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Re: First draft of review of policy must usage

On Wed, 25 Oct 2006 19:44:38 -0700, Steve Langasek <vorlon@debian.org> said: 

> On Wed, Oct 25, 2006 at 01:49:03PM -0500, Manoj Srivastava wrote:
>> > @@ -3195,8 +3112,8 @@
>> >          <p>
>> >            Additionally, packages interacting with users using
>> >            <tt>debconf</tt> in the <prgn>postinst</prgn> script
>> >            should
>> > - install a <prgn>config</prgn> script in the control area,
>> > - see <ref id="maintscriptprompt"> for details.
>> > + usually install a <prgn>config</prgn> script in the control
>> > + area, see <ref id="maintscriptprompt"> for details.
>> >          </p>
>> >  
>> >  	<p>

>> > You seem to have changed "should" to "should usually", and I
>> > don't see what the real difference is.

>> Not all packages have to install config files or be buggy -- for
>> example, packages that only ask questions based on information
>> available only after unpacking, for instance. Such packages may or
>> may not ask questions, and the question they ask may need values
>> gathered by programs that are contained in the package itself. In
>> this case, there can be no config file -- and all the questions are
>> conditionally asked in the postinst.

>> Since this is not the default, I use the term "should usually"
>> provide.  not an unconditional should provide.
> However, I think it's important that policy outline those cases in
> which it's not a bug to omit a .config script.

        I don't think I know _all_ use cases in which it is ok not to
 add a .config file. I can provide a few use cases. I think the reader
 should be allowed to make their own judgement calls, in case they
 have a use case we might miss.

> Doesn't the absence of the .config script require additional by-hand
> handling of the templates which is otherwise done automatically
> through apt?

        No. From debconf-devel (7):
|  A question is an instantiated template. By asking debconf to display  a
|  question,  your  config script can interact with the user. When debconf
|  loads a templates file (this happens  whenever  a  config  or  postinst
|  script is run), it automatically instantiates a question from each tem‐
|  plate. It is actually possible to instantiate several independent ques‐
|  tions  from the same template (using the REGISTER command), but that is
|  rarely necessary. 

>> >        <p>
>> > - Packages involving shared libraries should be split up into
>> > + Packages involving shared libraries ought to be split up into
>> >  	several binary packages. This section mostly deals with how
>> >  	this separation is to be accomplished; rules for files within
>> > - the shared library packages are in <ref id="libraries">
>> >  	instead.
>> > + the shared library packages are in <ref id="libraries">
>> > + instead.
>> >        </p>
>> >  
>> >        <sect id="sharedlibs-runtime">

>> > I think the "should" there was good.

>> This is something I want to discuss further. Consider the case
>> where there is a package with a set of, say, 20 binaries with a lot
>> of common code, and upstream decided to abstract it out into a
>> shared lib. This is a shred lib used by anyone else, and it is
>> changing rapidly enough that there is the equivalent of a soname
>> change on every upload. There is no interest in supporting older
>> versions, or even having multiple versions of that lib. In this
>> case, either we can make packaging that software hard (since moving
>> the lib out of /usr/lib etc may involve some work), or we allow
>> some packages to include share libs in the package.

> This tells me that the guidelines for when shared library packages
> must be split up are still ill-defined in some corner cases.  I
> don't think we should be gutting such an important requirement from
> policy just because there may be corner cases that need sorting,
> when the cost of non-compliance with this requirement is so high.

        Making a SHOULD directive a suggestion is hardly what I call
 gutting. However, since this is one area I was fuzzy about, and now I
 have seen two strong negative reactions, and none in favour, this
 seems like something that may be reverted.

"The Nazis have no sense of humor, so why should they want
television?" Philip K. Dick
Manoj Srivastava <srivasta@debian.org> <http://www.debian.org/~srivasta/>
1024D/BF24424C print 4966 F272 D093 B493 410B  924B 21BA DABB BF24 424C

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