Public SourceMage Discussion List

[Bor Kraljič <pyrobor AT ver.si>]

Is there any progress ? I think quite few of us tested libpng14 tested it and 
report problems and solve most of them. What needs to be tested before the 
merge into the test grimoire ? Any idea when the merge will happen ?

regards,
Bor

On Wednesday 11 of August 2010 16:57:36 Remko van der Vossen wrote:
> Hi everyone,
> 
> SHORT VERSION
> 
> Please test libpng 1.4:
>   - scribe add libpng from 
> git://download.sourcemage.org/smgl/grimoire.git:libpng:devel-libpng
>   - cast libpng
>   - report success and failure on the wiki page
> 
> For more info see: http://sourcemage.org/Grimoire/libpng14
> 
> LONG VERSION
> 
> libpng 1.4 has been out for a while now, but upgrading to 1.4 isn't as
> easy as any old version bump. The problem is that 1.4 is both API as
> well as ABI incompatible with 1.2. This means that we need to develop a
> seemless upgrade path where all spells that need a recast will be recast
> upon a libpng upgrade. Additionally we need to find and fix any spells
> that are incompatible with libpng 1.4.
> 
> The libpng spell was made multiversion for both 1.2 and 1.4 in master.
> This has been reverted in lieu of a devel-libpng git branch for several
> reasons, (disclaimer; this is just my opinion, feel free to disagree):
> 
>   1.  The spell didn't include any upgrade path, if a user simply did a
>       cast libpng all dependees of libpng (even indirect ones due to the
>       lovely libtool mess) would break because they can't link to
>       libpng12.so.0 which is suddenly gone. Users can't be expected to
>       run a cast -B -c for a simple spell upgrade. And of course even if
>       they were it wouldn't happen on a sorcery -s and then still our
>       dependency tree isn't as complete as it should be, so a cast -B
>       could easily miss spells that need to be recast.
> 
>   2.  libpng 1.4 should not go to stable grimoire as long as there are
>       spells that fail on it. Meaning that the libpng commit, as well as
>       all related fix commits of other spells would need to be reverted
>       each time a stable-rc is branched off as long as we aren't done
>       with libpng testing.
> 
>   3.  By making the libpng spell multiversion we need to support both
>       version 1.2 and 1.4. So instead of just making sure the other
>       spells work with 1.4 we need to also have it keep working with
>       1.2. By moving the libpng development to a git branch and simply
>       doing a straight upgrade instead of a multiversion we sidestep
>       this issue.
> 
>   4.  Test grimoire ins't a dumping ground for new developments, yes,
>       test can from time to time contain things that don't work,
>       especially compatibiluty problems between upgraded spells and
>       other spells, that is what test is for. But we shouldn't knowingly
>       put broken spells, or spells with known collateral damage into
>       test. This is such a case; this is an ABI and API incompatible
>       upgrade of a package which a lot of other packages depend on
>       directly or indirectly, we expect major breakage here. We need to
>       flesh out most of the problems we expect to see before we shoot it
>       out to a larger audience.
> 
> So, I made a devel-libpng branch, and in it updated the libpng spell to
> version 1.4.3 and included an UP_TRIGGERS script that checks all
> installed spells for ELF dynamic objects that link to libpng and
> triggers a cast self on those that do.
> 
> I tested it on my home box, and found a few spells incompatible with
> libpng 1.4 and fixed as much as I could. The current status can be found
> on the libpng 1.4 wiki project page:
> 
>   http://sourcemage.org/Grimoire/libpng14
> 
> Please help out and test the devel-libpng14 branch, let's prove we can
> work with branches effectively. All you need to do is install a grimoire
> based on the devel-libpng branch as described in the short version above
> and cast libpng. Naturally if you already have a git based repo you can
> also just switch it to the libpng branch.
> 
> Please report any success and failure on the wiki page. And if you can
> and have the time, please commit any libpng 1.4 related fixes to the
> devel-libpng branch. see http://sourcemage.org/Git_Guide for info on
> working with git branches.
> 
> Regards,
> 
> Remko van der Vossen
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