Re: how to compare versions
On Thursday 04 February 2010 10:49:28 Goswin von Brederlow wrote:
> Hideki Yamane <henrich@debian.or.jp> writes:
> > And I have a question - why should we avoid using pre-depends?
> > What kind of problem would it cause?
> > (it doesn't mean I want to use pre-depends, just curious)
>
> It adds additional strong restrictions on the order in which packages
> must be upgraded. Too many such restrictions and there might not be a
> way to upgrade at all. Somewhere before that you (via apt/aptitutde/...)
> get the effect that you have to temporarily remove packages to upgrade.
>
> The less restrictions there are on the order the easier it is to
> upgrade.
This is true in general, although it's perhaps worth noting that a rare pre-
depends on a priority required package like debconf by a priority optional or
extra package isn't likely to cause any trouble.
For reference, the policy manual has this to say:
"""
Pre-Depends should be used sparingly, preferably only by packages whose
premature upgrade or installation would hamper the ability of the system to
continue with any upgrade that might be in progress.
Pre-Depends are also required if the preinst script depends on the named
package. It is best to avoid this situation if possible.
"""
So, it's certainly better to avoid a pre-depends if possible, but if it's the
best technical solution, there is no reason not to use it.
Reply to: