On Wed, Oct 19, 2011 at 23:37, Bob Proulx <b...@proulx.com> wrote:
>> > Control files: lines which differ (wdiff format)
>> > ------------------------------------------------
>> > Depends: m17n-db (>= [-1.5.0)-] {+1.6.3)+}
>> > Description: [-a-] multilingual text processing library - contributed
>> > database
>> > Installed-Size: [-1400-] {+1184+}
>> > Recommends: libm17n-0 (>= [-1.5.0)-] {+1.6.3)+}
>> > Version: [-1.1.12-2-] {+1.1.13-1+}
>>
>> The Recommends here is the bad thing:
>> Currently libm17n-0 is only available in 1.6.2-3 -
>> this means with an upgrade of m17n-contrib now we would break
>> a previously satisfied Recommends which means the user might loose
>> functionality without expecting it
>
> I have libm17n-0 1.6.2-3 installed. It should satisfy both the old
> and the new Recommends since both are ">=" relationships. Right? And
> it seems to do so okay. I can install either version of m17n-contrib
> without any dependency breakage.
You have to look very close. :)
You have installed libm17n-0 in version 1.6.2-3
The old version of m17n-contrib recommends >= 1.5.0
The new version of m17n-contrib recommends >= 1.6.3
As 1.50 < 1.6.2 < 1.6.3 is true, the recommends is NOT satisfied
any more in the new version as long as apt can't upgrade libm17n-0
to a version >= 1.6.3 together with the upgrade of m17n-contrib.
> In this case isn't 'upgrade' maintained? The list of names of the
> packages installed would be exactly the same both before and after.
> Only the version number of exactly one package is increased. Isn't
> that a safe upgrade?
As i don't know the reasoning behind m17n-contrib recommends
(yet alone i don't even know the package itself) lets use a simple
self-made example instead:
You have a good game and it can be played in single- and multiplayer.
The game only recommends the server-package needed for multiplay
as you could have a lot of fun even without ever being connected to
a network just by playing the singleplayer campaign.
As it can have strange effects if server and game version doesn't match
the server denies clients to join a game with a higher version then the
server has (as he just doesn't know how to handle them correctly).
The situation therefore:
Package: game
Version: 1
Recommends: server (>= 1)
Package: server
Version: 1
No let the maintainer upload a new version of game
Package: game
Version: 2
Recommends: server (>= 2)
If you install this new version now without waiting for a new version for
server, too, you loose the ability to join games on your own server.
That's a loose of functionality you don't want in 'upgrade'…
Or for a real example look at how linux-image-.* packages containing the
kernel recommends to install the firmware-linux-free package.
What does it help to 'upgrade' to a new kernel if the new kernel can't
cope with the old firmware files - parts of your hardware wouldn't be usable
anymore after this upgrade!
(Still not everyone on the planet has the same hardware, so you might
be lucky and survive without the firmware in the first place hence it
is "just" a recommends)
Best regards
David Kalnischkies
P.S.: Harshula, debian-ment...@lists.debian.org [0] and
http://mentors.debian.net/ might be helpful to find a sponsor.
Might be that Axel Beckert as the original reporter (and therefore
with a high interest on that) is interested in helping you out, too.
[0] http://lists.debian.org/debian-mentors/
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