[augeas-devel] Re: New example at creating a lens

[David Lutterkort]

On Wed, 2009-07-15 at 16:21 +0200, Free Ekanayaka wrote:
> The point is probably that even if the lens gets merged upstream, that
> doesn't make much difference. 

It's at least the right answer to the question of lens versioning - that
way you can be sure that you always have the lens that matches the
version of your daemon. And as Raphael said, maintaining the lens
together with the distro package is a good first step to pushing the
lens upstream.

> If we allow other packages to modify the
> configuration file provided by some package, that package has to
> ensure that upgrades happen smoothly and that the semantics of the
> modification is preserved.

There's actually two separate issues: (1) package A needs to modify a
config file that belongs to package B (e.g., add an entry
to /etc/services) Whether that is appropriate depends on what exactly
the file modification is. The expectation is that package B provides
appropriate lenses for its config files. (2) package X makes
backward-incompatible changes to its config file in an update. Augeas
can help with moving old config files forward assuming there are lenses
for both the old and the new format.

David