the sorry saga of the talloc soname 'fix'

[tridge at samba.org]

Hi Jeremy and Simo,

 > Thanks a *lot* for this one Simo, much appreciated.

I'm finding all this congratulation rather disturbing. The patch from
Simo now creates the very problem you are all so keen to avoid.

With the soname bump we had lots of standard mechanisms in place (both
packaging and loader) to try to stop having two versions of the
library in place at the same time. It would be detected at package
install time, and also at runtime by Metze's patch.

Now let's look at what happens with this much applauded patch from
Simo.

 1) the major so versions of the libraries are now the same, so you're
 telling the packaging managers and the loader that they are
 compatible. So distros and users will quite happily mix the versions
 now.

 2) the code is not in fact now compatible, as the patch from Metze is
 still in there, so if anyone actually tries to load both of them,
 then it will abort(), with no feedback to the user on what is
 actually wrong, and no mechanism for them to fix it except to
 manually recompile one or both of the offending packages, if they can
 even work out what packages need changing.

As for avoiding this with symbol versioning, that's all well and good
on platforms that have symbol versioning, but many of the platforms
that we claim we support don't have that, so now we've left them out
in the cold.

The so major number change is a crude instrument for handling changes
in versions of libraries, but it is portable to all shared library
systems I know of, and it works. I really don't understand why there
is this revulsion at using the library version number for exactly what
it was designed for.

Cheers, Tridge