Removing single program from multi program packages

[John Carr]

2009/3/23 Mike Jones <eternalorb at gmail.com>:
> Hi guys. Thanks for your detailed replies.
>
>     I think I'm having a difficult time expressing what I'm trying to get
> across. It's kind of a vague notion.
>
>     My problem isn't that for me its difficult to either just remove the
> package entirely (in this case, I don't play any of those games and don't
> see a situation where I will want to for the foreseeable future. If it
> decide I want to, I will simply install the package again.) I understand
> that I can go to the terminal and remove or modify the portions of the
> system I want to manually. (I recommend that you not suggest that to anyone
> in the future. 60% of my time using Ubuntu is in a terminal, and I am more
> than aware that mucking around in the system is a *bad* idea. I don't know
> what files to modify in what order, and I doubt that it would be easy to
> find the information within 5 minutes).
>
>     The problem isn't that the space required for these packages is
> bothersome. I'm fortunate enough to have relatively new hardware and plenty
> of storage. The space needed for those extra games is effectively trivial
> for me.
>
>     In terms of repackaging the programs: I am more than appreciative of
> those who spend their time packaging programs for Ubuntu. Even those who
> package programs I don't use are appreciated. You're right. It would be
> futile for me to repackage the collection of programs for my own personal
> use. That would be silly.
>
>     So I wanted to emphasise that I'm not a nieve user. I am a Software
> Engineering student, and spend a large amount of time doing software
> development at my job. I know a decent approximation of how the various
> components that I concern myself with work. Well enough to know what I need
> to look up, anyway.
>
>     I think I really wanted to get across was "Whats keeping
> apt/aptitude/gdebi/synaptic/add-remove/ what-have-you from being able to
> cherry pick components of a package? Is there some hard and fast technical
> limitation? Would anyone like to offer suggestions to me for where I can
> look into improving the system? Is it feasable to do so?" Any time my tools
> (In this case add-remove, or the other front-ends for the package manager)
> tell me I can't do something I know I should be able to do, I'm bothered. A
> non-advanced user is going to see that message reply and say "Well why the
> hell can't I remove one of them? Just delete it!" I know they will. I heard
> my brother screaming that the other day when he couldn't remove who knows
> what. It is non-intuitive to not be able to remove or add single programs,
> and instead be told to install entire packages. I understand the realistic
> reasons why this is so, but it doesn't stop me from gritting my teeth from
> what I see as an annoyance.
>
>     I think that I was able to get myself across a little better. Let me
> know if I was confusing still.
>
> -Mike
>
> On Mon, Mar 23, 2009 at 9:43 AM, Loïc Martin <loic.martin3 at gmail.com> wrote:
>>
>> Mike Jones wrote:
>>>
>>>    Is there just no way for a package maintaner to not have extra work
>>> piled on their already hefty load while at the same time we allow a user of
>>> Ubuntu to remove most traces of a program in a package with multiple
>>> programs without having to also remove the rest of them? Is it worth doing
>>> even if its possible? I think I'm in a somewhat unique position of having
>>> extreme distaste whenever my system tells me I can't do something in a
>>> counter intuitive way.
>>
>> You can remove the program and keep the other ones in the package actually
>> - nothing is preventing you to do so, even the system. The cleanest solution
>> would be for you to repackage gnome-games (or whatever name the package is
>> called) for your personal use, while excluding the programs you don't want.
>>
>> Quite a lot of work for absolutely no gain, but could we expect Ubuntu
>> developers and package maintainers to spend days doing that for us while we
>> wouldn't spend the same amount of time ourselves (including the time
>> googling for howtos and such)? Especially when they already have far more
>> critical bugs to address (like when the programs don't even run, or when
>> people can't install Ubuntu or run it on their machines ;) ).
>>
>> But all in all, nothing is preventing you to do what you want to achieve.
>>
>> Fact is, the way it's done now allows easy upgrades for millions of people
>> who are quite please to see the selection of programs updated for each
>> release, while said programs only take a few kb of space on their drives.
>> And to be fair, when people are complaining they can't remove foo without
>> removing bar or ubuntu-desktop, I always wonder why they point to programs
>> that only takes a few kB of space while being oblivious to the hundreds of
>> MB taken by fonts, translations, libraries, system utilities, drivers...
>> they'd never use in a lifetime, but that are invaluable because they make
>> peripherals, foreign languages documents and other things work out of the
>> box in Linux.
>>
>> For space-constrained drives, there's Damn Small Linux, and if we were
>> shooting for that goal I'm not so sure you'd find so many developers and
>> packagers in Ubuntu.
>>
>> If unused programs are really an issue but you're not so tight on space to
>> use DSL, the Ubuntu server install could probably address your needs better
>> - just chose all the programs that you need one by one, and you'd  end up
>> with far less programs than you'd have just trying to get rid of individual
>> programs in multi-program packages that show in the menus. Such a difference
>> it wouldn't be funny.
>>
>> Loďc

Hi Mike

Cherry picking parts of a package is bad for the same reason that
going in and using rm by hand is bad. The goal of the package manager
is to keep your system in a sane state and allow you add, remove and
update things without making it so you cant boot. But with cherry
picking, the package manager has no way of knowing if you removing
part of a package means that another package or another application or
library within the current package will carry on working.

So could synaptic automatically work out the dependencies? Well maybe
for applications it can see what libraries are linked against. And
maybe it can scan for files that are referenced. But i think there
will always be things it cant resolve, it will always be a bit fragile
etc. So humans will have to maintain the data that describes these
'sub packages'.

Of course you can disregard the above paragraph because deb packages
already support this. You have a single source package and it can
build the tarball and then there are .install files that say 'these
files belong with this game, and these files belong with this game'.
Each install file is just a list of files that the build process made
that belong in a given package. Then you get exactly the behaviour you
want, safely. But its more work for the maintainers, as already
described.

Does that make sense? This is not a technical limitation of the
packaging format, more of a limitation of man power.

John