Re: [gentoo-dev] Portage dependency solving algorithm

[Jauhien Piatlicki]

08.11.14 22:47, hasufell написав(ла):
> On 11/08/2014 10:30 PM, Rich Freeman wrote:
>> On Sat, Nov 8, 2014 at 2:48 PM, hasufell <hasufell@g.o> wrote:
>>> On 11/08/2014 08:32 PM, hasufell wrote:
>>>>> Sorry to chime in like that but if you don't mind, I'd like to ask for a
>>>>> real-life example for badly declared dependencies with a few words why
>>>>> those are bad and how to make them actually better?
>>>>>
>>>>
>>>> from dev-haskell/hashtables (note "hashtables" != "hashable"):
>>>> || ( ( >=dev-haskell/hashable-1.1:=[profile?]
>>>>        <dev-haskell/hashable-1.2:=[profile?] )
>>>>      ( >=dev-haskell/hashable-1.2.1:=[profile?]
>>>>        <dev-haskell/hashable-1.3:=[profile?] )
>>>>    )
>>>>
>>>> Latest stable version of dev-haskell/hashable is 1.2.1.0.
>>>> On a stable system (arch) the paludis dep-solver will try to match the
>>>> first group first and realize that there is also a stable version
>>>> 1.1.2.5 that matches that group. At that point there is a correct
>>>> solution, but since that involves downgrading a package, it will require
>>>> user-intervention, because it may not be what the user wants.
>>>> (this is the easy scenario... if downgrading causes blockers, you get
>>>> much more interesting output)
>>>>
>>>
>>> To be more specific... it is assumed that hashable-1.2.1.0 is already
>>> installed. Every time the dep solver runs through those packages without
>>> specifying what you want, you will hit the downgrade-problem.
>>
>> I'm missing the problem.  The package requires one of two ranges of
>> hashable versions.  One of them is already installed.  The dependency
>> is satisfied.
>>
>
> The one that is installed (1.2.1.0) is *excluded* by the first group,
> but there is a valid version that fits instead (1.1.2.5).
>
> That's the point where the assumptions start about what the depstring
> means and what the user wants.
>

So the problem is only with intervals? First of all, maintainer would specify higher interval first here and it would solve a problem with possible downgrading. Second, || is rather not for such cases as you've said, so we could ask for a new syntax and solve this problem in the right way in one of the next EAPIs.

Are there any other problems in current model apart from intervals? I would really like to see a list of them all.

--
Jauhien