Add <package>_VERSION output variable to cmake_find_package generator (…

…#4257)

This standard find_package() output variable allows users to query
the found library version. Note this variable is defined for requested
packages only, not _VERSION variables are defined for the package
dependencies.

conans/client/generators/cmake_find_package.py

@@ -3,19 +3,25 @@
 
 
 generic_find_package_template = """
+include(FindPackageHandleStandardArgs)
+
 message(STATUS "Conan: Using autogenerated Find{name}.cmake")
 # Global approach
 SET({name}_FOUND 1)
+SET({name}_VERSION "{version}")
 SET({name}_INCLUDE_DIRS {deps.include_paths})
 SET({name}_INCLUDES {deps.include_paths})
 SET({name}_DEFINITIONS {deps.defines})
 SET({name}_LIBRARIES "") # Will be filled later
 SET({name}_LIBRARIES_TARGETS "") # Will be filled later, if CMake 3
 SET({name}_LIBS "") # Same as {name}_LIBRARIES
 
-mark_as_advanced({name}_FOUND {name}_INCLUDE_DIRS {name}_INCLUDES
-                 {name}_DEFINITIONS {name}_LIBRARIES {name}_LIBS)
+find_package_handle_standard_args({name}
+    REQUIRED_VARS {name}_VERSION
+    VERSION_VAR {name}_VERSION)
 
+mark_as_advanced({name}_FOUND {name}_INCLUDE_DIRS {name}_INCLUDES
+                 {name}_DEFINITIONS {name}_LIBRARIES {name}_LIBS {name}_VERSION)
 
 # Find the real .lib/.a and add them to {name}_LIBS and {name}_LIBRARY_LIST
 SET({name}_LIBRARY_LIST {deps.libs})
@@ -84,6 +90,7 @@ def _single_find_package(name, cpp_info):
         if cpp_info.public_deps:
             lines = CMakeFindPackageGenerator._transitive_lines(name, cpp_info)
         tmp = generic_find_package_template.format(name=name, deps=deps,
+                                                   version=cpp_info.version,
                                                    find_dependencies="\n".join(lines))
         return tmp
 

conans/test/functional/generators/cmake_find_package_test.py

@@ -44,6 +44,7 @@ def build(self):
 cmake_minimum_required(VERSION 3.1)
 find_package(Test)
 message("Libraries to Link: ${Test_LIBS}")
+message("Version: ${Test_VERSION}")
 
 get_target_property(tmp Test::Test INTERFACE_LINK_LIBRARIES)
 message("Target libs: ${tmp}")
@@ -55,6 +56,7 @@ def build(self):
         client.run("create . user/channel --build missing")
         self.assertIn("Library fake_lib not found in package, might be system one", client.out)
         self.assertIn("Libraries to Link: fake_lib", client.out)
+        self.assertIn("Version: 0.1", client.out)
         self.assertIn("Target libs: fake_lib;shared_link_flag", client.out)
         self.assertIn("Compile options: a_cxx_flag;a_flag", client.out)
 
@@ -125,6 +127,7 @@ def cmake_find_package_test(self):
 if(Hello0_LIBRARIES)
     MESSAGE("Hello0_LIBRARIES set")
 endif()
+message("Version: ${Hello0_VERSION}")
 add_executable(say_hello main.cpp)
 target_link_libraries(say_hello helloHello1)
 
@@ -133,6 +136,7 @@ def cmake_find_package_test(self):
         client.run("create . user/channel -s build_type=Release")
         self.assertIn("Conan: Using autogenerated FindHello0.cmake", client.out)
         self.assertIn("Hello0_LIBRARIES set", client.out)
+        self.assertIn("Version: 0.1", client.out)
         self.assertNotIn("Skipping already existing target", client.out)
 
         # Now link with old cmake
@@ -173,7 +177,7 @@ def cmake_find_package_test(self):
         self.assertIn("Conan: Using autogenerated FindHello0.cmake", client.out)
 
         # Now a transitive consumer, but the consumer only find_package the first level Hello1
-        files = cpp_hello_conan_files(name="Hello2", deps=["Hello1/0.1@user/channel"],
+        files = cpp_hello_conan_files(name="Hello2", version="0.2", deps=["Hello1/0.1@user/channel"],
                                       settings='"os", "compiler", "arch", "build_type"')
         files["CMakeLists.txt"] = """
 set(CMAKE_CXX_COMPILER_WORKS 1)
@@ -182,6 +186,7 @@ def cmake_find_package_test(self):
 cmake_minimum_required(VERSION 2.8)
 set(CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR} ${CMAKE_MODULE_PATH})
 find_package(Hello1 REQUIRED) # We don't need to find Hello0, it is transitive
+message("Version1: ${Hello1_VERSION}")
 
 add_library(helloHello2 hello.cpp)
 target_link_libraries(helloHello2 PUBLIC Hello1::Hello1)
@@ -196,3 +201,4 @@ def cmake_find_package_test(self):
         client.run("create . user/channel -s build_type=Release")
         self.assertIn("Conan: Using autogenerated FindHello0.cmake", client.out)
         self.assertIn("Conan: Using autogenerated FindHello1.cmake", client.out)
+        self.assertIn("Version1: 0.1", client.out)