[Fedora-packaging] Re: Proposal to limit file deps

[Fernando Nasser]

Toshio Kuratomi wrote:
> On Thu, 2006-12-21 at 12:13 -0500, Fernando Nasser wrote:
>> Rex Dieter wrote:
>>> Fernando Nasser wrote:
>>>> I have two questions:
>>>>
>>>> 1) If this is a problem that only affects yum and all the other 
>>>> depsolvers do it efficiently, would it be better to fix yum instead or 
>>>> working around it by spec file changes?
>>> It's still generally a good idea to minimize file deps.
>>>
> Actually, what's happening is that all depsolvers have the ability to
> optimize two time consuming steps if the file deps follow these
> guidelines.  The two steps are 1) downloading filelist.xml.gz and 2)
> parsing filelist.xml to find the package which provides the file deps.
> [And this problem is multiplied the more repositories you have defined
> as the depsolver will have to grab the filelist.xml file from multiple
> repositories].
> 
> Panu points out that only yum currently optimizes this but there's
> nothing stopping the others doing it as well.
> 

OK

>> Sure, but there are cases where it is desirable.  I am afraid a dull 
>> guideline will put a straight jacket on developers.
>>
>> For instance, I know a couple of folks working on a software that in the 
>> current release needs two independent packages.  Another developer needs 
>> one (a single one) file from them, but the file may change places.  They 
>> thought of adding a virtual provides, but it seems overkill in this case 
>> and it is probably only temporary (which would mean we would use a name 
>> unnecessarily and regret later). So the best way around it was to 
>> require the file, at least until the set of packages stabilize on a 
>> future version of the dependency.
>>
>> Perhaps a "recommendation" guideline?  (if there is such a thing)
>>
> Yes.  This proposal is for a "Should" rather than a "Must" guideline.
> In the case you outline, I'd like to see the package depend on the file
> until it was settled which package would provide it.  Then the
> dependency could be converted to a package dep instead.  We don't
> currently have an ongoing QA requirement, though, so remembering to make
> the change would largely be the responsibility of the packager.
> 

That will work for them.  I think it is a sensible approach.
Perhaps adding a FIXME to the specfile above that dependency would be a 
good idea.

>>>> 2) If we still use file deps for things in /bin /sbin /usr/bin 
>>>> /usr/sbin, which happens for all GCJ compiled packages, wouldn't it 
>>>> force the reading of the second file anyways?
>>> No, just for items *outside* of those locations does yum need extra 
>>> processing.  That's the whole point of this exercise.
>>>
>> Ah, thanks for the clarification.  The use of file deps prevents an 
>> optimization to kick in.
>>
> Correct.
> 
>> Is this list complete: /bin /sbin /usr/bin /usr/sbin ?
>> Or there are others that do not cause the loading of the second file?
> 
> /etc is the other one.
> 

Thanks.  I guess the list of exceptions will be in the guidelines.

> That's why the guideline applies to file deps outside
> of /etc /bin /sbin /usr/bin and /usr/sbin.
> 
> -Toshio
> 
> 

Thanks for the clarifications

Fernando