Re: symlinks replaced by directories and vice versa

[Goswin von Brederlow <brederlo@informatik.uni-tuebingen.de>]

Mario 'BitKoenig' Holbe <Mario.Holbe@TU-Ilmenau.DE> writes:

> Hello,
>
> IMHO, one of the most frequently re-appearing issues in package-upgrades
> is symlinks in previous package versions replaced by directories in
> current versions and vice versa.
> Although the Debian policy clearly states in 6.6 (4) "A directory will
> never be replaced by a symbolic link to a directory or vice versa" it
> seems to me that many package maintainers cannot deal well with this
> behaviour or just don't know it.

Afaik dpkg does not remember what is a link to and what is a directory
in a package so it can't properly track that change in the package and
can't differentiate it from the admin moving and linking a
directory. That is the bad news.

Now the good news. I think moving and linking directories could be
forbidden and be replaced by moving and mount --bind. It avoids the
pritfalls of symlinked dirs completly and provides all the features.

...
> However, since this is such a frequent source of bugs and since so many
> package maintainers seem not to be able to deal well with it, I'm asking
> myself, if it wouldn't make sense to change this behaviour to something
> which is more native to maintainers - i.e. automagically replace
> symlinks by directories and vice versa (which would natively equal a
> package upgrade to a package removal followed by an installation of the
> new version) or abort package installation if it occurs or something
> like this.

I think post etch this could be a good idea. But someone has to dig
into dpkg to implement it.

MfG
        Goswin