Re: config(5) break down

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Fri, 26 Mar 2010 14:52:09 +0900
    From:        Masao Uebayashi <uebayasi%gmail.com@localhost>
    Message-ID:  
<70f62c5e1003252252h6e5ba506xfafceb76f854b957%mail.gmail.com@localhost>

  | You need to include dependency.  You don't need to care the order of
  | include lines.  This is pretty much same as C headers including its
  | dependency vs. not include in *.h but managing the order in *.c.

But C include files are a disaster - a huge mess inherited from history.
No-one sane would deliberately design that as a solution for anything.
As a user of the things I'd much rather all that just happened automatically,
when I use fopen() if the compiler needs stdio.h, it should just go and
get stdio.h - it's absurd to make me explicitly say I need it.

For C, because of the nature of the world 30+ years ago, and development
since, there's nothing we can do about it.   But copying that as if it was
a great system would be absurd.

  | Same as pkgsrc "buildlink3.mk" including its dependency too.

No, those are totally different - those are different files because
they're managed separately, as a part of each package - the maintainer
of graphics/jpeg looks after jpeg/builink3.mk and makes it does whatever
is necessary to correctly link whatever -ljpeg required.  Those are
separate files, not because separate files is a good thing, but because
the management of anything different would be a nightmare.

If your reason for lots of little conf files was because there are lots of
little independent projects, each producing and looking after their own
little piece of the puzzle, that would be something that might reach
agreement (if it were correct).

But the reason seems to just be this dependency ordering thing - which it
looks like you're planning on solving it the .h file way (with each file
including anything it needs, then added protection against including anything
more than once, and ... which is all just a huge mess).

That's not the way to fix this problem.  If it has become serious enough that
doing it manually is no longer sensible, then just fix config to remove the
ordering rule - I don't think there's any good reason for it (and you certainly
are not proposing making it stronger).   Making config do a two pass parse of
the config file(s) would be an afternoon's work - it was never done that way
because manual ordering started out being so simple to do, that the afternoon's
work was never justified.   Then, as each new entry was added, manually 
ordering that new entry was always less than that afternoon's work.  Almost
certainly the sum of all of that effort is (now) greater than the effort it
would have taken to fix config, but no-one has ever really fallen against
it hard enough that they could justify spending the afternoon to fix it.

Maybe that's changed now - certainly I suspect that there's been more time
spent on this discussion than it would take to have just fixed config in the
first place.

  | Having a
  | single *.conf per module is natural.  As natural as userland commands
  | and libraries have a single Makefile for each.

This one is a different argument (and as I remember this is more where
you started, before you got onto that ordering nonsense), this relates more
to management, and is much more reasonable.

However, since I'm a believer in the single module kernel, that also makes
me a believer in the single files.conf file - and for people like me,
following this line of reasoning, you'd agree right?  (Regardless of whether
or not you agree with the single module approach).

  | >   I'm not saying changing syntax is bad.  My complaint is that David
  | >   Holland is suggesting things without understanding the existing
  | >   syntax.  I spent a whole weekend to read sys/conf/files, ioconf.c, and
  | >   module stubs in sys/dev/usb/uaudio.c.  I wasted a whole weekend.  I've
  | >   been wasting more time to convince David Holland who has never
  | >   bothered to understand the existing syntax.

I'm pretty sure he understands the existing syntax.  I am pretty sure that
I understand the existing syntax as well.   The syntax of what is in the
file(s) is pretty much an orthagonal issue - I certainly agree that the
syntax could be improved, but I don't see that having almost any bearing
upon the multiple files issue - it doesn't need to change to allow a 2 pass
parser to remove any ordering relationship on the config file lines,
and it can change, whether we have one config file (as it once was), a dozen
or whatever it is now, or a hundred or more (your proposal).

When mrg said he wanted to cry, or laugh, at your message, I suspect it
was because if there had been a zillion little files, the weekend you spent
would probably have been at least a week....

And lastly, it isn't just David you need to convince - that only one person
is arguing with you doesn't mean only one person believes what he is saying
(and that only you are arguing for your proposal doesn't mean that only
you believe that is the best way).   It was your comment that you could
just say "only dholland disagrees" that caused me to decide to comment
(just this once) - in general, when someone else is stating my position,
I just keep quiet, there's no real purpose to be served in "me too" messages.

kre