ccan dependencies seems to break external projects

[Matthieu Patou]

On 02/12/2012 04:52 AM, Jelmer Vernooij wrote:
> On Sat, Feb 11, 2012 at 02:49:20PM -0800, Matthieu Patou wrote:
>> I'm trying to compile openchange as described here : http://tracker.openchange.org/projects/openchange/wiki/HowTo_Install_OpenChange_From_Source
>>
>> I'm using the latest git tree instead of alpha17, after a couple of
>> tweak in the script that setup the prerequisits I have a samba4 with
>> using system talloc/tdb/tevent and ldb.
>>
>> Then I try to build openchange and got:
>>
>>
>> /usr/local/src/openchange$ make
>> Linking sample application bin/libmapixx-test
>> g++ -I.  -O3 -Wall -g3 -fstrict-aliasing -Wp,-D_FORTIFY_SOURCE=2
>> -DHAVE_IMMEDIATE_STRUCTURES=1 -D_GNU_SOURCE=1
>> -Wl,-rpath,/usr/local/samba/lib -I/usr/local/samba/include
>>     -I/usr/local/samba/include   -I/usr/local/samba/include
>> -I/usr/local/samba/include     -o bin/libmapixx-test
>> libmapi++/tests/test.cpp libmapipp.so.0.11 libmapi.so.0
>> .11 -Wl,-rpath,/usr/local/samba/lib -L/usr/local/samba/lib -ldcerpc
>> -ldcerpc-binding -lndr -lsamba-hostconfig -lsamba-util -ltevent
>> -ltalloc   -Wl,-rpath,/usr/local/samb
>> a/lib -L/usr/local/samba/lib -lldb -ltalloc
>> -Wl,-rpath,/usr/local/samba/lib -L/usr/local/samba/lib -ltalloc
>> -lpthread
>> /usr/local/samba/lib/libsmbconf.so.0: undefined reference to
>> `hash_any at SAMBA_4.0.0ALPHA18_GIT_0B3A262'
>>
>>
>> The hash_any symbol comes from the ccan library and is included in
>> libsmbconf.so via source3/util/
>>
>> I suspect there is a symbols collision when you build samba 4 with
>> system libs as ldb has its own version of ccan but obviously with a
>> different version although it seems that ldb didn't directly need
>> ccan (no ccan in the output of ldd libldb.so), the following command
>> ls /usr/local/systemsamba/lib/ldb/libccan.so.0* output this:
>>
>> /usr/local/systemsamba/lib/ldb/libccan.so.0
>> /usr/local/systemsamba/lib/ldb/libccan.so.0.1-init-1161-g661d41f
>>
>> There is no way to have a system ccan and it seems that there is no
>> easy way to use the one built for ldb as the "system" ccan.
>>
>> I don't know what can be done, the cheapest is to have a
>> source3/util not to depend on ccan if --disable-tdb2 was specified
>> on the command line.
> Does ccan really have to be a separate library? Its goal seems to be
> the same as the 'samba-util' library.
>
> If I understand correctly ccan isn't really meant as a shared library
> with utility functions but rather as a collection of C files that you
> can pick a few useful ones from.
>
> Would it perhaps be possible to just include the relevant files from
> ccan in libsamba-util?
I'm not sure how this will fix the problem.
Let say that we have ccan in samba-util, instead of depending on ccan, 
ldb will depend on samba-util.
It means if I understand well that we will have a libsambautil.so with a 
version 1.4.1 (the version of ldb) but as it seems that we have no way 
to use a system samba-util library when building samba4 will have also a 
version of this library SAMBA_4.0.0ALPHA...

I might have got something wrong.

Matthieu.

-- 
Matthieu Patou
Samba Team
http://samba.org