Bug#581818: luatex: zlib version check too strict

[Török Edwin <edwintorok@gmail.com>]

On 05/16/2010 08:08 PM, Hilmar Preuße wrote:
> On 16.05.10 Török Edwin (edwintorok@gmail.com) wrote:
> 
> Hi,
> 
>> If I install zlib1g 1.2.5 from experimental I get this error when running
>> luatex:
>> PANIC: unprotected error in call to Lua API (zlib library version
>> does not match - header: 1.2.3.4, library: 1.2.5)
>>
>> I think the version check is too strict, it would suffice to check
>> for 1.2.x. Why would luatex need to be rebuilt everytime zlib
>> version is changed?
>>
> In earlier times the version check was untightened. Instead of
> checking all chars of the zlib version, only 5 are checked:
> 
>     /* make sure header and library version are consistent */
>     const char* version = zlibVersion();
>     if (strncmp(version, ZLIB_VERSION, 5))
> 
> We could re-introduce the patch.

In this case you'd need to check 4 chars only, not 5.

> Can you confirm that a version
> change from 1.2.3.4 to 1.2.5 is harmless? 

The only thing that breaks is libxml2, which made some assumptions and
accessed some zlib internal data structures (that were never exported in
zlib.h), see here:
http://www.mail-archive.com/xml@gnome.org/msg07276.html

Other than that I've been running with zlib 1.2.5 installed in
/usr/local for quite a while (ever since it was released) and I haven't
encountered any issues.
(I usually rm-ed zlib 1.2.4/1.2.5 before upgrading any TeX related
packages, and restored it after, so luatex doesn't complain).

> I can provide a test
> binary for i386 if needed, sorry not amd64 with Debian unstable
> around.

Thanks, I have a 32-bit unstable chroot, I can test it there.

Best regards,
--Edwin