[pacman-dev] [RFC] Find real library names with libdepends/libprovides

[Allan McRae]

On 09/05/13 14:52, Mohammad_Alsaleh wrote:
> I'm going to reply here before going into details about the individual
> patches if that's okay.
> 
> On Wed, May 08, 2013 at 07:59:53PM -0400, Dave Reisner wrote:
>> On Thu, May 09, 2013 at 12:15:27AM +0300, Mohammad Alsaleh wrote:
>>>
>>>   makepkg only handles libprovides/libdepends correctly if the naming
>>>   scheme is:
>>>
>>>     lib${name}.so --> lib$name.so.$ver
>>>
>>>   But it is not uncommon for libname.so to link to a '.so' file that
>>>   does not follow this naming scheme. For example, these 2 schemes are
>>>   sometimes used:
>>>     lib$name.so --> libname$major.$major.$minor
>>>     lib$name.so --> libname-$major.$major.$minor
>>>
>>>   There exists other schemes.
>>
>> Can you point out where these exist in the wild? They're hugely
>> non-conformant, and glibc's ldconfig won't even read these files without
>> specific nudging. I'm not sure how other implementations behave.
>>
> 
> Attaching a small script that should list all cases in '/usr/lib'.
> There are 72 library names detected by this script in my system.
> 
> Actually, I came across this when I wanted to suggest adding libprovides
> to popular libraries after libpng's upgrade. And when I tested adding
> 'libpng.so' to provides. I discovered that current code in makepkg
> wouldn't work.
> 
> Investigating this further, I discovered that libpng is not a corner
> case as shown by the output of the small script attached.
> 

Ah.  So libpng is interesting...   it has:
libpng.so -> libpng16.so -> libpng16.so.16.2.0

Putting libpng.so in provides does not work.  But putting libpng16.so
does.   And the actual library software links to is libpng16.so meaning
that should be in the depends line too.

I refuse to have makepkg actually change the specified dependency.  It
is only allowed to add a version to it.   So this is not a bug.

Allan