Re: HEADSUP: zlib updated [svn commit: r205471 - in head: . lib/libz lib/libz/contrib lib/libz/doc sys/sys]

On 3/26/10, Robert Watson <rwatson_at_freebsd.org> wrote:
> On Mon, 22 Mar 2010, Xin LI wrote:
>
>> A MFC of this update is planned, but we will have to make some rather
>> aggressive changes against the library and more testing.
>>
>> Please make sure that you have at least libxml2-2.7.6_2 in your ports tree
>>
>> before even thinking about updating your ports tree.  Older libxml2 uses
>> some knowledge of zlib internals that has been changed in this update
>> which
>> is known to cause problem.
>
> While the update sounds like a good idea (as does moving to symbol
> verisoning
> for this library), I'm not yet convinced an MFC is a good idea given the
> compatibility issues you describe.  Perhaps you could clarify a bit the
> failure mode: this affects only people who rebuild their ports using exactly
> the same ports versions, but after having done an upgrade that includes this
> update?  It sounds like existing binaries will continue to work since they
> will reference the old library version?

Yes, but the number of libraries which need to be fixed is a pain. If
you go the conservative (not ultra conservative) route, you'll have to
rebuild all dependencies of graphics/png and graphics/tiff (which
includes a ton of gnome apps, X, etc). Oh, and did I forget to mention
that libtool hardcodes paths and versioning information? Of course
most people won't see this fact until they run make delete-old-libs,
but it's a doosy... This is the primary reason why Gentoo Linux has a
script to clean up these [libtool] messes...

That point alone is a reason for being ultra-conservative with this
MFCing change. This won't affect folks building from scratch after
this commit, but it'll easily kill off an afternoon or day for folks
upgrading if they one isn't careful because the impact is large.

Of course scripting the activity to avoid these times of base system
library bumps is trivial, but my script that I whipped up still has
rough edges and I'd rather not submit it quite yet...

Thanks,
-Garrett