Feature Proposal: Rolling Updates (was Re: WHY I WANT TO STOP USING FEDORA!!!)

[Bill Davidsen]

Mark Haney wrote:
> Alan Evans wrote:

> No, I don't understandably say it's too bleeding edge.  I didn't say
> that at all.  But, I don't mind testing packages.
>> Fine. So packages in rawhide should be moved continuously into updates
>> as each is found worthy of general use? But how? If by the time the
>> kinks are worked out, the new package requires libfoo.9, then libfoo.9
>> will be updated to replace the libfoo.7 that's in updates. Now
>> everything that required libfoo.7 also has to be moved into updates.
>> But what if the kinks haven't yet been worked out of those programs?
>> And even if they were, one of those programs may now require
>> libbar.65, which forces that to replace libbar.56. This doesn't have
>> to go very far before it's not considerably different than making a
>> formal release. We've gained nothing, and the whole system is probably
>> much less stable.
> 
> See, that's my point.  There is no difference between 'yum update' and
> 'emerge -upD world' when you think about it.  When you update Fedora
> between release cycles, you're technically upgrading the system to a new
> version.  Whether it be a major or minor version is irrelevant for the
> point of this argument.  If the update to a package is not just a
> security update, but an /upgrade/ to a newer version, the OS is
> upgraded.  And let's not get into semantics here.
> 
No, this isn't semantics, there are four things involved here, not two:
- the OS is really just the kernel. In general you can update that
   without breaking everything. But if ACPI or similar changes, then
   some apps or scripts may fail.
- applications. Changes and upgrades to one application can be made
   freely, since they don't impact other things. Unless, of course, they
   need a change in...
- libraries. Changing a library means you have to control every application
   which uses the library. Since that may include user applications, non-
   Fedora applications, commercial databases, etc, that means that there is
   a very high chance of breaking things if a library is upgraded (as opposed
   to bug fixes, and other changes which don't change the API or behavior).
- the distribution. The things which make one Linux different from another,
   including package management, graphics, window manager, location of
   system files, graphics, system features like udev, SElinux, boot scripts
   and files, compilers and interpreters like C, perl, and python, and other
   things which have to all stay compatible with one another.

>> As I understand it, Gentoo doesn't suffer this because each user is
>> compiling their own package sets. Updating libfoo doesn't require
>> recursively redownloading every package that requires it because the
>> user already has the source to those programs. He just needs to
>> recompile them.
> 
> Explain to me how doing an update in Fedora requires the same method?
> If I update package 'appfoo' that requires 'libfoo' there's no
> difference between downloading and reinstalling the libfoo RPM along
> with the new version of 'appfoo' than it is recompiling libfoo in
> gentoo.  I /still/ have to download the source code to recompile it,
> unless I just happen to have that source (and it's not be updated)
> sitting in my portage cache.  The idea is the same, just a slightly
> different mechanism.  And with delta packages, this would be a cinch I
> would think.
> 
Compiling solves little, unless you mean compiling every application on the 
system each time you change a library in a non-trivial way. And of course if you 
change the compiler itself, there is no promise that multiple things don't 
break. Just look through the rawhide change listing and search for gcc, perl, 
and python, with notes like "fixed issue with gcc x.x.x" indicating that the 
application couldn't just be recompiled with the new compiler and library, 
source code changes were needed.

>> I just don't see how that can work in a general-purpose binary
>> distribution. Perhaps you have some ideas about how it can be
>> practically done that you haven't shared?
>>
> 
> See above.  Honestly, I've not delved deep into a feasibility study of
> this, but I fail to see a rational explanation for why it /can't/ be
> done.  It makes no difference to me if it /should/ or /will/ be done. I
> voiced my opinion and defended it fairly well (I think).  If the Fedora
> team never goes that route, it's no skin off my nose.  I will continue
> to use it like I have been since FC1.  I like it.  It's never been a
> pain to use (FF & NM not withstanding) and unless that changes for me
> I'm going to stick with it.
> 
Hopefully the above is deep enough delving to assure you that new releases from 
time to time are actually the least painful way to go.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot