cmake unable to report INCLUDE_DIRS and LIBRARIES

[Halton Huo]

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.1 LTS
Release: 16.04
Codename: xenial

$ dpkg -l|grep libjsoncpp
ii libjsoncpp-dev:amd64 1.7.2-1 amd64 library for reading and writing JSON for C++ (devel files)
ii libjsoncpp1:amd64 1.7.2-1 amd64 library for reading and writing JSON for C++

When try to use jsoncpp, the ${jsoncpp_INCLUDE_DIRS} and ${jsoncpp_LIBRARIES} fail to report.

CMakeLists.txt
----------------
cmake_minimum_required(VERSION 2.6.2)
project(jsoncpp_test)

find_package(jsoncpp REQUIRED)
message("FOUND CONFIG: ${jsoncpp_CONFIG}")
message("INCLUDE DIRS: ${jsoncpp_INCLUDE_DIRS}")
message("LIBRARIES: ${jsoncpp_LIBRARIES}")

The actual result is:
--------------------
FOUND CONFIG: /usr/lib/x86_64-linux-gnu/cmake/jsoncpp/jsoncppConfig.cmake
INCLUDE DIRS:
LIBRARIES:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Gianfranco Costamagna (costamagnagianfranco)]

Hello, as workaround, using pkg-config to detect it should work
pkg_search_module(JSONCPP jsoncpp)

[Timo Röhling (roehling)]

The CMake config exports the `jsoncpp_lib` and `jsoncpp_static` targets, which will automatically perform all required settings when used with `target_link_libraries()`. Manually setting the include paths and link libraries is an anti-pattern.