[mythtv-users] Upgrading from pre-0.22 MythTV versions

[f-myth-users at media.mit.edu]

    > Date: Mon, 26 Mar 2012 09:09:09 -0500
    > From: Kevin Kuphal <kkuphal at gmail.com>

    > On Sun, Mar 25, 2012 at 8:50 PM, <f-myth-users at media.mit.edu> wrote:

    > > I've been pondering this for a couple weeks, ever since I saw Mike's
    > > commit of 2012-03-09T15:20:56-08:00 and his message re "Upgrad failing
    > > from schema 1214 to 1265)" [sic].  This is a new thread 'cause I'm not
    > > sure if very late replies to old threads typically get seen.  Sorry if
    > > this is a bit long, but thanks for whatever you can clarify.
    > >
    > > I understand the problem with supporting old Myth versions if their
    > > surroundings also change, but can you be a little clearer on a few
    > > issues here?  And I'm hoping to perhaps change your mind, or at least
    > > get workable ways forward---maybe support old versions until 0.25 is
    > > released and -then- drop them, with more warning than the zero that
    > > such users got before your commit?

    > Cutting the below, can't you just upgrade to 0.23, 0.24, then 0.25 in order
    > using the tarballs?  I've seen that before in plenty of commercial products
    > and should work just fine here was well.

My impressions of why this wouldn't be easy:
(a) The tarballs are often not the latest release in any given major
    version.  Is it now the case that there are up-to-date tarballs
    for the latest of -fixes in "all" (for some definition of "all")
    Myth versions?  If not, what's the right source?  git?  svn?
    Does it vary based on the age of the release?
(b) Building requires grabbing a lot of dependencies.  That's -way-
    easier if you're starting with a package instead of a tarball,
    so you can do "apt-get build-dep mythtv" or whatever and be sure
    you actually have a consistent and compatible-with-itself set of
    supporting packages.
(c) Building old versions often winds up in dependency hell, so
    you often need to install an OS of the right vintage as well.
    Remember we're talking Qt versions, MySQL versions, maybe default
    charset issues, I dunno.  And that's ignoring capture devices,
    which I'm assuming one would -not- build except to get the backend
    to start, but that then requires a working dummy tuner or something
    else that most users never do, depending on how picky the backend
    is about starting enough to even upgrade itself.
(d) Many older distros either stop offering -everything-, or stop
    updating packages.  This means that someone trying to actually
    go the package route may wind up in trouble as well.

I can easily see just one of these causing a lot of hairpulling,
especially if done long after any given release/package/etc was
current---in some distros, it might not even be -possible- to go
back far enough.

Are these concerns invalid?

Here's another question:

Let's just take Ubuntu, since that's what I'm running.  For either
the Canonical-supplied packages or those from Mythbuntu, are those
routinely rebuilt for (for example, just 'cause it's an LTS) 10.04
against the -latest- -fixes?  Or once a package is generated for any
given old release, does it just ossify and only the latest-distro
version of Canon/MythB's packages get rebuilt?  Is there an easy way
to check?  [I ask about -latest- because of Mike's admonition to use
latest -fixes---presumably because of the bugfix that also caused him
to drop old schemas from master---which makes me assume that any
-fixes from before that wouldn't work, but master won't work -either-,
hence putting people between a rock and a hard place...]

[If older versions get very-latest-fixes, then at least it's possible
for someone who's currently paying attention to "stockpile" an entire
machine, physical or virtual, to enable a later upgrade, without
-also- having that stockpiled machine be able to build completely from
source.  But people who aren't on this list and are using Myth as an
appliance and haven't updated in years---often for very good reasons
---won't have done so until they get burned.  So the question then is,
what are their options?]