Today I stumbled across this section in the policy and found it to be
confusing, self contradictory, contradictory
with the debconf man page and contradictory with common sense.
The proposals seem quite sensible if perhaps not in their final form,
but reading through the entire thread it seems to me that the thread
lost its way by looking at specific packages, for which presumably
someone can always come
up with reasons as to why the configuration files are particularly
sensitive. As such I will just explain ways in which I am confused by
the policy but I will try to avoid mentioning specifics.
Second paragraph: "The maintainer scripts must not alter a conffile of
/any/ package, including the one the scripts belong to."
This statement can be construed as prohibiting any automated generation
of configuration files, and any user interaction with the construction
of the configuration file via debconf.
Fourth paragraph: "If it is desirable for two or more related packages
to share a configuration file /and/ *for all of the related packages to
be able to modify that configuration file*, then the following should be
done:"
This statement contradicts the second paragraph.
As far as I can see if package A installs file pregenerated X where file
X was originally installed by package B and where A's control file has a
"Replaces: B" clause, then the system will know that file X is now owned
by package A.
However if package A modifies file X, for example by using "sed", the
system has no way of knowing that the file is
now owned by package A. I suspect that this might be what the policy
section is attempting to express, but it is not at all clear.
Sixth paragraph: "The owning package should also provide a program that
the other packages may use to modify the configuration file."
I suspect that a good example of this might be the "passwd" package
which provides utilities such as "useradd" to modify its configuration
files.
