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Re: apt-get upgrade conflicts



Adam Funk wrote:
> Thomas Adam wrote:
> > dist-upgrade should be used here.
> 
> In what circumstances is 'upgrade' more appropriate than 'dist-upgrade'?

The 'upgrade' keeps the list of packages installed on the system
exactly the same.  It does not allow changes.  Topologically the
package contour is identical.  If a package was installed previously
then it is still installed.  If a package was not installed previously
then it is not installed.  Only the versions numbers are allowed to
change.

The 'dist-uprade' additionally allows the list of packages installed
on the machine to change.  It allows it to either add more new
packages or to remove previously installed packages because of
conflicts.  The shape of things can change.

On a server where you are running 'stable' and are only allowing
security updates then 'upgrade' is most appropriate.  Debian policy
only allows security updates to fix the security issue and does not
allow them to change the shape of things.  They dependencies cannot
change.  They cannot pull in new packages, etc.  Therefore 'upgrade'
is best way to enforce that no functionality on a system is changing.

On a desktop running 'unstable' you have accepted that you are living
on the cutting edge.  Package topography changes can happen with every
package upload to unstable.  New packages appear.  Old ones are
replaced.  Dependencies change.  That does not mean broken but does
mean changing.  A 'dist-upgrade' is more like 'install' of every
already installed package on the system.  An 'upgrade' will force the
packages to remain the same and as soon as it sees that it needs to
pull in a new package it will hold the old ones because it can't pull
in a new package.  You must use 'dist-upgrade' to when riding the wild
bull.

The 'dist-upgrade' gets its name because you when changing from one
stable release to the next stable release you would use use
dist-upgrade to upgrade from one distribution to another.  From one
release to another many things change.  Living on unstable can be like
that every day.

Bob

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