Re: [gentoo-user] A portage nuisance

[Alan McKinnon <alan.mckinnon@gmail.com>]

On 28/10/2017 19:58, Wols Lists wrote:
> On 28/10/17 15:52, Andrew Savchenko wrote:
>> On Fri, 27 Oct 2017 14:58:13 +0100 Peter Humphrey wrote:
>>>> On Fri, 27 Oct 2017 12:52:54 -0000
>>>> Helmut Jarausch <jarausch@skynet.be> wrote:
>>>>
>>>>>> I have a problem with emerge for a long time.
>>>>>> Sometimes I need to (re-)emerge many packages like in an
>>>>>> emerge --emptytree @world
>>>>>>
>>>>>> Because I use several overlays, there are problems with a lot of
>>>>>> packages.
>>>>>> Unfortunately, emerge shows me just the first problem (like a missing
>>>>>> USE-flags) and then terminates.
>>>>>> Is there any means to let emerge go and report several (all) problems
>>>>>> which are independent of each other?
>>>>
>>>> EMERGE_DEFAULT_OPTS="--keep-going" ?
>> No, --keep-going allows to continue as long as possible after a
>> build failure. Helmut asks about dependecies resolution failures,
>> e.g. in some package REQUIRED_USE is not met, or circular
>> dependency occurs and so on.
> 
> What I would like - a bit like --keep-going - is some option that tries
> again.
> 
> When I do an "emerge -u" it sometimes blows up with this massive load of
> dependency failures. So what I end up doing is emerge a few packages
> that look like they're going to work, and then try my full update again.
> After several cycles through this, suddenly everything works.
> 
> So my spec for what I would like is basically, as each package
> successfully resolves its dependencies, add it to a "try again" list. If
> the current list blows up in dependency hell, restart the emerge with
> just the packages in the "try again" list.


That is completely contrary to how portage is supposed to work and
produces an unpredictable result.

*You* know what you want and can do it, *you* are a human with a brain
who understands meaning.

Portage cannot do that, it is backed by silicon and has no concept of
meaning. So it has only one real choice - it can do it all or it does
not try.

I'm not surprised Zac never tried implementing partial graph resolution
for the very simple reason that if you try do it, you have no idea what
is going to be built. That is the opposite of what portage must deliver.
-- 
Alan McKinnon
alan.mckinnon@gmail.com