that depends on one of these
>> unreachable packages with broken dependencies, such that whatever you
>> are trying to build has broken indirect dependencies (which is likely to
>> trigger a build failure like in bug 563482).
> 
> I think I understand. So, one could get the hypothetical scenario:
> 
> # emerge --oneshot A # which depends on B
> # emerge --update @world # shuffles stuff around breaking B
> # emerge C # which depends on A
> 
> Package C's dependency is filled, so emerge goes ahead and builds C.
> Now, either C fails to build, or it is installed but fails at runtime,
> because it depends on a package which depends on a package which is
> broken.
> 
> Sound about right?
> 

Yeah, and if you run emerge --depclean regularly, then it will prevent
problems like these.
-- 
Thanks,
Zac