cmake and linking issues

[Stephen Kelly]

Giorgos Tsiapaliokas wrote:

> find_package(KDE4Support REQUIRED NO_MODULE)
> find_package(KDELibs4 REQUIRED NO_MODULE)
> 
> So should the find_package be written like this?
> Is it normal to fail otherwise?

There are likely two issues:

1) a bug in cmake fixed in master with 
 
 http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=0ad2a1c181

2) The targets in those libraries link publically to other targets, but the 
dependency is not found in the Config file.

This relates to what I've pointed out a million times. If a dependency is 
only used internally, use the PRIVATE keyword to target_link_libraries. If 
users of the framework must also link to the dependency, make it PUBLIC and 
also add find_dependency() for the dependency to the config file.

For example, if I write:

 find_package(KIO REQUIRED)

I get this:

CMake Error at CMakeLists.txt:6 (find_package):
  Found package configuration file:

    /home/stephen/dev/prefix/qtbase/kde/lib/x86_64-linux-
gnu/cmake/KIO/KIOConfig.cmake

  but it set KIO_FOUND to FALSE so package "KIO" is considered to be NOT
  FOUND.  Reason given by package:

  The following imported targets are referenced, but are missing:
  KF5::KBookmarks KF5::XmlGui KF5::Solid


For example, either KIO should link privately to solid instead of 
publically, or there should be a find_dependency(Solid) in the KIO config 
file. Which is it?

There should be an effort to get this right, because it matters for 
compatibility guarantees.

Thanks,

Steve.