[SCM] Samba Shared Repository - branch master updated - release-4-0-0alpha8-154-g826ee30

[Jeremy Allison]

On Thu, Jul 02, 2009 at 08:14:11AM +1000, tridge at samba.org wrote:
> Hi Jeremy,
> 
>  > What about Metze's suggestion, wouldn't that keep the bugfix
>  > without breaking the ABI ?
> 
> It's a neat idea certainly, but I wonder how long we have to keep it
> in? 

For as long as we're shipping talloc.so.1.x. That's the promise
we made when we released talloc as an external library.

> It isn't completely without cost, as it creates a new trap for
> programmers. If someone forgets to #include <talloc.h> in some module
> in their application but they use these parts of the talloc API then
> they will not get a compile/link error, they'll get these ABI
> compatibility functions. In this case the two functions are very
> similar, so it would probably cause very few problems, but if we ever
> want to get rid of these ABI compat functions then we'll need to bump
> the soname number anyway.

Yes - that's the point. You got rid of them without
bumping talloc to talloc.so.2. Now you might want to do
this for this bugfix but it really doesn't warrent that
sort of a change (IMHO) and will lead to multiple versions
of the talloc ABI that I really don't think we should do.

> I don't want the tail wagging the dog in Samba. I don't want the fact
> that some of our code is used in shared libraries to constrain the way
> we develop Samba, and how we fix bugs. With .so numbering we don't
> need to be constrained and we can fix bugs in the best way we can
> find.

But we've released this library. We've gotten people using it
in other applications. This isn't only our code anymore.

We *have* to maintain backwards compatibility with small
bugfixes like this in order to maintain *any* credibility
as a provider of system libraries. It isn't like Metze's
fix is hard to do or would damage the code in any way. It
just shows a commitment to ABI stability.

If this were a larger change, which warrented talloc2,
then I'd agree. But to arbitrarily change the ABI like
this when we don't have to is gratuatous change, that
gives Free Software production a bad name.

Jeremy.