cvs commit: src/sys/sys mbuf.h src/sys/kern uipc_mbuf.c uipc_syscalls.c src/usr.bin/netstat mbuf.c src/lib/libc/sys sendfile.2

[Ken Smith]

On Fri, Jun 18, 2004 at 03:48:13AM +0700, Max Khon wrote:
> Hi, Ken!

Hi, Max!  ;-)

I hope none of this is taken personally.  I have some relatively new
responsibilities being on re@ and I'm using this as a way to make sure
I really do understand how things are supposed to work.  I think I have
a reasonably good handle on it but it never hurts to test it to make
sure.  :-)

> On Thu, Jun 17, 2004 at 02:45:18PM -0400, Ken Smith wrote:
> 
> > > > This will break scripts.
> > > > 
> > > > Please back out the netstat change.
> > > 
> > > No problems, but can you tell me which scripts or programs
> > > has become broken after this change?
> > 
> > The scripts that are now potentially broken don't necessarily need to
> > be in the base system.
> 
> I did not say that I am interested in base system scripts only :)

Ok, sorry about that.

> > They could very well be scripts Alfred wrote
> > and uses himself for his own purposes.  Once a branch goes into -STABLE
> > status we try to not make 'user-visible' changes to it unless they are
> > bugfixes or do not alter the way something had worked.
> 
> As Bosko noted the change _adds_ a few lines to netstat -m output.
> Old output is not altered.
> Frankly speaking I can't imagine a script that could correctly parse
> netstat -m output before, but now is broken.

I may work with student programmers too much, but I'm afraid my imagination
is a bit better than yours in this case.  :-(

I don't defend it as being the right way to do things, but in cases where
the user is interested in "most of" the output of something they will often
take the approach of removing things they don't want instead of selecting
things they do want.  This change would add an extra line to what the
next stage of processing would see if that approach is used.

This particular change is a case of nit-picking.  It's small, hard to
imagine how it could effect someone, etc.  But even Bosko said more
caution 'next time' would be good, I'm just emphasizing why.  To some
extent the output of programs has been an API ever since pipes were
invented.  And unless I'm severely mistaken one of the things we have
tried to avoid is changing API's once a branch goes -STABLE.

-- 
						Ken Smith
- From there to here, from here to      |       kensmith at cse.buffalo.edu
  there, funny things are everywhere.   |
                      - Theodore Geisel |