overriding CMAKE_MODULE_PATH

[Michael Jansen]

Am 15.08.2010 20:28, schrieb Alexander Neundorf:
> On Sunday 15 August 2010, Yury G. Kudryashov wrote:
>> Hi!
>>
>> Many (all?) KDE modules have the following string in the beginning of
>> CMakeLists.txt:
>>
>> set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules)
>>
>> What do you think about replacing this string with the following?
>>
>> set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules
>> ${CMAKE_MODULE_PATH})
>>
>> This would allow user to say, e.g.,
>>
>> cmake ${kdenetowrk_src_dir} -
>> DCMAKE_MODULE_PATH=${libktorrent_prefix}/share/apps/cmake/modules
> 
> Why would you want to do that ?

Because it is the right thing to do. The first line overriding it is
just plain wrong imho.

1. CMAKE_MODULE_PATH is documented in cmake at the same level as
CMAKE_PREFIX_PATH as a variable that changes behaviour. Which means a
user can and will expect he is able to override it. Which will break
with the first line.

2. KDE installs a ton of useful not kde related FindXYZ*.cmake files
into a path != /usr/share/cmake... . If a non kde project wants to use
it (even a small homegrown project) the user has to set
CMAKE_MODULE_PATH from the outside. Therefore he needs the line from
Yury in his CMakeLists.txt. Since we as kde are the poster child for
cmake usage we should implement our cmake files as examples for other to
copy.

3. If someone develops a small lib he plans to add as a kde dependency
he probably installs it into some non distro prefix so he doesn't need
root rights to install it. So he needs to override CMAKE_MODULE_PATH in
say koffice to make it pick up that location. And i would expect it to
work. Remember that his KDELIBS_PREFIX could be distro provided and
koffice is installed into /usr/local/ .

Mike