Bug#479950: java-gcj: java alternative overwritten

[Matthias Klose <doko@cs.tu-berlin.de>]

> On Wed, May 07, 2008 at 12:04:44PM +0200, Matthias Klose wrote:
> > maybe this works for the simple case, but how is it technically
> > possible to keep an alternative in manual state, if you change
> > priority, add or remove slave links?
> 
> Neither of these actions cause the manual status to change since they're
> simply calling "update-alternatives --install" in ways that don't affect
> what the alternative points to.
> 
> The manual state of an alternative refers to the state where the
> alternative has been changed to point to something other than the "best"
> alternative and has not been set back to auto since.  The problem here
> is that the package's prerm is *always* removing the alternative
> instead.  This forces the alternatives database to set the alternative
> back to auto since the configured alternative no longer exists.
> 
> The proper approach is to only remove the alternative in prerm if $1 is
> "remove" or "deconfigure".

which exactly doesn't work when changes are made.