tdb_chainlock() in tdb1, tdb2 and tdb_compat ?

[Volker Lendecke]

On Thu, Apr 12, 2012 at 01:55:59PM -0700, Jeremy Allison wrote:
> On Thu, Apr 12, 2012 at 04:58:30PM +0200, Volker Lendecke wrote:
> > So hypothetical callers checking
> > 
> > if (tdb_chainlock(...) == -1) {
> > 	/* error path */
> > }
> > 
> > silently would become wrong.
> 
> Ouch. This is a *BIG* API problem (IMHO). Any tdb_compat()
> layer has to provide *exact* tdb1 semantics or we're setting
> ourselves up for a world of pain with different semantics
> called from code that doesn't expect it.

One problem here is that the tdb_compat layer if I
understand it correctly (which is far from certain) was
designed to make samba on tdb2 just barely compile. For
example it has a tdb_fetch replacement which for the better
has a completely different prototype which the compiler
would not accept. However, we end up with a tdb_fetch symbol
in libraries, static objects or somewhere else with two
completely different meanings. This alone will lead to all
sorts of problems, at least it will require a lot of care
and coordination not to cause hickups.

Volker

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