splitout of samba-debug (was: Re: [SCM] Samba Shared Repository - branch master updated)

[Simo]

On Thu, 2015-01-15 at 16:53 +0100, Jelmer Vernooij wrote:
> On Thu, Jan 15, 2015 at 10:47:32AM -0500, Simo wrote:
> > On Thu, 2015-01-15 at 15:27 +0100, Jelmer Vernooij wrote:
> > > On Thu, Jan 15, 2015 at 03:17:59PM +0100, Volker Lendecke wrote:
> > > > On Thu, Jan 15, 2015 at 12:54:53PM +0100, Jelmer Vernooij wrote:
> > > > > On Thu, Sep 18, 2014 at 11:03:03PM +0200, Volker Lendecke wrote:
> > > > > >        via  25df58a lib: Make samba-debug a private library
> > > > > 
> > > > > > commit 25df58a853d8d3ecab2705687453193cb676976c
> > > > > > Author: Volker Lendecke <vl at samba.org>
> > > > > > Date:   Thu Sep 18 14:50:50 2014 +0200
> > > > > > 
> > > > > >     lib: Make samba-debug a private library
> > > > > >     
> > > > > >     Signed-off-by: Volker Lendecke <vl at samba.org>
> > > > > >     Reviewed-by: Jeremy Allison <jra at samba.org>
> > > > > > 
> > > > > 
> > > > > This change removes the debug library symbols from our public libraries, making
> > > > > them inaccessible to any non-Samba code - including OpenChange. As Julien just
> > > > > discovered, this breaks the use of OpenChange with Samba 4.2.
> > > > > 
> > > > > Can we revert this change, at least for 4.2? We can discuss whether
> > > > > OpenChange should use the Samba DEBUG() interface or whether it can do its
> > > > > own logging, but that would not be an easy change to make this far in the cycle.
> > > > 
> > > > Feel free. I don't like it that we now can't change our
> > > > internal library structures anymore, but if we have to do
> > > > this, then feel free to revert my changes.
> > > I'll coordinate with Julien. The cleanup seems useful and I don't think we
> > > should hold back on it in general, it's just that this particular one is problematic
> > > for OpenChange.
> > 
> > Openchange can't simply define their own DEBUG() macro ?
> > It's not hard ...
> If it does, it won't be able to write to the Samba log files. It would also
> force OpenChange to use the exact same signature for its DEBUG() macro
> as Samba currently has, rather than something that suits it.

I am sure openchange can open the same log files if it really wants,
as a Samba developer though I would prefer *not* to have another program
logs mixed with samba's ... so that a feature not a problem to me.

> > > > How do we make sure we don't mess up things again? This kind
> > > > of cleanup will happen again, and we need a strict check for
> > > > this in autobuild.
> > > There is infrastructure in the build system to prevent API/ABI changes, which
> > > we already use for talloc/tevent/tdb/ldb. We should use it for the public Samba
> > > libraries too.
> > 
> > Except we haven't done this so far because our non-stable libraries are
> > in no condition to stabilize. We need to first decide what are public
> > and what are private interfaces, then split headers and filter private
> > symbols out of the public libraries (by moving them in private libs).
> It would allow us to at least detect when we make changes to the current
> public API/ABI. When we are aware of the changes we are making, we
> can decide whether those changes are acceptable.

I can't call the current API "public", to me that word have a
connotation of endorsement. We just throw out some stuff without
carefully looking at it.
So that's our fault for sure, but making this "public" API a real public
API requires some more than just an APIABI checker which we just wave
all the time.

> Considering the current set of public APIs to be set in stone seems
> unreasonable, but we should at least be careful when making changes
> to APIs in use by external projects like OpenChange or FreeIPA.

Indeed, we need to be careful, by stopping throwing random private
functions in the public headers.

Simo.

-- 
Simo Sorce